SOLR-11670: Implement a periodic house-keeping task.

solr/CHANGES.txt

@@ -186,6 +186,9 @@ New Features
 
 * SOLR-11960: Add collection level properties similar to cluster properties (Peter Rusko, Tomás Fernández Löbbe)
 
+* SOLR-11670: Implement a periodic house-keeping task. This uses a scheduled autoscaling trigger and
+  currently performs cleanup of old inactive shards. (ab, shalin)
+
 Bug Fixes
 ----------------------
 

solr/core/src/java/org/apache/solr/cloud/autoscaling/AutoScaling.java

@@ -166,9 +166,11 @@ public class AutoScaling {
 
   }
 
+  public static final String AUTO_ADD_REPLICAS_TRIGGER_NAME = ".auto_add_replicas";
+
   public static final String AUTO_ADD_REPLICAS_TRIGGER_DSL =
       "    {" +
-      "        'name' : '.auto_add_replicas'," +
+      "        'name' : '" + AUTO_ADD_REPLICAS_TRIGGER_NAME + "'," +
       "        'event' : 'nodeLost'," +
       "        'waitFor' : -1," +
       "        'enabled' : true," +
@@ -185,4 +187,27 @@ public class AutoScaling {
       "    }";
 
   public static final Map<String, Object> AUTO_ADD_REPLICAS_TRIGGER_PROPS = (Map) Utils.fromJSONString(AUTO_ADD_REPLICAS_TRIGGER_DSL);
+
+  public static final String SCHEDULED_MAINTENANCE_TRIGGER_NAME = ".scheduled_maintenance";
+
+  public static final String SCHEDULED_MAINTENANCE_TRIGGER_DSL =
+          "    {" +
+          "        'name' : '" + SCHEDULED_MAINTENANCE_TRIGGER_NAME + "'," +
+          "        'event' : 'scheduled'," +
+          "        'startTime' : 'NOW'," +
+          "        'every' : '+1DAY'," +
+          "        'enabled' : true," +
+          "        'actions' : [" +
+          "            {" +
+          "                'name':'inactive_shard_plan'," +
+          "                'class':'solr.InactiveShardPlanAction'" +
+          "            }," +
+          "            {" +
+          "                'name':'execute_plan'," +
+          "                'class':'solr.ExecutePlanAction'" +
+          "            }" +
+          "        ]" +
+          "    }";
+
+  public static final Map<String, Object> SCHEDULED_MAINTENANCE_TRIGGER_PROPS = (Map) Utils.fromJSONString(SCHEDULED_MAINTENANCE_TRIGGER_DSL);
 }

solr/core/src/java/org/apache/solr/cloud/autoscaling/ExecutePlanAction.java

@@ -45,7 +45,7 @@ import org.slf4j.LoggerFactory;
 
 /**
  * This class is responsible for executing cluster operations read from the {@link ActionContext}'s properties
- * with the key name "operations"
+ * with the key name "operations".
  */
 public class ExecutePlanAction extends TriggerActionBase {
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

solr/core/src/java/org/apache/solr/cloud/autoscaling/InactiveShardPlanAction.java

@@ -0,0 +1,102 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.solr.cloud.autoscaling;
+
+import java.lang.invoke.MethodHandles;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.solr.client.solrj.SolrRequest;
+import org.apache.solr.client.solrj.cloud.autoscaling.SolrCloudManager;
+import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.common.cloud.ClusterState;
+import org.apache.solr.common.cloud.Slice;
+import org.apache.solr.common.cloud.ZkStateReader;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class checks whether there are shards that have been inactive for a long
+ * time (which usually means they are left-overs from shard splitting) and requests their removal
+ * after their cleanup TTL period elapsed.
+ * <p>Shard delete requests are put into the {@link ActionContext}'s properties
+ * with the key name "operations". The value is a List of SolrRequest objects.</p>
+ */
+public class InactiveShardPlanAction extends TriggerActionBase {
+  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  public static final String TTL_PROP = "ttl";
+
+  public static final int DEFAULT_TTL_SECONDS = 3600 * 24 * 2;
+
+  private int cleanupTTL;
+
+  @Override
+  public void init(Map<String, String> args) {
+    super.init(args);
+    String cleanupStr = args.getOrDefault(TTL_PROP, String.valueOf(DEFAULT_TTL_SECONDS));
+    try {
+      cleanupTTL = Integer.parseInt(cleanupStr);
+    } catch (Exception e) {
+      log.warn("Invalid " + TTL_PROP + " value: '" + cleanupStr + "', using default " + DEFAULT_TTL_SECONDS);
+      cleanupTTL = DEFAULT_TTL_SECONDS;
+    }
+    if (cleanupTTL < 0) {
+      log.warn("Invalid " + TTL_PROP + " value: '" + cleanupStr + "', using default " + DEFAULT_TTL_SECONDS);
+      cleanupTTL = DEFAULT_TTL_SECONDS;
+    }
+  }
+
+  @Override
+  public void process(TriggerEvent event, ActionContext context) throws Exception {
+    SolrCloudManager cloudManager = context.getCloudManager();
+    ClusterState state = cloudManager.getClusterStateProvider().getClusterState();
+    Map<String, List<String>> cleanup = new LinkedHashMap<>();
+    Map<String, List<String>> inactive = new LinkedHashMap<>();
+    state.forEachCollection(coll ->
+      coll.getSlices().forEach(s -> {
+        if (Slice.State.INACTIVE.equals(s.getState())) {
+          inactive.computeIfAbsent(coll.getName(), c -> new ArrayList<>()).add(s.getName());
+          String tstampStr = s.getStr(ZkStateReader.STATE_TIMESTAMP_PROP);
+          if (tstampStr == null || tstampStr.isEmpty()) {
+            return;
+          }
+          long timestamp = Long.parseLong(tstampStr);
+          // this timestamp uses epoch time
+          long currentTime = cloudManager.getTimeSource().getEpochTime();
+          long delta = TimeUnit.NANOSECONDS.toSeconds(currentTime - timestamp);
+          log.debug("{}/{}: tstamp={}, time={}, delta={}", coll.getName(), s.getName(), timestamp, currentTime, delta);
+          if (delta > cleanupTTL) {
+            log.debug("-- delete inactive {} / {}", coll.getName(), s.getName());
+            List<SolrRequest> operations = (List<SolrRequest>)context.getProperties().computeIfAbsent("operations", k -> new ArrayList<>());
+            operations.add(CollectionAdminRequest.deleteShard(coll.getName(), s.getName()));
+            cleanup.computeIfAbsent(coll.getName(), c -> new ArrayList<>()).add(s.getName());
+          }
+        }
+      })
+    );
+    if (!cleanup.isEmpty()) {
+      Map<String, Object> results = new LinkedHashMap<>();
+      results.put("inactive", inactive);
+      results.put("cleanup", cleanup);
+      context.getProperties().put(getName(), results);
+    }
+  }
+}

solr/core/src/java/org/apache/solr/cloud/autoscaling/OverseerTriggerThread.java

@@ -121,13 +121,15 @@ public class OverseerTriggerThread implements Runnable, SolrCloseable {
     int lastZnodeVersion = znodeVersion;
 
     // we automatically add a trigger for auto add replicas if it does not exists already
+    // we also automatically add a scheduled maintenance trigger
     while (!isClosed)  {
       try {
         AutoScalingConfig autoScalingConfig = cloudManager.getDistribStateManager().getAutoScalingConfig();
-        AutoScalingConfig withAutoAddReplicasTrigger = withAutoAddReplicasTrigger(autoScalingConfig);
+        AutoScalingConfig updatedConfig = withAutoAddReplicasTrigger(autoScalingConfig);
-        if (withAutoAddReplicasTrigger.equals(autoScalingConfig)) break;
+        updatedConfig = withScheduledMaintenanceTrigger(updatedConfig);
-        log.debug("Adding .autoAddReplicas trigger");
+        if (updatedConfig.equals(autoScalingConfig)) break;
-        cloudManager.getDistribStateManager().setData(SOLR_AUTOSCALING_CONF_PATH, Utils.toJSON(withAutoAddReplicasTrigger), withAutoAddReplicasTrigger.getZkVersion());
+        log.debug("Adding .auto_add_replicas and .scheduled_maintenance triggers");
+        cloudManager.getDistribStateManager().setData(SOLR_AUTOSCALING_CONF_PATH, Utils.toJSON(updatedConfig), updatedConfig.getZkVersion());
         break;
       } catch (BadVersionException bve) {
         // somebody else has changed the configuration so we must retry
@@ -338,6 +340,15 @@ public class OverseerTriggerThread implements Runnable, SolrCloseable {
 
   private AutoScalingConfig withAutoAddReplicasTrigger(AutoScalingConfig autoScalingConfig) {
     Map<String, Object> triggerProps = AutoScaling.AUTO_ADD_REPLICAS_TRIGGER_PROPS;
+    return withDefaultTrigger(triggerProps, autoScalingConfig);
+  }
+
+  private AutoScalingConfig withScheduledMaintenanceTrigger(AutoScalingConfig autoScalingConfig) {
+    Map<String, Object> triggerProps = AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_PROPS;
+    return withDefaultTrigger(triggerProps, autoScalingConfig);
+  }
+
+  private AutoScalingConfig withDefaultTrigger(Map<String, Object> triggerProps, AutoScalingConfig autoScalingConfig) {
     String triggerName = (String) triggerProps.get("name");
     Map<String, AutoScalingConfig.TriggerConfig> configs = autoScalingConfig.getTriggerConfigs();
     for (AutoScalingConfig.TriggerConfig cfg : configs.values()) {

solr/core/src/java/org/apache/solr/cloud/autoscaling/ScheduledTrigger.java

@@ -28,10 +28,12 @@ import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.TimeZone;
+import java.util.concurrent.TimeUnit;
 
 import org.apache.solr.client.solrj.cloud.autoscaling.SolrCloudManager;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventType;
 import org.apache.solr.common.SolrException;
+import org.apache.solr.common.util.TimeSource;
 import org.apache.solr.core.SolrResourceLoader;
 import org.apache.solr.util.DateMathParser;
 import org.apache.solr.util.TimeZoneUtils;
@@ -143,6 +145,7 @@ public class ScheduledTrigger extends TriggerBase {
       }
     }
 
