143 lines
5.4 KiB
Plaintext
143 lines
5.4 KiB
Plaintext
[[cat-shards]]
|
|
== cat shards
|
|
|
|
The `shards` command is the detailed view of what nodes contain which
|
|
shards. It will tell you if it's a primary or replica, the number of
|
|
docs, the bytes it takes on disk, and the node where it's located.
|
|
|
|
Here we see a single index, with one primary shard and no replicas:
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
GET _cat/shards
|
|
---------------------------------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[setup:twitter]
|
|
|
|
This will return
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
twitter 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA
|
|
---------------------------------------------------------------------------
|
|
// TESTRESPONSE[s/3014/\\d+/]
|
|
// TESTRESPONSE[s/31.1mb/\\d+(\.\\d+)?[kmg]?b/]
|
|
// TESTRESPONSE[s/192.168.56.10/.*/]
|
|
// TESTRESPONSE[s/H5dfFeA/node-0/ _cat]
|
|
|
|
[float]
|
|
[[index-pattern]]
|
|
=== Index pattern
|
|
|
|
If you have many shards, you may wish to limit which indices show up
|
|
in the output. You can always do this with `grep`, but you can save
|
|
some bandwidth by supplying an index pattern to the end.
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
GET _cat/shards/twitt*
|
|
---------------------------------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[setup:twitter]
|
|
|
|
Which will return the following
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
twitter 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA
|
|
---------------------------------------------------------------------------
|
|
// TESTRESPONSE[s/3014/\\d+/]
|
|
// TESTRESPONSE[s/31.1mb/\\d+(\.\\d+)?[kmg]?b/]
|
|
// TESTRESPONSE[s/192.168.56.10/.*/]
|
|
// TESTRESPONSE[s/H5dfFeA/node-0/ _cat]
|
|
|
|
|
|
[float]
|
|
[[relocation]]
|
|
=== Relocation
|
|
|
|
Let's say you've checked your health and you see a relocating
|
|
shards. Where are they from and where are they going?
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
GET _cat/shards
|
|
---------------------------------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[skip:for now, relocation cannot be recreated]
|
|
|
|
A relocating shard will be shown as follows
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
twitter 0 p RELOCATING 3014 31.1mb 192.168.56.10 H5dfFeA -> -> 192.168.56.30 bGG90GE
|
|
---------------------------------------------------------------------------
|
|
// TESTRESPONSE[_cat]
|
|
|
|
[float]
|
|
[[states]]
|
|
=== Shard states
|
|
|
|
Before a shard can be used, it goes through an `INITIALIZING` state.
|
|
`shards` can show you which ones.
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
GET _cat/shards
|
|
---------------------------------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[skip:there is no guarantee to test for shards in initializing state]
|
|
|
|
You can the the initializing state in the response like this
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
twitter 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA
|
|
twitter 0 r INITIALIZING 0 14.3mb 192.168.56.30 bGG90GE
|
|
---------------------------------------------------------------------------
|
|
// TESTRESPONSE[_cat]
|
|
|
|
If a shard cannot be assigned, for example you've overallocated the
|
|
number of replicas for the number of nodes in the cluster, the shard
|
|
will remain `UNASSIGNED` with the <<reason-unassigned,reason code>> `ALLOCATION_FAILED`.
|
|
|
|
You can use the shards API to find out that reason.
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
GET _cat/shards?h=index,shard,prirep,state,unassigned.reason
|
|
---------------------------------------------------------------------------
|
|
// CONSOLE
|
|
// TEST[skip:for now]
|
|
|
|
The reason for an unassigned shard will be listed as the last field
|
|
|
|
[source,js]
|
|
---------------------------------------------------------------------------
|
|
twitter 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA
|
|
twitter 0 r STARTED 3014 31.1mb 192.168.56.30 bGG90GE
|
|
twitter 0 r STARTED 3014 31.1mb 192.168.56.20 I8hydUG
|
|
twitter 0 r UNASSIGNED ALLOCATION_FAILED
|
|
---------------------------------------------------------------------------
|
|
// TESTRESPONSE[_cat]
|
|
|
|
[float]
|
|
[[reason-unassigned]]
|
|
=== Reasons for unassigned shard
|
|
|
|
These are the possible reasons for a shard to be in a unassigned state:
|
|
|
|
[horizontal]
|
|
`INDEX_CREATED`:: Unassigned as a result of an API creation of an index.
|
|
`CLUSTER_RECOVERED`:: Unassigned as a result of a full cluster recovery.
|
|
`INDEX_REOPENED`:: Unassigned as a result of opening a closed index.
|
|
`DANGLING_INDEX_IMPORTED`:: Unassigned as a result of importing a dangling index.
|
|
`NEW_INDEX_RESTORED`:: Unassigned as a result of restoring into a new index.
|
|
`EXISTING_INDEX_RESTORED`:: Unassigned as a result of restoring into a closed index.
|
|
`REPLICA_ADDED`:: Unassigned as a result of explicit addition of a replica.
|
|
`ALLOCATION_FAILED`:: Unassigned as a result of a failed allocation of the shard.
|
|
`NODE_LEFT`:: Unassigned as a result of the node hosting it leaving the cluster.
|
|
`REROUTE_CANCELLED`:: Unassigned as a result of explicit cancel reroute command.
|
|
`REINITIALIZED`:: When a shard moves from started back to initializing, for example, with shadow replicas.
|
|
`REALLOCATED_REPLICA`:: A better replica location is identified and causes the existing replica allocation to be cancelled.
|