- Elasticsearch Guide: other versions:
- Getting Started
- Setup Elasticsearch
- Breaking changes
- Breaking changes in 5.1
- Breaking changes in 5.0
- Search and Query DSL changes
- Mapping changes
- Percolator changes
- Suggester changes
- Index APIs changes
- Document API changes
- Settings changes
- Allocation changes
- HTTP changes
- REST API changes
- CAT API changes
- Java API changes
- Packaging
- Plugin changes
- Filesystem related changes
- Path to data on disk
- Aggregation changes
- Script related changes
- API Conventions
- Document APIs
- Search APIs
- Aggregations
- Metrics Aggregations
- Avg Aggregation
- Cardinality Aggregation
- Extended Stats Aggregation
- Geo Bounds Aggregation
- Geo Centroid Aggregation
- Max Aggregation
- Min Aggregation
- Percentiles Aggregation
- Percentile Ranks Aggregation
- Scripted Metric Aggregation
- Stats Aggregation
- Sum Aggregation
- Top hits Aggregation
- Value Count Aggregation
- Bucket Aggregations
- Children Aggregation
- Date Histogram Aggregation
- Date Range Aggregation
- Diversified Sampler Aggregation
- Filter Aggregation
- Filters Aggregation
- Geo Distance Aggregation
- GeoHash grid Aggregation
- Global Aggregation
- Histogram Aggregation
- IP Range Aggregation
- Missing Aggregation
- Nested Aggregation
- Range Aggregation
- Reverse nested Aggregation
- Sampler Aggregation
- Significant Terms Aggregation
- Terms Aggregation
- Pipeline Aggregations
- Avg Bucket Aggregation
- Derivative Aggregation
- Max Bucket Aggregation
- Min Bucket Aggregation
- Sum Bucket Aggregation
- Stats Bucket Aggregation
- Extended Stats Bucket Aggregation
- Percentiles Bucket Aggregation
- Moving Average Aggregation
- Cumulative Sum Aggregation
- Bucket Script Aggregation
- Bucket Selector Aggregation
- Serial Differencing Aggregation
- Matrix Aggregations
- Caching heavy aggregations
- Returning only aggregation results
- Aggregation Metadata
- Metrics Aggregations
- Indices APIs
- Create Index
- Delete Index
- Get Index
- Indices Exists
- Open / Close Index API
- Shrink Index
- Rollover Index
- Put Mapping
- Get Mapping
- Get Field Mapping
- Types Exists
- Index Aliases
- Update Indices Settings
- Get Settings
- Analyze
- Index Templates
- Shadow replica indices
- Indices Stats
- Indices Segments
- Indices Recovery
- Indices Shard Stores
- Clear Cache
- Flush
- Refresh
- Force Merge
- cat APIs
- Cluster APIs
- Query DSL
- Mapping
- Analysis
- Anatomy of an analyzer
- Testing analyzers
- Analyzers
- Tokenizers
- Token Filters
- Standard Token Filter
- ASCII Folding Token Filter
- Length Token Filter
- Lowercase Token Filter
- Uppercase Token Filter
- NGram Token Filter
- Edge NGram Token Filter
- Porter Stem Token Filter
- Shingle Token Filter
- Stop Token Filter
- Word Delimiter Token Filter
- Stemmer Token Filter
- Stemmer Override Token Filter
- Keyword Marker Token Filter
- Keyword Repeat Token Filter
- KStem Token Filter
- Snowball Token Filter
- Phonetic Token Filter
- Synonym Token Filter
- Compound Word Token Filter
- Reverse Token Filter
- Elision Token Filter
- Truncate Token Filter
- Unique Token Filter
- Pattern Capture Token Filter
- Pattern Replace Token Filter
- Trim Token Filter
- Limit Token Count Token Filter
- Hunspell Token Filter
- Common Grams Token Filter
- Normalization Token Filter
- CJK Width Token Filter
- CJK Bigram Token Filter
- Delimited Payload Token Filter
- Keep Words Token Filter
- Keep Types Token Filter
- Classic Token Filter
- Apostrophe Token Filter
- Decimal Digit Token Filter
- Fingerprint Token Filter
- Minhash Token Filter
- Character Filters
- Modules
- Index Modules
- Ingest Node
- Pipeline Definition
- Ingest APIs
- Accessing Data in Pipelines
- Handling Failures in Pipelines
- Processors
- Append Processor
- Convert Processor
- Date Processor
- Date Index Name Processor
- Fail Processor
- Foreach Processor
- Grok Processor
- Gsub Processor
- Join Processor
- JSON Processor
- Lowercase Processor
- Remove Processor
- Rename Processor
- Script Processor
- Set Processor
- Split Processor
- Sort Processor
- Trim Processor
- Uppercase Processor
- Dot Expander Processor
- How To
- Testing
- Glossary of terms
- Release Notes
- 5.1.2 Release Notes
- 5.1.1 Release Notes
- 5.1.0 Release Notes
- 5.0.2 Release Notes
- 5.0.1 Release Notes
- 5.0.0 Combined Release Notes
- 5.0.0 GA Release Notes
- 5.0.0-rc1 Release Notes
- 5.0.0-beta1 Release Notes
- 5.0.0-alpha5 Release Notes
- 5.0.0-alpha4 Release Notes
- 5.0.0-alpha3 Release Notes
- 5.0.0-alpha2 Release Notes
- 5.0.0-alpha1 Release Notes
- 5.0.0-alpha1 Release Notes (Changes previously released in 2.x)
WARNING: Version 5.1 of Elasticsearch has passed its EOL date.