+    TimeSource timeSource = cloudManager.getTimeSource();
     DateMathParser dateMathParser = new DateMathParser(timeZone);
     dateMathParser.setNow(new Date(lastRunAt.toEpochMilli()));
     Instant nextRunTime, nextPlusGrace;
@@ -156,7 +159,8 @@ public class ScheduledTrigger extends TriggerBase {
           "Unable to calculate next run time. lastRan: " + lastRunAt.toString() + " and date math string: " + everyStr, e);
     }
 
-    Instant now = Instant.now(); // todo how to play well with simulation framework?
+    Instant now = Instant.ofEpochMilli(
+        TimeUnit.NANOSECONDS.toMillis(timeSource.getEpochTime()));
     AutoScaling.TriggerEventProcessor processor = processorRef.get();
 
     if (now.isBefore(nextRunTime)) {
@@ -182,7 +186,7 @@ public class ScheduledTrigger extends TriggerBase {
         log.debug("ScheduledTrigger {} firing registered processor for scheduled time {}, now={}", name,
             nextRunTime, now);
       }
-      if (processor.process(new ScheduledEvent(getEventType(), getName(), nextRunTime.toEpochMilli(),
+      if (processor.process(new ScheduledEvent(getEventType(), getName(), timeSource.getTime(),
           preferredOp, now.toEpochMilli()))) {
         lastRunAt = nextRunTime; // set to nextRunTime instead of now to avoid drift
       }

solr/core/src/java/org/apache/solr/cloud/autoscaling/ScheduledTriggers.java

@@ -148,6 +148,10 @@ public class ScheduledTriggers implements Closeable {
     if (this.autoScalingConfig != null) {
       currentProps.putAll(this.autoScalingConfig.getProperties());
     }
+
+    // reset listeners early in order to capture first execution of newly scheduled triggers
+    listeners.setAutoScalingConfig(autoScalingConfig);
+
     for (Map.Entry<String, Object> entry : currentProps.entrySet()) {
       Map<String, Object> newProps = autoScalingConfig.getProperties();
       String key = entry.getKey();
@@ -178,12 +182,10 @@ public class ScheduledTriggers implements Closeable {
         }
       }
     }
-    this.autoScalingConfig = autoScalingConfig;
 
+    this.autoScalingConfig = autoScalingConfig;
     // reset cooldown
     cooldownStart.set(cloudManager.getTimeSource().getTime() - cooldownPeriod.get());
-
-    listeners.setAutoScalingConfig(autoScalingConfig);
   }
 
   /**
@@ -226,16 +228,17 @@ public class ScheduledTriggers implements Closeable {
       scheduledTriggerWrappers.replace(newTrigger.getName(), triggerWrapper);
     }
     newTrigger.setProcessor(event -> {
+      TriggerListeners triggerListeners = listeners.copy();
       if (cloudManager.isClosed()) {
         String msg = String.format(Locale.ROOT, "Ignoring autoscaling event %s because Solr has been shutdown.", event.toString());
         log.warn(msg);
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.ABORTED, msg);
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.ABORTED, msg);
         return false;
       }
       TriggerWrapper scheduledSource = scheduledTriggerWrappers.get(event.getSource());
       if (scheduledSource == null) {
         String msg = String.format(Locale.ROOT, "Ignoring autoscaling event %s because the source trigger: %s doesn't exist.", event.toString(), event.getSource());
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.FAILED, msg);
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.FAILED, msg);
         log.warn(msg);
         return false;
       }
@@ -243,7 +246,7 @@ public class ScheduledTriggers implements Closeable {
       AutoScaling.Trigger source = scheduledSource.trigger;
       if (scheduledSource.isClosed || source.isClosed()) {
         String msg = String.format(Locale.ROOT, "Ignoring autoscaling event %s because the source trigger: %s has already been closed", event.toString(), source);
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.ABORTED, msg);
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.ABORTED, msg);
         log.warn(msg);
         // we do not want to lose this event just because the trigger was closed, perhaps a replacement will need it
         return false;
@@ -251,7 +254,7 @@ public class ScheduledTriggers implements Closeable {
       if (event.isIgnored())  {
         log.debug("-------- Ignoring event: " + event);
         event.getProperties().put(TriggerEvent.IGNORED, true);
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.IGNORED, "Event was ignored.");
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.IGNORED, "Event was ignored.");
         return true; // always return true for ignored events
       }
       // even though we pause all triggers during action execution there is a possibility that a trigger was already
@@ -259,7 +262,7 @@ public class ScheduledTriggers implements Closeable {
       if (cooldownStart.get() + cooldownPeriod.get() > cloudManager.getTimeSource().getTime()) {
         log.debug("-------- Cooldown period - rejecting event: " + event);
         event.getProperties().put(TriggerEvent.COOLDOWN, true);
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.IGNORED, "In cooldown period.");
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.IGNORED, "In cooldown period.");
         return false;
       } else {
         log.debug("++++++++ Cooldown inactive - processing event: " + event);
@@ -275,12 +278,12 @@ public class ScheduledTriggers implements Closeable {
           enqueued = triggerWrapper.enqueue(event);
         }
         // fire STARTED event listeners after enqueuing the event is successful
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.STARTED);
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.STARTED);
         List<TriggerAction> actions = source.getActions();
         if (actions != null) {
           if (actionExecutor.isShutdown()) {
             String msg = String.format(Locale.ROOT, "Ignoring autoscaling event %s from trigger %s because the executor has already been closed", event.toString(), source);
-            listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.ABORTED, msg);
+            triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.ABORTED, msg);
             log.warn(msg);
             // we do not want to lose this event just because the trigger was closed, perhaps a replacement will need it
             return false;
@@ -288,6 +291,7 @@ public class ScheduledTriggers implements Closeable {
           actionExecutor.submit(() -> {
             assert hasPendingActions.get();
             long eventProcessingStart = cloudManager.getTimeSource().getTime();
+            TriggerListeners triggerListeners1 = triggerListeners.copy();
             log.debug("-- processing actions for " + event);
             try {
               // in future, we could wait for pending tasks in a different thread and re-enqueue
@@ -298,22 +302,22 @@ public class ScheduledTriggers implements Closeable {
               for (TriggerAction action : actions) {
                 List<String> beforeActions = (List<String>) actionContext.getProperties().computeIfAbsent(TriggerEventProcessorStage.BEFORE_ACTION.toString(), k -> new ArrayList<String>());
                 beforeActions.add(action.getName());
-                listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.BEFORE_ACTION, action.getName(), actionContext);
+                triggerListeners1.fireListeners(event.getSource(), event, TriggerEventProcessorStage.BEFORE_ACTION, action.getName(), actionContext);
                 try {
                   action.process(event, actionContext);
                 } catch (Exception e) {
-                  listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.FAILED, action.getName(), actionContext, e, null);
+                  triggerListeners1.fireListeners(event.getSource(), event, TriggerEventProcessorStage.FAILED, action.getName(), actionContext, e, null);
                   throw new Exception("Error executing action: " + action.getName() + " for trigger event: " + event, e);
                 }
                 List<String> afterActions = (List<String>) actionContext.getProperties().computeIfAbsent(TriggerEventProcessorStage.AFTER_ACTION.toString(), k -> new ArrayList<String>());
                 afterActions.add(action.getName());
-                listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.AFTER_ACTION, action.getName(), actionContext);
+                triggerListeners1.fireListeners(event.getSource(), event, TriggerEventProcessorStage.AFTER_ACTION, action.getName(), actionContext);
               }
               if (enqueued) {
                 TriggerEvent ev = triggerWrapper.dequeue();
                 assert ev.getId().equals(event.getId());
               }
-              listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.SUCCEEDED);
+              triggerListeners1.fireListeners(event.getSource(), event, TriggerEventProcessorStage.SUCCEEDED);
             } catch (Exception e) {
               log.warn("Exception executing actions", e);
             } finally {
@@ -333,7 +337,7 @@ public class ScheduledTriggers implements Closeable {
               + " is broken! Expected event=" + event + " but got " + ev);
             }
           }
-          listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.SUCCEEDED);
+          triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.SUCCEEDED);
           hasPendingActions.set(false);
           // resume triggers now
           resumeTriggers(0);
@@ -341,7 +345,7 @@ public class ScheduledTriggers implements Closeable {
         return true;
       } else {
         // there is an action in the queue and we don't want to enqueue another until it is complete
-        listeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.IGNORED, "Already processing another event.");
+        triggerListeners.fireListeners(event.getSource(), event, TriggerEventProcessorStage.IGNORED, "Already processing another event.");
         return false;
       }
     });
@@ -596,6 +600,27 @@ public class ScheduledTriggers implements Closeable {
     Map<String, TriggerListener> listenersPerName = new HashMap<>();
     ReentrantLock updateLock = new ReentrantLock();
 
