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HADOOP-18365. Update the remote address when a change is detected (#4692) 

Avoid reconnecting to the old address after detecting that the address has been updated.

* Fix Checkstyle line length violation
* Keep ConnectionId as Immutable for map key

The ConnectionId is used as a key in the connections map, and updating the remoteId caused problems with the cleanup of connections when the removeMethod was used.

Instead of updating the address within the remoteId, use the removeMethod to cleanup references to the current identifier and then replace it with a new identifier using the updated address.

* Use final to protect immutable ConnectionId

Mark non-test fields as private and final, and add a missing accessor.

* Use a stable hashCode to allow safe IP addr changes
* Add test that updated address is used

Once the address has been updated, it should be used in future calls.  Check to ensure that a second request succeeds and that it uses the existing updated address instead of having to re-resolve.

Signed-off-by: Nick Dimiduk <ndimiduk@apache.org>
Signed-off-by: sokui
Signed-off-by: XanderZu
Signed-off-by: stack <stack@apache.org>
This commit is contained in:
Steve Vaughan 2022-08-18 12:21:23 -04:00 committed by GitHub
parent d09dd4a0b9
commit b7d4dc61bf
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 113 additions and 8 deletions
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36
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Client.java
View File

@ -645,6 +645,9 @@ public class Client implements AutoCloseable {
LOG.warn("Address change detected. Old: " + server.toString() +
" New: " + currentAddr.toString());
server = currentAddr;
// Update the remote address so that reconnections are with the updated address.
// This avoids thrashing.
remoteId.setAddress(currentAddr);
UserGroupInformation ticket = remoteId.getTicket();
this.setName("IPC Client (" + socketFactory.hashCode()
+ ") connection to " + server.toString() + " from "
@ -1700,9 +1703,9 @@ public class Client implements AutoCloseable {
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public static class ConnectionId {
InetSocketAddress address;
UserGroupInformation ticket;
final Class<?> protocol;
private InetSocketAddress address;
private final UserGroupInformation ticket;
private final Class<?> protocol;
private static final int PRIME = 16777619;
private final int rpcTimeout;
private final int maxIdleTime; //connections will be culled if it was idle for
@ -1754,6 +1757,27 @@ public class Client implements AutoCloseable {
return address;
}
/**
* This is used to update the remote address when an address change is detected. This method
* ensures that the {@link #hashCode()} won't change.
*
* @param address the updated address
* @throws IllegalArgumentException if the hostname or port doesn't match
* @see Connection#updateAddress()
*/
void setAddress(InetSocketAddress address) {
if (!Objects.equals(this.address.getHostName(), address.getHostName())) {
throw new IllegalArgumentException("Hostname must match: " + this.address + " vs "
+ address);
}
if (this.address.getPort() != address.getPort()) {
throw new IllegalArgumentException("Port must match: " + this.address + " vs " + address);
}
this.address = address;
}
Class<?> getProtocol() {
return protocol;
}
@ -1864,7 +1888,11 @@ public class Client implements AutoCloseable {
@Override
public int hashCode() {
int result = connectionRetryPolicy.hashCode();
result = PRIME * result + ((address == null) ? 0 : address.hashCode());
// We calculate based on the host name and port without the IP address, since the hashCode
// must be stable even if the IP address is updated.
result = PRIME * result + ((address == null || address.getHostName() == null) ? 0 :
address.getHostName().hashCode());
result = PRIME * result + ((address == null) ? 0 : address.getPort());
result = PRIME * result + (doPing ? 1231 : 1237);
result = PRIME * result + maxIdleTime;
result = PRIME * result + pingInterval;

2
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/WritableRpcEngine.java
View File

@ -323,7 +323,7 @@ public class WritableRpcEngine implements RpcEngine {
Client.ConnectionId connId, Configuration conf, SocketFactory factory)
throws IOException {
return getProxy(protocol, clientVersion, connId.getAddress(),
connId.ticket, conf, factory, connId.getRpcTimeout(),
connId.getTicket(), conf, factory, connId.getRpcTimeout(),
connId.getRetryPolicy(), null, null);
}