This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.
Cluster Reroute
editCluster Reroute
editThe reroute command allows to explicitly execute a cluster reroute allocation command including specific commands. For example, a shard can be moved from one node to another explicitly, an allocation can be canceled, or an unassigned shard can be explicitly allocated on a specific node.
Here is a short example of how a simple reroute API call:
curl -XPOST 'localhost:9200/_cluster/reroute' -d '{ "commands" : [ { "move" : { "index" : "test", "shard" : 0, "from_node" : "node1", "to_node" : "node2" } }, { "allocate_replica" : { "index" : "test", "shard" : 1, "node" : "node3" } } ] }'
An important aspect to remember is the fact that once when an allocation
occurs, the cluster will aim at re-balancing its state back to an even
state. For example, if the allocation includes moving a shard from
node1
to node2
, in an even
state, then another shard will be moved
from node2
to node1
to even things out.
The cluster can be set to disable allocations, which means that only the explicitly allocations will be performed. Obviously, only once all commands has been applied, the cluster will aim to be re-balance its state.
Another option is to run the commands in dry_run
(as a URI flag, or in
the request body). This will cause the commands to apply to the current
cluster state, and return the resulting cluster after the commands (and
re-balancing) has been applied.
If the explain
parameter is specified, a detailed explanation of why the
commands could or could not be executed is returned.
The commands supported are:
-
move
-
Move a started shard from one node to another node. Accepts
index
andshard
for index name and shard number,from_node
for the node to move the shardfrom
, andto_node
for the node to move the shard to. -
cancel
-
Cancel allocation of a shard (or recovery). Accepts
index
andshard
for index name and shard number, andnode
for the node to cancel the shard allocation on. It also acceptsallow_primary
flag to explicitly specify that it is allowed to cancel allocation for a primary shard. This can be used to force resynchronization of existing replicas from the primary shard by cancelling them and allowing them to be reinitialized through the standard reallocation process. -
allocate_replica
-
Allocate an unassigned replica shard to a node. Accepts the
index
andshard
for index name and shard number, andnode
to allocate the shard to. Takes allocation deciders into account.
Two more commands are available that allow the allocation of a primary shard to a node. These commands should however be used with extreme care, as primary shard allocation is usually fully automatically handled by Elasticsearch. Reasons why a primary shard cannot be automatically allocated include the following:
- A new index was created but there is no node which satisfies the allocation deciders.
- An up-to-date shard copy of the data cannot be found on the current data nodes in the cluster. To prevent data loss, the system does not automatically promote a stale shard copy to primary.
As a manual override, two commands to forcefully allocate primary shards are available:
-
allocate_stale_primary
-
Allocate a primary shard to a node that holds a stale copy. Accepts the
index
andshard
for index name and shard number, andnode
to allocate the shard to. Using this command may lead to data loss for the provided shard id. If a node which has the good copy of the data rejoins the cluster later on, that data will be overwritten with the data of the stale copy that was forcefully allocated with this command. To ensure that these implications are well-understood, this command requires the special fieldaccept_data_loss
to be explicitly set totrue
for it to work. -
allocate_empty_primary
-
Allocate an empty primary shard to a node. Accepts the
index
andshard
for index name and shard number, andnode
to allocate the shard to. Using this command leads to a complete loss of all data that was indexed into this shard, if it was previously started. If a node which has a copy of the data rejoins the cluster later on, that data will be deleted! To ensure that these implications are well-understood, this command requires the special fieldaccept_data_loss
to be explicitly set totrue
for it to work.
Retry failed shards
editThe cluster will attempt to allocate a shard a maximum of
index.allocation.max_retries
times in a row (defaults to 5
), before giving
up and leaving the shard unallocated. This scenario can be caused by
structural problems such as having an analyzer which refers to a stopwords
file which doesn’t exist on all nodes.
Once the problem has been corrected, allocation can be manually retried by
calling the _reroute
API with ?retry_failed
, which
will attempt a single retry round for these shards.
On this page