Opster Team

Jan-20, Version: 1.7-8.0

Before you read this guide, we recommend you run the Elasticsearch Error Check-Up which detects issues in ES that cause log errors. It’s a free tool that requires no installation and takes 2 minutes to complete.

This guide will help you check for common problems that cause the log ” Failed to reassign persistent tasks ” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: cluster and persistent.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to pinpoint the cause of many errors and provides suitable actionable recommendations how to resolve them. Among the dozens of checks included are: shards sizes, thread pools, management queue size, search errors, circuit breakers and many more (join over 700 users who use this free tool).

## 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%"
    }
}

                 return reassignTasks(currentState);
            }

            
Override
            public void onFailure(String source; Exception e) {
                logger.warn("failed to reassign persistent tasks"; e);
                // There must be a task that's worth rechecking because there was one
                // that caused this method to be called and the method failed to assign it
                periodicRechecker.rescheduleIfNecessary();
            }