+    public TriggerListeners() {
+
+    }
+
+    private TriggerListeners(Map<String, Map<TriggerEventProcessorStage, List<TriggerListener>>> listenersPerStage,
+                             Map<String, TriggerListener> listenersPerName) {
+      this.listenersPerStage = new HashMap<>();
+      listenersPerStage.forEach((n, listeners) -> {
+        Map<TriggerEventProcessorStage, List<TriggerListener>> perStage = this.listenersPerStage.computeIfAbsent(n, name -> new HashMap<>());
+        listeners.forEach((s, lst) -> {
+          List<TriggerListener> newLst = perStage.computeIfAbsent(s, stage -> new ArrayList<>());
+          newLst.addAll(lst);
+        });
+      });
+      this.listenersPerName = new HashMap<>(listenersPerName);
+    }
+
+    public TriggerListeners copy() {
+      return new TriggerListeners(listenersPerStage, listenersPerName);
+    }
+
     void setAutoScalingConfig(AutoScalingConfig autoScalingConfig) {
       updateLock.lock();
       // we will recreate this from scratch

solr/core/src/java/org/apache/solr/cloud/overseer/SliceMutator.java

@@ -178,6 +178,8 @@ public class SliceMutator {
         props.remove("shard_parent_zk_session");
       }
       props.put(ZkStateReader.STATE_PROP, message.getStr(key));
+      // we need to use epoch time so that it's comparable across Overseer restarts
+      props.put(ZkStateReader.STATE_TIMESTAMP_PROP, String.valueOf(dataProvider.getTimeSource().getEpochTime()));
       Slice newSlice = new Slice(slice.getName(), slice.getReplicasCopy(), props);
       slicesCopy.put(slice.getName(), newSlice);
     }

solr/core/src/test/org/apache/solr/cloud/ActionThrottleTest.java

@@ -40,6 +40,11 @@ public class ActionThrottleTest extends SolrTestCaseJ4 {
       return returnValues.get(index++);
     }
 
+    @Override
+    public long getEpochTime() {
+      return getTime();
+    }
+
     @Override
     public void sleep(long ms) throws InterruptedException {
       throw new UnsupportedOperationException();

solr/core/src/test/org/apache/solr/cloud/CloudTestUtils.java

@@ -0,0 +1,133 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.cloud;
+
+import java.io.IOException;
+import java.lang.invoke.MethodHandles;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.apache.solr.client.solrj.cloud.autoscaling.SolrCloudManager;
+import org.apache.solr.common.cloud.ClusterState;
+import org.apache.solr.common.cloud.CollectionStatePredicate;
+import org.apache.solr.common.cloud.DocCollection;
+import org.apache.solr.common.cloud.Replica;
+import org.apache.solr.common.cloud.Slice;
+import org.apache.solr.util.TimeOut;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Some useful methods for SolrCloud tests.
+ */
+public class CloudTestUtils {
+  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  public static final int DEFAULT_TIMEOUT = 90;
+
+  /**
+   * Wait for a particular collection state to appear.
+   *
+   * This is a convenience method using the {@link #DEFAULT_TIMEOUT}
+   *
+   * @param cloudManager current instance of {@link SolrCloudManager}
+   * @param message     a message to report on failure
+   * @param collection  the collection to watch
+   * @param predicate   a predicate to match against the collection state
+   */
+  public static long waitForState(final SolrCloudManager cloudManager,
+                                  final String message,
+                                  final String collection,
+                                  final CollectionStatePredicate predicate) {
+    AtomicReference<DocCollection> state = new AtomicReference<>();
+    AtomicReference<Set<String>> liveNodesLastSeen = new AtomicReference<>();
+    try {
+      return waitForState(cloudManager, collection, DEFAULT_TIMEOUT, TimeUnit.SECONDS, (n, c) -> {
+        state.set(c);
+        liveNodesLastSeen.set(n);
+        return predicate.matches(n, c);
+      });
+    } catch (Exception e) {
+      throw new AssertionError(message + "\n" + "Live Nodes: " + liveNodesLastSeen.get() + "\nLast available state: " + state.get(), e);
+    }
+  }
+
+  /**
+   * Wait for a particular collection state to appear.
+   *
+   * This is a convenience method using the {@link #DEFAULT_TIMEOUT}
+   *
+   * @param cloudManager current instance of {@link SolrCloudManager}
+   * @param collection  the collection to watch
+   * @param wait timeout value
+   * @param unit timeout unit
+   * @param predicate   a predicate to match against the collection state
+   */
+  public static long waitForState(final SolrCloudManager cloudManager,
+                                  final String collection,
+                                  long wait,
+                                  final TimeUnit unit,
+                                  final CollectionStatePredicate predicate) throws InterruptedException, TimeoutException, IOException {
+    TimeOut timeout = new TimeOut(wait, unit, cloudManager.getTimeSource());
+    long timeWarn = timeout.timeLeft(TimeUnit.MILLISECONDS) / 4;
+    while (!timeout.hasTimedOut()) {
+      ClusterState state = cloudManager.getClusterStateProvider().getClusterState();
+      DocCollection coll = state.getCollectionOrNull(collection);
+      // due to the way we manage collections in SimClusterStateProvider a null here
+      // can mean that a collection is still being created but has no replicas
+      if (coll == null) { // does not yet exist?
+        timeout.sleep(50);
+        continue;
+      }
+      if (predicate.matches(state.getLiveNodes(), coll)) {
+        log.trace("-- predicate matched with state {}", state);
+        return timeout.timeElapsed(TimeUnit.MILLISECONDS);
+      }
+      timeout.sleep(50);
+      if (timeout.timeLeft(TimeUnit.MILLISECONDS) < timeWarn) {
+        log.trace("-- still not matching predicate: {}", state);
+      }
+    }
+    throw new TimeoutException();
+  }
+
+  /**
+   * Return a {@link CollectionStatePredicate} that returns true if a collection has the expected
+   * number of shards and replicas
+   */
+  public static CollectionStatePredicate clusterShape(int expectedShards, int expectedReplicas) {
+    return (liveNodes, collectionState) -> {
+      if (collectionState == null)
+        return false;
+      if (collectionState.getSlices().size() != expectedShards)
+        return false;
+      for (Slice slice : collectionState) {
+        int activeReplicas = 0;
+        for (Replica replica : slice) {
+          if (replica.isActive(liveNodes))
+            activeReplicas++;
+        }
+        if (activeReplicas != expectedReplicas)
+          return false;
+      }
+      return true;
+    };
+  }
+}

solr/core/src/test/org/apache/solr/cloud/autoscaling/ScheduledMaintenanceTriggerTest.java

