How To Solve Issues Related to Log – Recover_after_time elapsed. performing state recovery

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Updated: Feb-20

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Troubleshooting background

To troubleshoot Elasticsearch log “Recover_after_time elapsed. performing state recovery” it’s important to understand common problems related to Elasticsearch concepts: plugin. See detailed explanations below complete with common problems, examples and useful tips.

Plugin in Elasticsearch

What it is

A plugin is used to enhance the core functionalities of Elasticsearch. Elasticsearch provides some core plugins as a part of their release installation. In addition to those core plugins, it is possible to write your own custom plugins as well. There are several community plugins available on GitHub for various use cases.

Examples:
  • Get all the instructions for the plugin usage
sudo bin/elasticsearch-plugin -h
  • Installing S3 plugin using URL for storing Elasticsearch snapshots on S3
sudo bin/elasticsearch-plugin install repository-s3
  • Removing a plugin
sudo bin/elasticsearch-plugin remove repository-s3
  • Installing a plugin using the file path
sudo bin/elasticsearch-plugin install file:///path/to/plugin.zip

Notes:
  • Plugins are installed and removed using the elasticsearch-plugin script, which ships as a part of Elasticsearch installation and can be found inside the bin/ directory of the Elasticsearch installation path.
  • A plugin has to be installed on every node of the cluster and each of the nodes has to be restarted to make the plugin visible.
  • You can also download the plugin manually and then install it using the elasticsearch-plugin install command, providing the file name/path of the plugin’s source file.
  • When a plugin is removed, you will need to restart every elasticsearch node in order to complete the removal process.

Common Problems:
  • Managing permission issues during and after plugin installation is the most common problem. If Elasticsearch was installed using the deb or rpm package then the plugin has to be installed using the root user, or else you can install the plugin as the user that owns all of the Elasticsearch files.
  • In case of deb or rpm package installation, it is important to check the permission of the plugins directory after plugin installation and update the permission if it has been modified using the following command:
chown -R elasticsearch:elasticsearch path_to_plugin_directory 
  • If your Elasticsearch nodes are running in a private subnet without internet access, you cannot install a plugin directly. In this case, you can simply download the plugins at once and copy the files inside the plugins directory of the Elasticsearch installation path on every node. The node has to be restarted in this case as well.

Recovery in Elasticsearch

What it is

In Elasticsearch, recovery refers to the process of recovering an index/shard when something goes wrong. You can recover an index/shards in many ways such as by re-indexing the data from a  backup/failover cluster to the current one or by restoring from an Elasticsearch snapshot. Alternatively, Elasticsearch may be performing recoveries automatically in some cases, such as when a node restarts or when a node disconnects and connects again. There is an API to check the updated status of index/shard recoveries.

GET /<index>/_recoveryGET /_recovery

In summary, recovery can happen in the following situations:

  • Node startup or failure ( local store recovery )
  • Replication of Primary shards to replica shards
  • Relocation of a shard to a different node in the same cluster
  • Restoring a Snapshot
Examples:

Getting recovery information about several indices:

GET my_index1,my_index2/_recovery
Common Problems Related to Recovery Settings
  • When a node is disconnected from the cluster, all of its shards go to an unassigned state. After a certain time, the shards will be allocated somewhere else on other nodes. This setting determines the number of concurrent shards per node that will be recovered.
PUT _cluster/settings{  "transient" :  {     "cluster.routing.allocation.node_concurrent_recoveries" : 3 }}
  • You can also control when to start recovery after a node disconnects. ( This is useful if the node just restarts, for example, because you may not want to initiate any recovery for such transient events )
PUT _all/_settings{  "settings": {    "index.unassigned.node_left.delayed_timeout": "6m"  }}
  • Elasticsearch limits the speed that is allocated to recovery in order to avoid overloading the cluster. This setting can be updated to make the recovery faster or slower, depending on your requirements.
PUT _cluster/settings{  "transient" :  {     "indices.recovery.max_bytes_per_sec" : "100mb"}}

To help troubleshoot related issues we have gathered selected Q&A from the community and issues from Github , please review the following for further information :

1 ElasticSearch: Unassigned Shards, how to fix? 210.06 K 159

2 ElasticSearch: Unassigned Shards, how to fix? 210.06 K  159


Log Context

Log ”recover_after_time [{}] elapsed. performing state recovery…” classname is GatewayService.java
We have extracted the following from Elasticsearch source code to get an in-depth context :

                 logger.info("delaying initial state recovery for [{}]. {}"; recoverAfterTime; reason);
                threadPool.schedule(recoverAfterTime; ThreadPool.Names.GENERIC; new Runnable() {
                    
Override
                    public void run() {
                        if (recovered.compareAndSet(false; true)) {
                            logger.info("recover_after_time [{}] elapsed. performing state recovery..."; recoverAfterTime);
                            gateway.performStateRecovery(recoveryListener);
                        }
                    }
                });
            }





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