How To Solve Issues Related to Log – Persistent task with id and allocation id failed to create

Get an Elasticsearch Check-Up

Check if your ES issues are caused from misconfigured settings
(Free 2 min process)

Check-Up

Last update: Jan-20

Elasticsearch Error Guide In Page Navigation (click to jump) :

Troubleshooting Background – start here to get the full picture       
Related Issues – selected resources on related issues  
Log Context – usefull for experts
About Opster – offering a diffrent approach to troubleshoot Elasticsearch

Check Your Elasticsearch Settings for Painfull Mistakes 


Troubleshooting background

To troubleshoot Elasticsearch log “Persistent task with id and allocation id failed to create” it’s important to know common problems related to Elasticsearch concepts: allocation, node, persistent, task. See below-detailed explanations complete with common problems, examples and useful tips.

Nodes in Elasticsearch

What it is

Simply explained a node is a single server that is part of a cluster. Each node is assigned with one or more roles, which describes the node responsibility and operations – Data nodes stores the data, and participates in the cluster’s indexing and search capabilities, while master nodes are responsible for managing the cluster activities and storing the cluster state, including the metadata.

While it’s possible to run several Node instances of Elasticsearch on the same hardware, it’s considered a best practice to limit a server to a single running instance of Elasticsearch.

Nodes connect to each other and form a cluster by using a discovery method. 

Roles
Master node

Master nodes are in charge of cluster-wide settings and changes  – deleting or creating indices and fields, adding or removing nodes and allocating shards to nodes. Each cluster has a single master node that is elected from the master eligible nodes using a distributed consensus algorithm and is reelected if the current master node fails.

Coordinator Node (aka client node)

Coordinator Node – is a node that does not hold any configured role. It doesn’t hold data, not part of the master eligible group nor execute ingest pipelines. Coordinator node serves incoming search requests and is acting as the query coordinator – running the query and fetch phases, sending requests to every node which holds a shard being queried. The client node also distributes bulk indexing operations and route queries to shards copies based on the nodes responsiveness.

Persistent in Elasticsearch

What it is

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 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%"
    }
}


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. Github Issue Number 44566  

2. Github Issue Number 37545      


Log Context

Log ”Persistent task with id and allocation id failed to create” classname is PersistentTasksNodeService.java
We have extracted the following from Elasticsearch source code to get an in-depth context :

             }
            processed = true;
        } finally {
            if (processed == false) {
                // something went wrong - unregistering task
                logger.warn("Persistent task [{}] with id [{}] and allocation id [{}] failed to create"; task.getAction();
                        task.getPersistentTaskId(); task.getAllocationId());
                taskManager.unregister(task);
            }
        }
    }






About Opster

Incorporating deep knowledge and broad history of Elasticsearch issues. Opster’s solution identifies and predicts root causes of Elasticsearch problems, provides recommendations and can automatically perform various actions to manage, troubleshoot and prevent issues

Learn more: Glossary | Blog| Troubleshooting guides | Error Repository

Need help with any Elasticsearch issue ? Contact Opster

Did this page help you?