@@ -0,0 +1,234 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.cloud.autoscaling;
+
+import java.lang.invoke.MethodHandles;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.solr.client.solrj.SolrClient;
+import org.apache.solr.client.solrj.SolrRequest;
+import org.apache.solr.client.solrj.cloud.autoscaling.AutoScalingConfig;
+import org.apache.solr.client.solrj.cloud.autoscaling.SolrCloudManager;
+import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventProcessorStage;
+import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.CloudTestUtils;
+import org.apache.solr.cloud.SolrCloudTestCase;
+import org.apache.solr.cloud.autoscaling.sim.SimCloudManager;
+import org.apache.solr.common.cloud.ClusterState;
+import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.TimeSource;
+import org.apache.solr.util.LogLevel;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.apache.solr.cloud.autoscaling.AutoScalingHandlerTest.createAutoScalingRequest;
+
+/**
+ *
+ */
+@LogLevel("org.apache.solr.cloud.autoscaling=DEBUG")
+public class ScheduledMaintenanceTriggerTest extends SolrCloudTestCase {
+  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  private static SolrCloudManager cloudManager;
+  private static SolrClient solrClient;
+  private static TimeSource timeSource;
+
+  @BeforeClass
+  public static void setupCluster() throws Exception {
+    configureCluster(1)
+        .addConfig("conf", configset("cloud-minimal"))
+        .configure();
+    if (random().nextBoolean()) {
+      cloudManager = cluster.getJettySolrRunner(0).getCoreContainer().getZkController().getSolrCloudManager();
+      solrClient = cluster.getSolrClient();
+    } else {
+      cloudManager = SimCloudManager.createCluster(1, TimeSource.get("simTime:50"));
+      solrClient = ((SimCloudManager)cloudManager).simGetSolrClient();
+    }
+    timeSource = cloudManager.getTimeSource();
+  }
+
+  @After
+  public void restoreDefaults() throws Exception {
+    SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST,
+        "{'set-trigger' : " + AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_DSL + "}");
+    NamedList<Object> response = solrClient.request(req);
+    assertEquals(response.get("result").toString(), "success");
+    AutoScalingConfig autoScalingConfig = cloudManager.getDistribStateManager().getAutoScalingConfig();
+    if (autoScalingConfig.getTriggerListenerConfigs().containsKey("foo")) {
+      String cmd = "{" +
+          "'remove-listener' : {'name' : 'foo'}" +
+          "}";
+      response = solrClient.request(createAutoScalingRequest(SolrRequest.METHOD.POST, cmd));
+      assertEquals(response.get("result").toString(), "success");
+    }
+  }
+
+  @AfterClass
+  public static void teardown() throws Exception {
+    if (cloudManager instanceof SimCloudManager) {
+      cloudManager.close();
+    }
+    solrClient = null;
+    cloudManager = null;
+  }
+
+  @Test
+  public void testTriggerDefaults() throws Exception {
+    AutoScalingConfig autoScalingConfig = cloudManager.getDistribStateManager().getAutoScalingConfig();
+    log.info(autoScalingConfig.toString());
+    AutoScalingConfig.TriggerConfig triggerConfig = autoScalingConfig.getTriggerConfigs().get(AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_NAME);
+    assertNotNull(triggerConfig);
+    assertEquals(2, triggerConfig.actions.size());
+    assertTrue(triggerConfig.actions.get(0).actionClass.endsWith(InactiveShardPlanAction.class.getSimpleName()));
+    assertTrue(triggerConfig.actions.get(1).actionClass.endsWith(ExecutePlanAction.class.getSimpleName()));
+    AutoScalingConfig.TriggerListenerConfig listenerConfig = autoScalingConfig.getTriggerListenerConfigs().get(AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_NAME + ".system");
+    assertNotNull(listenerConfig);
+    assertEquals(AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_NAME, listenerConfig.trigger);
+    assertTrue(listenerConfig.listenerClass.endsWith(SystemLogListener.class.getSimpleName()));
+  }
+
+  static Map<String, List<CapturedEvent>> listenerEvents = new ConcurrentHashMap<>();
+  static CountDownLatch listenerCreated = new CountDownLatch(1);
+
+  public static class CapturingTriggerListener extends TriggerListenerBase {
+    @Override
+    public void init(SolrCloudManager cloudManager, AutoScalingConfig.TriggerListenerConfig config) {
+      super.init(cloudManager, config);
+      listenerCreated.countDown();
+    }
+
+    @Override
+    public synchronized void onEvent(TriggerEvent event, TriggerEventProcessorStage stage, String actionName,
+                                     ActionContext context, Throwable error, String message) {
+      List<CapturedEvent> lst = listenerEvents.computeIfAbsent(config.name, s -> new ArrayList<>());
+      CapturedEvent ev = new CapturedEvent(timeSource.getTime(), context, config, stage, actionName, event, message);
+      log.info("=======> " + ev);
+      lst.add(ev);
+    }
+  }
+
+  static CountDownLatch triggerFired = new CountDownLatch(1);
+
+  public static class TestTriggerAction extends TriggerActionBase {
+
+    @Override
+    public void process(TriggerEvent event, ActionContext context) throws Exception {
+      if (context.getProperties().containsKey("inactive_shard_plan")) {
+        triggerFired.countDown();
+      }
+    }
+  }
+
+  @Test
+  public void testInactiveShardCleanup() throws Exception {
+    String collection1 = getClass().getSimpleName() + "_collection1";
+    CollectionAdminRequest.Create create1 = CollectionAdminRequest.createCollection(collection1,
+        "conf", 1, 1);
+
+    create1.process(solrClient);
+    CloudTestUtils.waitForState(cloudManager, "failed to create " + collection1, collection1,
+        CloudTestUtils.clusterShape(1, 1));
+
+    CollectionAdminRequest.SplitShard split1 = CollectionAdminRequest.splitShard(collection1)
+        .setShardName("shard1");
+    split1.process(solrClient);
+    CloudTestUtils.waitForState(cloudManager, "failed to split " + collection1, collection1,
+        CloudTestUtils.clusterShape(3, 1));
+
+    String setListenerCommand = "{" +
+        "'set-listener' : " +
+        "{" +
+        "'name' : 'foo'," +
+        "'trigger' : '" + AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_NAME + "'," +
+        "'stage' : ['STARTED','ABORTED','SUCCEEDED','FAILED']," +
+        "'beforeAction' : 'inactive_shard_plan'," +
+        "'afterAction' : 'inactive_shard_plan'," +
+        "'class' : '" + CapturingTriggerListener.class.getName() + "'" +
+        "}" +
+        "}";
+    SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST, setListenerCommand);
+    NamedList<Object> response = solrClient.request(req);
+    assertEquals(response.get("result").toString(), "success");
+
+    String setTriggerCommand = "{" +
+        "'set-trigger' : {" +
+        "'name' : '" + AutoScaling.SCHEDULED_MAINTENANCE_TRIGGER_NAME + "'," +
+        "'event' : 'scheduled'," +
+        "'startTime' : 'NOW+3SECONDS'," +
+        "'every' : '+2SECONDS'," +
+        "'enabled' : true," +
+        "'actions' : [{'name' : 'inactive_shard_plan', 'class' : 'solr.InactiveShardPlanAction', 'ttl' : '10'}," +
+        "{'name' : 'execute_plan', 'class' : '" + ExecutePlanAction.class.getName() + "'}," +
+        "{'name' : 'test', 'class' : '" + TestTriggerAction.class.getName() + "'}]" +
+        "}}";
+    req = createAutoScalingRequest(SolrRequest.METHOD.POST, setTriggerCommand);
+    response = solrClient.request(req);
+    assertEquals(response.get("result").toString(), "success");
+
+    boolean await = listenerCreated.await(10, TimeUnit.SECONDS);
+    assertTrue("listener not created in time", await);
+    await = triggerFired.await(60, TimeUnit.SECONDS);
+    assertTrue("cleanup action didn't run", await);
+
+    // cleanup should have occurred
+    assertFalse("no events captured!", listenerEvents.isEmpty());
+    List<CapturedEvent> events = new ArrayList<>(listenerEvents.get("foo"));
+    listenerEvents.clear();
+
+    assertFalse(events.isEmpty());
+    int inactiveEvents = 0;
+    CapturedEvent ce = null;
+    for (CapturedEvent e : events) {
+      if (e.stage != TriggerEventProcessorStage.AFTER_ACTION) {
+        continue;
+      }
+      if (e.context.containsKey("properties.inactive_shard_plan")) {
+        ce = e;
+        break;
+      } else {
+        inactiveEvents++;
+      }
+    }
+    assertTrue("should be at least one inactive event", inactiveEvents > 0);
+    assertNotNull("missing cleanup event", ce);
+    Map<String, Object> map = (Map<String, Object>)ce.context.get("properties.inactive_shard_plan");
+    assertNotNull(map);
+
+    Map<String, List<String>> inactive = (Map<String, List<String>>)map.get("inactive");
+    assertEquals(1, inactive.size());
+    assertNotNull(inactive.get(collection1));
+    Map<String, List<String>> cleanup = (Map<String, List<String>>)map.get("cleanup");
+    assertEquals(1, cleanup.size());
+    assertNotNull(cleanup.get(collection1));
+
+    ClusterState state = cloudManager.getClusterStateProvider().getClusterState();
+
+    CloudTestUtils.clusterShape(2, 1).matches(state.getLiveNodes(), state.getCollection(collection1));
+  }
+}

solr/core/src/test/org/apache/solr/cloud/autoscaling/TriggerIntegrationTest.java

@@ -36,6 +36,7 @@ import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantLock;
 
 import com.google.common.util.concurrent.AtomicDouble;
+import org.apache.solr.client.solrj.SolrClient;
 import org.apache.solr.client.solrj.SolrRequest;
 import org.apache.solr.client.solrj.cloud.autoscaling.AutoScalingConfig;
 import org.apache.solr.client.solrj.cloud.autoscaling.ReplicaInfo;
@@ -105,6 +106,14 @@ public class TriggerIntegrationTest extends SolrCloudTestCase {
         .addConfig("conf", configset("cloud-minimal"))
         .configure();
     zkStateReader = cluster.getSolrClient().getZkStateReader();
+    // disable .scheduled_maintenance
+    String suspendTriggerCommand = "{" +
+        "'suspend-trigger' : {'name' : '.scheduled_maintenance'}" +
+        "}";
+    SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST, suspendTriggerCommand);
+    SolrClient solrClient = cluster.getSolrClient();
+    NamedList<Object> response = solrClient.request(req);
+    assertEquals(response.get("result").toString(), "success");
   }
 
   private static CountDownLatch getTriggerFiredLatch() {

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/SimCloudManager.java

@@ -496,6 +496,7 @@ public class SimCloudManager implements SolrCloudManager {
       SolrQueryResponse queryResponse = new SolrQueryResponse();
       autoScalingHandler.handleRequest(queryRequest, queryResponse);
       if (queryResponse.getException() != null) {
+        LOG.debug("-- exception handling request", queryResponse.getException());
         throw new IOException(queryResponse.getException());
       }
       SolrResponse rsp = new SolrResponseBase();
@@ -608,6 +609,13 @@ public class SimCloudManager implements SolrCloudManager {
             throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, e);
           }
           break;
+        case DELETESHARD:
+          try {
+            clusterStateProvider.simDeleteShard(new ZkNodeProps(req.getParams().toNamedList().asMap(10)), results);
+          } catch (Exception e) {
+            throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, e);
+          }
+          break;
         default:
           throw new UnsupportedOperationException("Unsupported collection admin action=" + action + " in request: " + req.getParams());
       }

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/SimClusterStateProvider.java

