147 lines
4.4 KiB
Markdown
147 lines
4.4 KiB
Markdown
---
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layout: default
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title: Cluster allocation explain
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parent: REST API reference
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nav_order: 10
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---
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# Cluster allocation explain
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Introduced 1.0
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{: .label .label-purple }
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The most basic cluster allocation explain request finds an unassigned shard and explains why it can't be allocated to a node.
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If you add some options, you can instead get information on a specific shard, including why OpenSearch assigned it to its current node.
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## Example
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```json
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GET _cluster/allocation/explain?include_yes_decisions=true
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{
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"index": "movies",
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"shard": 0,
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"primary": true
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}
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```
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## Path and HTTP methods
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```
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GET _cluster/allocation/explain
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POST _cluster/allocation/explain
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```
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## URL parameters
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All cluster allocation explain parameters are optional.
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Parameter | Type | Description
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:--- | :--- | :---
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include_yes_decisions | Boolean | OpenSearch makes a series of yes or no decisions when trying to allocate a shard to a node. If this parameter is true, OpenSearch includes the (generally more numerous) "yes" decisions in its response. Default is false.
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include_disk_info | Boolean | Whether to include information about disk usage in the response. Default is false.
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## Request body
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All cluster allocation explain fields are optional.
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Field | Type | Description
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:--- | :--- | :---
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current_node | String | If you only want an explanation if the shard happens to be on a particular node, specify that node name here.
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index | String | The name of the shard's index.
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primary | Boolean | Whether to provide an explanation for the primary shard (true) or its first replica (false), which share the same shard ID.
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shard | Integer | The shard ID that you want an explanation for.
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## Response
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```json
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{
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"index": "movies",
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"shard": 0,
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"primary": true,
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"current_state": "started",
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"current_node": {
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"id": "d8jRZcW1QmCBeVFlgOJx5A",
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"name": "opensearch-node1",
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"transport_address": "172.24.0.4:9300",
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"weight_ranking": 1
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},
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"can_remain_on_current_node": "yes",
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"can_rebalance_cluster": "yes",
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"can_rebalance_to_other_node": "no",
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"rebalance_explanation": "cannot rebalance as no target node exists that can both allocate this shard and improve the cluster balance",
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"node_allocation_decisions": [{
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"node_id": "vRxi4uPcRt2BtHlFoyCyTQ",
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"node_name": "opensearch-node2",
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"transport_address": "172.24.0.3:9300",
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"node_decision": "no",
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"weight_ranking": 1,
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"deciders": [{
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"decider": "max_retry",
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"decision": "YES",
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"explanation": "shard has no previous failures"
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},
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{
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"decider": "replica_after_primary_active",
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"decision": "YES",
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"explanation": "shard is primary and can be allocated"
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},
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{
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"decider": "enable",
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"decision": "YES",
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"explanation": "all allocations are allowed"
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},
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{
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"decider": "node_version",
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"decision": "YES",
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"explanation": "can relocate primary shard from a node with version [1.0.0] to a node with equal-or-newer version [1.0.0]"
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},
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{
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"decider": "snapshot_in_progress",
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"decision": "YES",
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"explanation": "no snapshots are currently running"
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},
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{
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"decider": "restore_in_progress",
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"decision": "YES",
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"explanation": "ignored as shard is not being recovered from a snapshot"
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},
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{
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"decider": "filter",
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"decision": "YES",
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"explanation": "node passes include/exclude/require filters"
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},
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{
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"decider": "same_shard",
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"decision": "NO",
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"explanation": "a copy of this shard is already allocated to this node [[movies][0], node[vRxi4uPcRt2BtHlFoyCyTQ], [R], s[STARTED], a[id=x8w7QxWdQQa188HKGn0iMQ]]"
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},
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{
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"decider": "disk_threshold",
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"decision": "YES",
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"explanation": "enough disk for shard on node, free: [35.9gb], shard size: [15.1kb], free after allocating shard: [35.9gb]"
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},
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{
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"decider": "throttling",
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"decision": "YES",
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"explanation": "below shard recovery limit of outgoing: [0 < 2] incoming: [0 < 2]"
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},
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{
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"decider": "shards_limit",
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"decision": "YES",
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"explanation": "total shard limits are disabled: [index: -1, cluster: -1] <= 0"
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},
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{
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"decider": "awareness",
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"decision": "YES",
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"explanation": "allocation awareness is not enabled, set cluster setting [cluster.routing.allocation.awareness.attributes] to enable it"
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}
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]
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}]
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}
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```
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