77
hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/ipc/TestIPC.java
View File

@ -18,6 +18,7 @@
package org.apache.hadoop.ipc;
import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
@ -93,6 +94,7 @@ import org.apache.hadoop.test.GenericTestUtils;
import org.apache.hadoop.test.LambdaTestUtils;
import org.apache.hadoop.test.Whitebox;
import org.apache.hadoop.util.StringUtils;
import org.assertj.core.api.Condition;
import org.junit.Assert;
import org.junit.Assume;
import org.junit.Before;
@ -815,6 +817,81 @@ public class TestIPC {
}
}
/**
* The {@link ConnectionId#hashCode} has to be stable despite updates that occur as the the
* address evolves over time. The {@link ConnectionId} is used as a primary key in maps, so
* its hashCode can't change.
*
* @throws IOException if there is a client or server failure
*/
@Test
public void testStableHashCode() throws IOException {
Server server = new TestServer(5, false);
try {
server.start();
// Leave host unresolved to start. Use "localhost" as opposed
// to local IP from NetUtils.getConnectAddress(server) to force
// resolution later
InetSocketAddress unresolvedAddr = InetSocketAddress.createUnresolved(
"localhost", NetUtils.getConnectAddress(server).getPort());
// Setup: Create a ConnectionID using an unresolved address, and get it's hashCode to serve
// as a point of comparison.
int rpcTimeout = MIN_SLEEP_TIME * 2;
final ConnectionId remoteId = getConnectionId(unresolvedAddr, rpcTimeout, conf);
int expected = remoteId.hashCode();
// Start client
Client.setConnectTimeout(conf, 100);
Client client = new Client(LongWritable.class, conf);
try {
// Test: Call should re-resolve host and succeed
LongWritable param = new LongWritable(RANDOM.nextLong());
client.call(RPC.RpcKind.RPC_BUILTIN, param, remoteId,
RPC.RPC_SERVICE_CLASS_DEFAULT, null);
int actual = remoteId.hashCode();
// Verify: The hashCode should match, although the InetAddress is different since it has
// now been resolved
assertThat(remoteId.getAddress()).isNotEqualTo(unresolvedAddr);
assertThat(remoteId.getAddress().getHostName()).isEqualTo(unresolvedAddr.getHostName());
assertThat(remoteId.hashCode()).isEqualTo(expected);
// Test: Call should succeed without having to re-resolve
InetSocketAddress expectedSocketAddress = remoteId.getAddress();
param = new LongWritable(RANDOM.nextLong());
client.call(RPC.RpcKind.RPC_BUILTIN, param, remoteId,
RPC.RPC_SERVICE_CLASS_DEFAULT, null);
// Verify: The same instance of the InetSocketAddress has been used to make the second
// call
assertThat(remoteId.getAddress()).isSameAs(expectedSocketAddress);
// Verify: The hashCode is protected against updates to the host name
String hostName = InetAddress.getLocalHost().getHostName();
InetSocketAddress mismatchedHostName = NetUtils.createSocketAddr(
InetAddress.getLocalHost().getHostName(),
remoteId.getAddress().getPort());
assertThatExceptionOfType(IllegalArgumentException.class)
.isThrownBy(() -> remoteId.setAddress(mismatchedHostName))
.withMessageStartingWith("Hostname must match");
// Verify: The hashCode is protected against updates to the port
InetSocketAddress mismatchedPort = NetUtils.createSocketAddr(
remoteId.getAddress().getHostName(),
remoteId.getAddress().getPort() + 1);
assertThatExceptionOfType(IllegalArgumentException.class)
.isThrownBy(() -> remoteId.setAddress(mismatchedPort))
.withMessageStartingWith("Port must match");
} finally {
client.stop();
}
} finally {
server.stop();
}
}
@Test(timeout=60000)
public void testIpcFlakyHostResolution() throws IOException {
// start server