@@ -358,13 +358,13 @@ public class SimClusterStateProvider implements ClusterStateProvider {
    * @param runLeaderElection if true then run a leader election after adding the replica.
    */
   public void simAddReplica(String nodeId, ReplicaInfo replicaInfo, boolean runLeaderElection) throws Exception {
-    // make sure coreNodeName is unique across cluster
+    // make sure SolrCore name is unique across cluster and coreNodeName within collection
     for (Map.Entry<String, List<ReplicaInfo>> e : nodeReplicaMap.entrySet()) {
       for (ReplicaInfo ri : e.getValue()) {
         if (ri.getCore().equals(replicaInfo.getCore())) {
           throw new Exception("Duplicate SolrCore name for existing=" + ri + " on node " + e.getKey() + " and new=" + replicaInfo);
         }
-        if (ri.getName().equals(replicaInfo.getName())) {
+        if (ri.getName().equals(replicaInfo.getName()) && ri.getCollection().equals(replicaInfo.getCollection())) {
           throw new Exception("Duplicate coreNode name for existing=" + ri + " on node " + e.getKey() + " and new=" + replicaInfo);
         }
       }
@@ -857,6 +857,9 @@ public class SimClusterStateProvider implements ClusterStateProvider {
    * @param results operation results.
    */
   public void simSplitShard(ZkNodeProps message, NamedList results) throws Exception {
+    if (message.getStr(CommonAdminParams.ASYNC) != null) {
+      results.add(CoreAdminParams.REQUESTID, message.getStr(CommonAdminParams.ASYNC));
+    }
     String collectionName = message.getStr(COLLECTION_PROP);
     AtomicReference<String> sliceName = new AtomicReference<>();
     sliceName.set(message.getStr(SHARD_ID_PROP));
@@ -871,20 +874,6 @@ public class SimClusterStateProvider implements ClusterStateProvider {
     opDelay(collectionName, CollectionParams.CollectionAction.SPLITSHARD.name());
 
     SplitShardCmd.fillRanges(cloudManager, message, collection, parentSlice, subRanges, subSlices, subShardNames);
-    // mark the old slice as inactive
-    sliceProperties.computeIfAbsent(collectionName, c -> new ConcurrentHashMap<>())
-        .computeIfAbsent(sliceName.get(), s -> new ConcurrentHashMap<>())
-        .put(ZkStateReader.SHARD_STATE_PROP, Slice.State.INACTIVE.toString());
-    // add slice props
-    for (int i = 0; i < subRanges.size(); i++) {
-      String subSlice = subSlices.get(i);
-      DocRouter.Range range = subRanges.get(i);
-      Map<String, Object> sliceProps = sliceProperties.computeIfAbsent(collectionName, c -> new ConcurrentHashMap<>())
-          .computeIfAbsent(subSlice, ss -> new ConcurrentHashMap<>());
-      sliceProps.put(Slice.RANGE, range);
-      sliceProps.put(Slice.PARENT, sliceName.get());
-      sliceProps.put(ZkStateReader.SHARD_STATE_PROP, Slice.State.ACTIVE.toString());
-    }
     // add replicas for new subShards
     int repFactor = parentSlice.getReplicas().size();
     List<ReplicaPosition> replicaPositions = Assign.identifyNodes(cloudManager,
@@ -911,6 +900,22 @@ public class SimClusterStateProvider implements ClusterStateProvider {
           solrCoreName, collectionName, replicaPosition.shard, replicaPosition.type, subShardNodeName, replicaProps);
       simAddReplica(replicaPosition.node, ri, false);
     }
+    // mark the old slice as inactive
+    Map<String, Object> props = sliceProperties.computeIfAbsent(collectionName, c -> new ConcurrentHashMap<>())
+        .computeIfAbsent(sliceName.get(), s -> new ConcurrentHashMap<>());
+    props.put(ZkStateReader.STATE_PROP, Slice.State.INACTIVE.toString());
+    props.put(ZkStateReader.STATE_TIMESTAMP_PROP, String.valueOf(cloudManager.getTimeSource().getEpochTime()));
+    // add slice props
+    for (int i = 0; i < subRanges.size(); i++) {
+      String subSlice = subSlices.get(i);
+      DocRouter.Range range = subRanges.get(i);
+      Map<String, Object> sliceProps = sliceProperties.computeIfAbsent(collectionName, c -> new ConcurrentHashMap<>())
+          .computeIfAbsent(subSlice, ss -> new ConcurrentHashMap<>());
+      sliceProps.put(Slice.RANGE, range);
+      sliceProps.put(Slice.PARENT, sliceName.get());
+      sliceProps.put(ZkStateReader.STATE_PROP, Slice.State.ACTIVE.toString());
+      props.put(ZkStateReader.STATE_TIMESTAMP_PROP, String.valueOf(cloudManager.getTimeSource().getEpochTime()));
+    }
     simRunLeaderElection(Collections.singleton(collectionName), true);
     results.add("success", "");
 
@@ -922,6 +927,9 @@ public class SimClusterStateProvider implements ClusterStateProvider {
    * @param results operation results
    */
   public void simDeleteShard(ZkNodeProps message, NamedList results) throws Exception {
+    if (message.getStr(CommonAdminParams.ASYNC) != null) {
+      results.add(CoreAdminParams.REQUESTID, message.getStr(CommonAdminParams.ASYNC));
+    }
     String collectionName = message.getStr(COLLECTION_PROP);
     String sliceName = message.getStr(SHARD_ID_PROP);
     ClusterState clusterState = getClusterState();

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/SimSolrCloudTestCase.java

@@ -26,16 +26,11 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Predicate;
 
 import org.apache.solr.SolrTestCaseJ4;
 import org.apache.solr.client.solrj.cloud.autoscaling.ReplicaInfo;
-import org.apache.solr.common.cloud.ClusterState;
-import org.apache.solr.common.cloud.CollectionStatePredicate;
 import org.apache.solr.common.cloud.DocCollection;
 import org.apache.solr.common.cloud.Replica;
 import org.apache.solr.common.cloud.Slice;
@@ -43,7 +38,6 @@ import org.apache.solr.common.cloud.ZkNodeProps;
 import org.apache.solr.common.cloud.ZkStateReader;
 import org.apache.solr.common.util.TimeSource;
 import org.apache.solr.common.util.Utils;
-import org.apache.solr.util.TimeOut;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.slf4j.Logger;
@@ -64,8 +58,6 @@ import static org.apache.solr.common.cloud.ZkStateReader.SOLR_AUTOSCALING_CONF_P
 public class SimSolrCloudTestCase extends SolrTestCaseJ4 {
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
 
-  public static final int DEFAULT_TIMEOUT = 90;
-
   /** The cluster. */
   protected static SimCloudManager cluster;
   protected static int clusterNodeCount = 0;
@@ -198,92 +190,6 @@ public class SimSolrCloudTestCase extends SolrTestCaseJ4 {
     return cluster.getClusterStateProvider().getClusterState().getCollection(collectionName);
   }
 
-  /**
-   * Wait for a particular collection state to appear in the cluster client's state reader
-   *
-   * This is a convenience method using the {@link #DEFAULT_TIMEOUT}
-   *
-   * @param message     a message to report on failure
-   * @param collection  the collection to watch
-   * @param predicate   a predicate to match against the collection state
-   */
-  protected long waitForState(String message, String collection, CollectionStatePredicate predicate) {
-    AtomicReference<DocCollection> state = new AtomicReference<>();
-    AtomicReference<Set<String>> liveNodesLastSeen = new AtomicReference<>();
-    try {
-      return waitForState(collection, DEFAULT_TIMEOUT, TimeUnit.SECONDS, (n, c) -> {
-        state.set(c);
-        liveNodesLastSeen.set(n);
-        return predicate.matches(n, c);
-      });
-    } catch (Exception e) {
-      throw new AssertionError(message + "\n" + "Live Nodes: " + liveNodesLastSeen.get() + "\nLast available state: " + state.get(), e);
-    }
-  }
-
-  /**
-   * Block until a CollectionStatePredicate returns true, or the wait times out
-   *
-   * Note that the predicate may be called again even after it has returned true, so
-   * implementors should avoid changing state within the predicate call itself.
-   *
-   * @param collection the collection to watch
-   * @param wait       how long to wait
-   * @param unit       the units of the wait parameter
-   * @param predicate  the predicate to call on state changes
-   * @return number of milliseconds elapsed
-   * @throws InterruptedException on interrupt
-   * @throws TimeoutException on timeout
-   * @throws IOException on watcher register / unregister error
-   */
-  public long waitForState(final String collection, long wait, TimeUnit unit, CollectionStatePredicate predicate)
-      throws InterruptedException, TimeoutException, IOException {
-    TimeOut timeout = new TimeOut(wait, unit, cluster.getTimeSource());
-    long timeWarn = timeout.timeLeft(TimeUnit.MILLISECONDS) / 4;
-    while (!timeout.hasTimedOut()) {
-      ClusterState state = cluster.getClusterStateProvider().getClusterState();
-      DocCollection coll = state.getCollectionOrNull(collection);
-      // due to the way we manage collections in SimClusterStateProvider a null here
-      // can mean that a collection is still being created but has no replicas
-      if (coll == null) { // does not yet exist?
-        timeout.sleep(50);
-        continue;
-      }
-      if (predicate.matches(state.getLiveNodes(), coll)) {
-        log.trace("-- predicate matched with state {}", state);
-        return timeout.timeElapsed(TimeUnit.MILLISECONDS);
-      }
-      timeout.sleep(50);
-      if (timeout.timeLeft(TimeUnit.MILLISECONDS) < timeWarn) {
-        log.trace("-- still not matching predicate: {}", state);
-      }
-    }
-    throw new TimeoutException();
-  }
-
-  /**
-   * Return a {@link CollectionStatePredicate} that returns true if a collection has the expected
-   * number of shards and replicas
-   */
-  public static CollectionStatePredicate clusterShape(int expectedShards, int expectedReplicas) {
-    return (liveNodes, collectionState) -> {
-      if (collectionState == null)
-        return false;
-      if (collectionState.getSlices().size() != expectedShards)
-        return false;
-      for (Slice slice : collectionState) {
-        int activeReplicas = 0;
-        for (Replica replica : slice) {
-          if (replica.isActive(liveNodes))
-            activeReplicas++;
-        }
-        if (activeReplicas != expectedReplicas)
-          return false;
-      }
-      return true;
-    };
-  }
-
   /**
    * Get a (reproducibly) random shard from a {@link DocCollection}
    */

