Briefly, this error occurs when Elasticsearch is unable to reschedule the persistent tasks rechecker due to issues like cluster state changes, node failures, or network disruptions. To resolve this, you can try restarting the Elasticsearch node, checking the cluster health and ensuring it’s green, or verifying network connectivity between nodes. If the issue persists, you may need to investigate the Elasticsearch logs for more detailed error information.
This guide will help you check for common problems that cause the log ” failed to reschedule persistent tasks rechecker ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: persistent.
Overview
In Elasticsearch, persistent refers to cluster settings that persist across cluster restarts. This setting is used in Cluster Update API calls. Persistent settings can also be configured in the elasticsearch.yml file.
Examples
## enable shard routing
PUT /_cluster/settings
{
"persistent" : {
"cluster.routing.allocation.enable" : "all"
}
}
## enable rebalancing of shards
PUT /_cluster/settings
{
"persistent" : {
"cluster.routing.rebalance.enable" : "all"
}
}
## limit the heap size for fielddata
PUT /_cluster/settings
{
"persistent" : {
“indices.breaker.fielddata.limit”: "30%"
}
}Log Context
Log “failed to reschedule persistent tasks rechecker” classname is PersistentTasksClusterService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
// but only do this if the node is still the master
try {
periodicRechecker.rescheduleIfNecessary();
} catch (Exception e2) {
assert e2 instanceof EsRejectedExecutionException esre && esre.isExecutorShutdown() : e2;
logger.warn("failed to reschedule persistent tasks rechecker"; e2);
}
}
}
@Override
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