How To Solve Issues Related to Log – Failed to send join request to master ; reason ; tried times

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Updated: Jan-20

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Troubleshooting background

To troubleshoot Elasticsearch log “Failed to send join request to master ; reason ; tried times” it’s important to understand common problems related to Elasticsearch concepts: discovery, index, join, master, request, . See detailed explanations below complete with common problems, examples and useful tips.

Index in Elasticsearch

What it is

In Elasticsearch, an index (indices in plural) can be thought of as a table inside a database that has a schema and can have one or more shards and replicas. An Elasticsearch index is divided into shards and each shard is an instance of a Lucene index.

Indices are used to store the documents in dedicated data structures corresponding to the data type of fields. For example, text fields are stored inside an inverted index whereas numeric and geo fields are stored inside BKD trees.

Examples
Create Index

The following example is based on Elasticsearch version 5.x onwards. An index with two shards, each having one replica will be created with the name test_index1

PUT /test_index1?pretty
{
    "settings" : {
        "number_of_shards" : 2,
        "number_of_replicas" : 1
    },
    "mappings" : {
        "properties" : {
            "tags" : { "type" : "keyword" },
            "updated_at" : { "type" : "date" }
        }
    }
}
List Indices

All the index names and their basic information can be retrieved using the following command:

GET _cat/indices?v
Index a document

Let’s add a document in the index with below command:

PUT test_index1/_doc/1
{
  "tags": [
    "opster",
    "elasticsearch"
  ],
  "date": "01-01-2020"
}
Query an index
GET test_index1/_search
{
  "query": {
    "match_all": {}
  }
}
Query Multiple Indices

It is possible to search multiple indices with a single request. If it is a raw HTTP request, Index names should be sent in comma-separated format, as shown in the example below, and in the case of a query via a programming language client such as python or Java, index names are to be sent in a list format.

GET test_index1,test_index2/_search
Delete Indices
DELETE test_index1
Common Problems
  • It is good practice to define the settings and mapping of an Index wherever possible because if this is not done, Elasticsearch tries to automatically guess the data type of fields at the time of indexing. This automatic process may have disadvantages, such as mapping conflicts, duplicate data and incorrect data types being set in the index. If the fields are not known in advance, it’s better to use dynamic index templates.
  • Elasticsearch supports wildcard patterns in Index names, which sometimes aids with querying multiple indices, but can also be very destructive too. For example, It is possible to delete all the indices in a single command using the following commands:
DELETE /*

To disable this, you can add the following lines in the elasticsearch.yml:

action.destructive_requires_name: true

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Discovery in Elasticsearch


What it is

The process known as discovery occurs when an Elasticsearch node starts, restarts or loses contact with the master node for any reason. In those cases, the node needs to contact other nodes in the cluster to find the existing master node for the cluster or initiate the election of a new master node. 

How It Works

Upon startup, each node looks for other nodes, firstly by contacting those ip addresses of eligible master nodes held in previous cluster state.  If they are not available, it will look for nodes based upon the seed host providers mechanisms available.

Seed host providers may be defined in 3 ways: list based, file based or plugin based.  All of these methods will provide a list of IP addresses or hostnames which the node should contact in order to obtain a list of master eligible nodes.  The node will contact all of these addresses in turn, until either an active master is found, or failing that, until sufficient nodes can be found to elect a new master node.

Examples

The simplest form is to define a list of seed host providers in elasticsearch.yml

discovery.seed_hosts:
   - 192.168.1.10:9300
   - 192.168.1.11 
   - seeds.mydomain.com

An alternative way is to refer to a file using the following setting:

discovery.seed_providers: file

The file MUST be placed in the following filepath: $ES_PATH_CONF/unicast_hosts.txt

10.10.10.5
10.10.10.6:9305
10.10.10.5:10005
# an IPv6 address
[2001:0db8:85a3:0000:0000:8a2e:0370:7334]:9301

Note that the use of a port is optional. If not used, then the default port range of 9300-9400 will be used.

If you use AWS or  GCS then you can install and use a PLUGIN to obtain a list of seed hosts from an API.  A plugin also exists for Azure but is deprecated since version 5.

AWS Plugin

A typical configuration could be as follows:

discovery.seed_providers: ec2
discovery.ec2.tag.role: master
discovery.ec2.tag.environment: dev
discovery.ec2.endpoint: ec2.us-east-1.amazonaws.com
cloud.node.auto_attributes: true
cluster.routing.allocation.awareness.attributes: aws_availability_zone

The above configuration would look for all nodes with a tag called “environment” set to “dev” and a tag called “role” set to “master”, in the AWS zone us-east-1. The last two lines set up cluster routing allocation awareness based upon aws availability zones. (Not necessary, but nice to have).

GCE Plugin

A typical configuration could be as follows:

discovery.seed_providers: gce
cloud.gce.project_id: <your-google-project-id>
cloud.gce.zone: <your-zone>
discovery.gce.tags: <my-tag-name>

The above configuration would look for all virtual machines inside your project, zone and with a tag set to the tag name you provide.

Notes and good things to know

Cluster formation depends on correct setup of the network.host settings in elasticsearch.yml.  Make sure that the nodes can reach each other across the network using the IP address / hostname you are using, and are not getting blocked due to firewall settings on the ports required.


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 failed to send join request to master elastic search 5.4 cluster 5 4.97 K 

2 Github Issue Number 25860    


Log Context

Log ”Failed to send join request to master [{}]; reason [{}]; tried [{}] times” classname is ZenDiscovery.java
We have extracted the following from Elasticsearch source code to get an in-depth context :

                 return true;
            } catch (Exception e) {
                final Throwable unwrap = ExceptionsHelper.unwrapCause(e);
                if (unwrap instanceof NotMasterException) {
                    if (++joinAttempt == this.joinRetryAttempts) {
                        logger.info("failed to send join request to master [{}]; reason [{}]; tried [{}] times"; masterNode;
                            ExceptionsHelper.detailedMessage(e); joinAttempt);
                        return false;
                    } else {
                        logger.trace("master {} failed with [{}]. retrying... (attempts done: [{}])"; masterNode;
                            ExceptionsHelper.detailedMessage(e); joinAttempt);






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