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/TestComputePlanAction.java

@@ -32,6 +32,7 @@ import org.apache.solr.client.solrj.SolrRequest;
 import org.apache.solr.client.solrj.SolrResponse;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventType;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.CloudTestUtils;
 import org.apache.solr.cloud.autoscaling.ActionContext;
 import org.apache.solr.cloud.autoscaling.ComputePlanAction;
 import org.apache.solr.cloud.autoscaling.ScheduledTriggers;
@@ -141,8 +142,8 @@ public class TestComputePlanAction extends SimSolrCloudTestCase {
         "conf",1, 2);
     create.process(solrClient);
 
-    waitForState("Timed out waiting for replicas of new collection to be active",
+    CloudTestUtils.waitForState(cluster, "Timed out waiting for replicas of new collection to be active",
-        "testNodeLost", clusterShape(1, 2));
+        "testNodeLost", CloudTestUtils.clusterShape(1, 2));
 
     ClusterState clusterState = cluster.getClusterStateProvider().getClusterState();
     log.debug("-- cluster state: {}", clusterState);
@@ -204,8 +205,8 @@ public class TestComputePlanAction extends SimSolrCloudTestCase {
 //    create.setMaxShardsPerNode(2);
     create.process(solrClient);
 
-    waitForState("Timed out waiting for replicas of new collection to be active",
+    CloudTestUtils.waitForState(cluster, "Timed out waiting for replicas of new collection to be active",
-        "testNodeWithMultipleReplicasLost", clusterShape(2, 3));
+        "testNodeWithMultipleReplicasLost", CloudTestUtils.clusterShape(2, 3));
 
     ClusterState clusterState = cluster.getClusterStateProvider().getClusterState();
     log.debug("-- cluster state: {}", clusterState);
@@ -281,7 +282,7 @@ public class TestComputePlanAction extends SimSolrCloudTestCase {
         "conf",1, 2);
     create.process(solrClient);
 
-    waitForState("Timed out waiting for replicas of new collection to be active",
+    CloudTestUtils.waitForState(cluster, "Timed out waiting for replicas of new collection to be active",
         "testNodeAdded", (liveNodes, collectionState) -> collectionState.getReplicas().stream().allMatch(replica -> replica.isActive(liveNodes)));
 
     // reset to the original policy which has only 1 replica per shard per node

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/TestExecutePlanAction.java

@@ -32,6 +32,7 @@ import org.apache.solr.client.solrj.SolrRequest;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventType;
 import org.apache.solr.client.solrj.cloud.autoscaling.VersionedData;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.CloudTestUtils;
 import org.apache.solr.cloud.autoscaling.ActionContext;
 import org.apache.solr.cloud.autoscaling.AutoScalingHandlerTest;
 import org.apache.solr.cloud.autoscaling.ExecutePlanAction;
@@ -86,7 +87,8 @@ public class TestExecutePlanAction extends SimSolrCloudTestCase {
     create.setMaxShardsPerNode(1);
     create.process(solrClient);
 
-    log.info("Collection ready after " + waitForState(collectionName, 120, TimeUnit.SECONDS, clusterShape(1, 2)) + "ms");
+    log.info("Collection ready after " + CloudTestUtils.waitForState(cluster, collectionName, 120, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(1, 2)) + "ms");
 
     String sourceNodeName = cluster.getSimClusterStateProvider().simGetRandomNode(random());
     ClusterState clusterState = cluster.getClusterStateProvider().getClusterState();
@@ -147,7 +149,8 @@ public class TestExecutePlanAction extends SimSolrCloudTestCase {
       assertNotNull(response.get("success"));
     }
 
-    log.info("Collection ready after " + waitForState(collectionName, 300, TimeUnit.SECONDS, clusterShape(1, 2)) + "ms");
+    log.info("Collection ready after " + CloudTestUtils.waitForState(cluster, collectionName, 300, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(1, 2)) + "ms");
   }
 
   @Test
@@ -173,8 +176,8 @@ public class TestExecutePlanAction extends SimSolrCloudTestCase {
     create.setMaxShardsPerNode(1);
     create.process(solrClient);
 
-    waitForState("Timed out waiting for replicas of new collection to be active",
+    CloudTestUtils.waitForState(cluster, "Timed out waiting for replicas of new collection to be active",
-        collectionName, clusterShape(1, 2));
+        collectionName, CloudTestUtils.clusterShape(1, 2));
 
     String sourceNodeName = cluster.getSimClusterStateProvider().simGetRandomNode(random());
     ClusterState clusterState = cluster.getClusterStateProvider().getClusterState();
@@ -190,8 +193,8 @@ public class TestExecutePlanAction extends SimSolrCloudTestCase {
 
     cluster.simRemoveNode(sourceNodeName, false);
 
-    waitForState("Timed out waiting for replicas of collection to be 2 again",
+    CloudTestUtils.waitForState(cluster, "Timed out waiting for replicas of collection to be 2 again",
-        collectionName, clusterShape(1, 2));
+        collectionName, CloudTestUtils.clusterShape(1, 2));
 
     clusterState = cluster.getClusterStateProvider().getClusterState();
     docCollection = clusterState.getCollection(collectionName);

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/TestLargeCluster.java

@@ -40,6 +40,7 @@ import org.apache.solr.client.solrj.cloud.autoscaling.Suggester;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventProcessorStage;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventType;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.CloudTestUtils;
 import org.apache.solr.cloud.autoscaling.ActionContext;
 import org.apache.solr.cloud.autoscaling.ComputePlanAction;
 import org.apache.solr.cloud.autoscaling.ExecutePlanAction;
@@ -91,6 +92,14 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
     triggerFiredCount.set(0);
     triggerFiredLatch = new CountDownLatch(1);
     listenerEvents.clear();
+    // disable .scheduled_maintenance
+    String suspendTriggerCommand = "{" +
+        "'suspend-trigger' : {'name' : '.scheduled_maintenance'}" +
+        "}";
+    SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST, suspendTriggerCommand);
+    SolrClient solrClient = cluster.simGetSolrClient();
+    NamedList<Object> response = solrClient.request(req);
+    assertEquals(response.get("result").toString(), "success");
   }
 
   public static class TestTriggerListener extends TriggerListenerBase {
@@ -170,7 +179,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
     create.setCreateNodeSet(String.join(",", nodes));
     create.process(solrClient);
 
-    log.info("Ready after " + waitForState(collectionName, 30 * nodes.size(), TimeUnit.SECONDS, clusterShape(5, 15)) + "ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 30 * nodes.size(), TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(5, 15)) + "ms");
 
     int KILL_NODES = 8;
     // kill off a number of nodes
@@ -178,7 +188,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
       cluster.simRemoveNode(nodes.get(i), false);
     }
     // should fully recover
-    log.info("Ready after " + waitForState(collectionName, 90 * KILL_NODES, TimeUnit.SECONDS, clusterShape(5, 15)) + "ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 90 * KILL_NODES, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(5, 15)) + "ms");
 
     log.info("OP COUNTS: " + cluster.simGetOpCounts());
     long moveReplicaOps = cluster.simGetOpCount(CollectionParams.CollectionAction.MOVEREPLICA.name());
@@ -199,7 +210,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
       }
     }
 
-    log.info("Ready after " + waitForState(collectionName, 30 * nodes.size(), TimeUnit.SECONDS, clusterShape(5, 15)) + "ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 30 * nodes.size(), TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(5, 15)) + "ms");
     long newMoveReplicaOps = cluster.simGetOpCount(CollectionParams.CollectionAction.MOVEREPLICA.name());
     log.info("==== Flaky replicas: {}. Additional MOVEREPLICA count: {}", flakyReplicas, (newMoveReplicaOps - moveReplicaOps));
     // flaky nodes lead to a number of MOVEREPLICA that is non-zero but lower than the number of flaky replicas
@@ -219,7 +231,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
         "'enabled' : true," +
         "'actions' : [" +
         "{'name':'compute','class':'" + ComputePlanAction.class.getName() + "'}," +
-        "{'name':'execute','class':'" + ExecutePlanAction.class.getName() + "'}" +
+        "{'name':'execute','class':'" + ExecutePlanAction.class.getName() + "'}," +
+        "{'name':'test','class':'" + TestTriggerAction.class.getName() + "'}" +
         "]" +
         "}}";
     SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST, setTriggerCommand);
@@ -229,12 +242,13 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
     // create a collection with more than 1 replica per node
     String collectionName = "testNodeAdded";
     CollectionAdminRequest.Create create = CollectionAdminRequest.createCollection(collectionName,
-        "conf", NUM_NODES / 10, NUM_NODES / 10, NUM_NODES / 10, NUM_NODES / 10);
+        "conf", NUM_NODES / 10, NUM_NODES / 8, NUM_NODES / 8, NUM_NODES / 8);
     create.setMaxShardsPerNode(5);
     create.setAutoAddReplicas(false);
     create.process(solrClient);
 
-    log.info("Ready after " + waitForState(collectionName, 20 * NUM_NODES, TimeUnit.SECONDS, clusterShape(NUM_NODES / 10, NUM_NODES / 10 * 3)) + " ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 20 * NUM_NODES, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(NUM_NODES / 10, NUM_NODES / 8 * 3)) + " ms");
 
     int numAddNode = NUM_NODES / 5;
     List<String> addNodesList = new ArrayList<>(numAddNode);
@@ -242,6 +256,9 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
       addNodesList.add(cluster.simAddNode());
       cluster.getTimeSource().sleep(5000);
     }
+    boolean await = triggerFiredLatch.await(1000000 / SPEED, TimeUnit.MILLISECONDS);
+    assertTrue("trigger did not fire", await);
+
     List<SolrInputDocument> systemColl = cluster.simGetSystemCollection();
     int startedEventPos = -1;
     for (int i = 0; i < systemColl.size(); i++) {
@@ -261,7 +278,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
     // make sure some replicas have been moved
     assertTrue("no MOVEREPLICA ops?", cluster.simGetOpCount("MOVEREPLICA") > 0);
 
-    log.info("Ready after " + waitForState(collectionName, 20 * NUM_NODES, TimeUnit.SECONDS, clusterShape(NUM_NODES / 10, NUM_NODES / 10 * 3)) + " ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 20 * NUM_NODES, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(NUM_NODES / 10, NUM_NODES / 8 * 3)) + " ms");
 
     int count = 50;
     SolrInputDocument finishedEvent = null;
@@ -381,9 +399,9 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
         "'waitFor' : '" + waitFor + "s'," +
         "'enabled' : true," +
         "'actions' : [" +
-        "{'name':'test','class':'" + TestTriggerAction.class.getName() + "'}," +
         "{'name':'compute','class':'" + ComputePlanAction.class.getName() + "'}," +
-        "{'name':'execute','class':'" + ExecutePlanAction.class.getName() + "'}" +
+        "{'name':'execute','class':'" + ExecutePlanAction.class.getName() + "'}," +
+        "{'name':'test','class':'" + TestTriggerAction.class.getName() + "'}" +
         "]" +
         "}}";
     SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST, setTriggerCommand);
@@ -398,7 +416,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
     create.setAutoAddReplicas(false);
     create.process(solrClient);
 
-    log.info("Ready after " + waitForState(collectionName, 20 * NUM_NODES, TimeUnit.SECONDS, clusterShape(NUM_NODES / 5, NUM_NODES / 10)) + " ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 20 * NUM_NODES, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(NUM_NODES / 5, NUM_NODES / 10)) + " ms");
 
     // start killing nodes
     int numNodes = NUM_NODES / 5;
@@ -410,7 +429,7 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
       cluster.getTimeSource().sleep(killDelay);
     }
     // wait for the trigger to fire
-    boolean await = triggerFiredLatch.await(10 * waitFor * 1000 / SPEED, TimeUnit.MILLISECONDS);
+    boolean await = triggerFiredLatch.await(20 * waitFor * 1000 / SPEED, TimeUnit.MILLISECONDS);
     assertTrue("trigger did not fire within timeout, " +
         "waitFor=" + waitFor + ", killDelay=" + killDelay + ", minIgnored=" + minIgnored,
         await);
@@ -453,7 +472,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
             "waitFor=" + waitFor + ", killDelay=" + killDelay + ", minIgnored=" + minIgnored,
             cluster.simGetOpCount("MOVEREPLICA") > 0);
 
-    log.info("Ready after " + waitForState(collectionName, 20 * NUM_NODES, TimeUnit.SECONDS, clusterShape(NUM_NODES / 5, NUM_NODES / 10)) + " ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 20 * NUM_NODES, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(NUM_NODES / 5, NUM_NODES / 10)) + " ms");
 
     int count = 50;
     SolrInputDocument finishedEvent = null;
@@ -502,7 +522,8 @@ public class TestLargeCluster extends SimSolrCloudTestCase {
         "conf", 2, 10);
     create.process(solrClient);
 
-    log.info("Ready after " + waitForState(collectionName, 300, TimeUnit.SECONDS, clusterShape(2, 10)) + " ms");
+    log.info("Ready after " + CloudTestUtils.waitForState(cluster, collectionName, 300, TimeUnit.SECONDS,
+        CloudTestUtils.clusterShape(2, 10)) + " ms");
 
     // collect the node names for shard1
     Set<String> nodes = new HashSet<>();

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/TestPolicyCloud.java

@@ -35,6 +35,7 @@ import org.apache.solr.client.solrj.cloud.autoscaling.ReplicaInfo;
 import org.apache.solr.client.solrj.cloud.autoscaling.Row;
 import org.apache.solr.client.solrj.cloud.autoscaling.Suggestion;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.CloudTestUtils;
 import org.apache.solr.cloud.autoscaling.AutoScalingHandlerTest;
 import org.apache.solr.common.cloud.DocCollection;
 import org.apache.solr.common.cloud.Replica;
@@ -67,7 +68,8 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
     CollectionAdminRequest.createCollection("perReplicaDataColl", "conf", 1, 5)
         .process(solrClient);
 
-    waitForState("Timeout waiting for collection to become active", "perReplicaDataColl", clusterShape(1, 5));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", "perReplicaDataColl",
+        CloudTestUtils.clusterShape(1, 5));
     DocCollection coll = getCollectionState("perReplicaDataColl");
     String autoScaleJson = "{" +
         "  'cluster-preferences': [" +
@@ -116,12 +118,13 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
     CollectionAdminRequest.createCollection(collectionName, "conf", 1, 1)
         .setPolicy("c1")
         .process(solrClient);
-    waitForState("Timeout waiting for collection to become active", collectionName, clusterShape(1, 1));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", collectionName,
+        CloudTestUtils.clusterShape(1, 1));
 
     getCollectionState(collectionName).forEachReplica((s, replica) -> assertEquals(nodeId, replica.getNodeName()));
 
     CollectionAdminRequest.addReplicaToShard(collectionName, "shard1").process(solrClient);
-    waitForState("Timed out waiting to see 2 replicas for collection: " + collectionName,
+    CloudTestUtils.waitForState(cluster, "Timed out waiting to see 2 replicas for collection: " + collectionName,
         collectionName, (liveNodes, collectionState) -> collectionState.getReplicas().size() == 2);
 
     getCollectionState(collectionName).forEachReplica((s, replica) -> assertEquals(nodeId, replica.getNodeName()));
@@ -148,7 +151,8 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
     CollectionAdminRequest.createCollection(collectionName, "conf", 1, 2)
         .setPolicy("c1")
         .process(solrClient);
-    waitForState("Timeout waiting for collection to become active", collectionName, clusterShape(1, 2));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", collectionName,
+        CloudTestUtils.clusterShape(1, 2));
 
     DocCollection docCollection = getCollectionState(collectionName);
     List<Replica> list = docCollection.getReplicas(firstNode);
@@ -161,7 +165,7 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
 
     CollectionAdminRequest.splitShard(collectionName).setShardName("shard1").process(solrClient);
 
-    waitForState("Timed out waiting to see 6 replicas for collection: " + collectionName,
+    CloudTestUtils.waitForState(cluster, "Timed out waiting to see 6 replicas for collection: " + collectionName,
         collectionName, (liveNodes, collectionState) -> collectionState.getReplicas().size() == 6);
 
     docCollection = getCollectionState(collectionName);
@@ -206,7 +210,8 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
     //org.eclipse.jetty.server.handler.DefaultHandler.2xx-responses
     CollectionAdminRequest.createCollection("metricsTest", "conf", 1, 1)
         .process(solrClient);
-    waitForState("Timeout waiting for collection to become active", "metricsTest", clusterShape(1, 1));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", "metricsTest",
+        CloudTestUtils.clusterShape(1, 1));
 
     DocCollection collection = getCollectionState("metricsTest");
     List<String> tags = Arrays.asList("metrics:solr.node:ADMIN./admin/authorization.clientErrors:count",
@@ -251,7 +256,8 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
 
     CollectionAdminRequest.createCollectionWithImplicitRouter("policiesTest", "conf", "s1", 1, 1, 1)
         .process(solrClient);
-    waitForState("Timeout waiting for collection to become active", "policiesTest", clusterShape(1, 3));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", "policiesTest",
+        CloudTestUtils.clusterShape(1, 3));
 
     DocCollection coll = getCollectionState("policiesTest");
 
@@ -295,14 +301,16 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
     CollectionAdminRequest.createCollectionWithImplicitRouter("policiesTest", "conf", "s1,s2", 1)
         .setPolicy("c1")
         .process(solrClient);
-    waitForState("Timeout waiting for collection to become active", "policiesTest", clusterShape(2, 1));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", "policiesTest",
+        CloudTestUtils.clusterShape(2, 1));
 
     DocCollection coll = getCollectionState("policiesTest");
     assertEquals("c1", coll.getPolicyName());
     assertEquals(2,coll.getReplicas().size());
     coll.forEachReplica((s, replica) -> assertEquals(nodeId, replica.getNodeName()));
     CollectionAdminRequest.createShard("policiesTest", "s3").process(solrClient);
-    waitForState("Timeout waiting for collection to become active", "policiesTest", clusterShape(3, 1));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", "policiesTest",
+        CloudTestUtils.clusterShape(3, 1));
 
     coll = getCollectionState("policiesTest");
     assertEquals(1, coll.getSlice("s3").getReplicas().size());
@@ -313,7 +321,8 @@ public class TestPolicyCloud extends SimSolrCloudTestCase {
     SolrClient solrClient = cluster.simGetSolrClient();
     CollectionAdminRequest.createCollectionWithImplicitRouter("policiesTest", "conf", "shard1", 2)
         .process(solrClient);
-    waitForState("Timeout waiting for collection to become active", "policiesTest", clusterShape(1, 2));
+    CloudTestUtils.waitForState(cluster, "Timeout waiting for collection to become active", "policiesTest",
+        CloudTestUtils.clusterShape(1, 2));
     DocCollection rulesCollection = getCollectionState("policiesTest");
 
     Map<String, Object> val = cluster.getNodeStateProvider().getNodeValues(rulesCollection.getReplicas().get(0).getNodeName(), Arrays.asList(

solr/core/src/test/org/apache/solr/cloud/autoscaling/sim/TestTriggerIntegration.java

@@ -40,6 +40,7 @@ import org.apache.solr.client.solrj.cloud.autoscaling.SolrCloudManager;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventProcessorStage;
 import org.apache.solr.client.solrj.cloud.autoscaling.TriggerEventType;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.CloudTestUtils;
 import org.apache.solr.cloud.autoscaling.ActionContext;
 import org.apache.solr.cloud.autoscaling.ComputePlanAction;
 import org.apache.solr.cloud.autoscaling.ExecutePlanAction;
@@ -109,6 +110,14 @@ public class TestTriggerIntegration extends SimSolrCloudTestCase {
 
   @Before
   public void setupTest() throws Exception {
+    // disable .scheduled_maintenance
+    String suspendTriggerCommand = "{" +
+        "'suspend-trigger' : {'name' : '.scheduled_maintenance'}" +
+        "}";
+    SolrRequest req = createAutoScalingRequest(SolrRequest.METHOD.POST, suspendTriggerCommand);
+    SolrClient solrClient = cluster.simGetSolrClient();
+    NamedList<Object> response = solrClient.request(req);
+    assertEquals(response.get("result").toString(), "success");
 
     waitForSeconds = 1 + random().nextInt(3);
     actionConstructorCalled = new CountDownLatch(1);
@@ -1140,7 +1149,7 @@ public class TestTriggerIntegration extends SimSolrCloudTestCase {
     CollectionAdminRequest.Create create = CollectionAdminRequest.createCollection(COLL1,
         "conf", 1, 2);
     create.process(solrClient);
-    waitForState(COLL1, 10, TimeUnit.SECONDS, clusterShape(1, 2));
+    CloudTestUtils.waitForState(cluster, COLL1, 10, TimeUnit.SECONDS, CloudTestUtils.clusterShape(1, 2));
 
     String setTriggerCommand = "{" +
         "'set-trigger' : {" +

solr/solrj/src/java/org/apache/solr/client/solrj/cloud/autoscaling/AlreadyExistsException.java

@@ -21,15 +21,15 @@ package org.apache.solr.client.solrj.cloud.autoscaling;
  */
 public class AlreadyExistsException extends Exception {
 
-  private final String path;
+  private final String id;
 
-  public AlreadyExistsException(String path) {
+  public AlreadyExistsException(String id) {
-    super("Path already exists: " + path);
+    super("Already exists: " + id);
-    this.path = path;
+    this.id = id;
   }
 
-  public String getPath() {
+  public String getId() {
-    return path;
+    return id;
   }
 
 }

solr/solrj/src/java/org/apache/solr/common/cloud/ZkStateReader.java

@@ -95,6 +95,7 @@ public class ZkStateReader implements Closeable {
   public static final String PROPERTY_VALUE_PROP = "property.value";
   public static final String MAX_AT_ONCE_PROP = "maxAtOnce";
   public static final String MAX_WAIT_SECONDS_PROP = "maxWaitSeconds";
+  public static final String STATE_TIMESTAMP_PROP = "stateTimestamp";
   public static final String COLLECTIONS_ZKNODE = "/collections";
   public static final String LIVE_NODES_ZKNODE = "/live_nodes";
   public static final String ALIASES = "/aliases.json";

solr/solrj/src/java/org/apache/solr/common/params/CollectionParams.java

@@ -118,7 +118,8 @@ public interface CollectionParams {
     //TODO when we have a node level lock use it here
     REPLACENODE(true, LockLevel.NONE),
     DELETENODE(true, LockLevel.NONE),
-    MOCK_REPLICA_TASK(false, LockLevel.REPLICA)
+    MOCK_REPLICA_TASK(false, LockLevel.REPLICA),
+    NONE(false, LockLevel.NONE)
     ;
     public final boolean isWrite;
 

solr/solrj/src/java/org/apache/solr/common/util/TimeSource.java

@@ -25,14 +25,19 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * Source of time. NOTE: depending on implementation returned values may not be related in any way to the
+ * Source of time.
- * current Epoch or calendar time, and they may even be negative - but the API guarantees that they are
+ * <p>NOTE: depending on implementation returned values may not be related in any way to the
- * always monotonically increasing.
+ * current Epoch or calendar time, and they may even be negative - but the API guarantees that
+ * they are always monotonically increasing.</p>
  */
 public abstract class TimeSource {
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
 
-  /** Implementation that uses {@link System#currentTimeMillis()}. */
+  /**
+   * Implementation that uses {@link System#currentTimeMillis()}.
+   * This implementation's {@link #getTime()} returns the same values as
+   * {@link #getEpochTime()}.
+   */
   public static final class CurrentTimeSource extends TimeSource {
 
     @Override
@@ -41,6 +46,11 @@ public abstract class TimeSource {
       return TimeUnit.NANOSECONDS.convert(System.currentTimeMillis(), TimeUnit.MILLISECONDS);
     }
 
+    @Override
+    public long getEpochTime() {
+      return getTime();
+    }
+
     @Override
     public void sleep(long ms) throws InterruptedException {
       Thread.sleep(ms);
@@ -52,14 +62,31 @@ public abstract class TimeSource {
     }
   }
 
-  /** Implementation that uses {@link System#nanoTime()}. */
+  /**
+   * Implementation that uses {@link System#nanoTime()}.
+   * Epoch time is initialized using {@link CurrentTimeSource}, and then
+   * calculated as the elapsed number of nanoseconds as measured by this
+   * implementation.
+   */
   public static final class NanoTimeSource extends TimeSource {
+    private final long epochStart;
+    private final long nanoStart;
+
+    public NanoTimeSource() {
+      epochStart = CURRENT_TIME.getTime();
+      nanoStart = System.nanoTime();
+    }
 
     @Override
     public long getTime() {
       return System.nanoTime();
     }
 
+    @Override
+    public long getEpochTime() {
+      return epochStart + getTime() - nanoStart;
+    }
+
     @Override
     public void sleep(long ms) throws InterruptedException {
       Thread.sleep(ms);
@@ -75,24 +102,27 @@ public abstract class TimeSource {
   public static final class SimTimeSource extends TimeSource {
 
     final double multiplier;
-    long start;
+    final long nanoStart;
+    final long epochStart;
 
     /**
-     * Create a simulated time source that runs faster than real time by a multipler.
+     * Create a simulated time source that runs faster than real time by a multiplier.
      * @param multiplier must be greater than 0.0
      */
     public SimTimeSource(double multiplier) {
       this.multiplier = multiplier;
-      start = NANO_TIME.getTime();
+      epochStart = CURRENT_TIME.getTime();
-    }
+      nanoStart = NANO_TIME.getTime();
-
-    public void advance(long delta) {
-      start = getTime() + delta;
     }
 
     @Override
     public long getTime() {
-      return start + Math.round((double)(NANO_TIME.getTime() - start) * multiplier);
+      return nanoStart + Math.round((double)(NANO_TIME.getTime() - nanoStart) * multiplier);
+    }
+
+    @Override
+    public long getEpochTime() {
+      return epochStart + getTime() - nanoStart;
     }
 
     @Override
@@ -151,10 +181,18 @@ public abstract class TimeSource {
   }
 
   /**
-   * Return a time value, in nanosecond unit.
+   * Return a time value, in nanosecond units. Depending on implementation this value may or
+   * may not be related to Epoch time.
    */
   public abstract long getTime();
 
+  /**
+   * Return Epoch time. Implementations that are not natively based on epoch time may
+   * return values that are consistently off by a (small) fixed number of milliseconds from
+   * the actual epoch time.
+   */
+  public abstract long getEpochTime();
+
   public abstract void sleep(long ms) throws InterruptedException;
 
   public abstract long convertDelay(TimeUnit fromUnit, long value, TimeUnit toUnit);