configuremasters CLI command

Use this command to configure or modify masters in the Indexer cluster.

While installing the Indexers you can enable any one node as the master. After you set up the Indexer cluster, run this CLI command to configure additional nodes as the master or replace the current master node.

Each time you run this command, you must provide details of all the nodes that act as master nodes. For example, to retain the current master node and configure another node to act as a master node, while running this command, provide details for both the current master and the additional master. Generally, the minimum number of master nodes should be configured to a quorum (majority) of n/2 + 1 where n is the number of master eligible nodes for the cluster. If there are two nodes then n/2+1 = 2. That means, for the cluster to be completely functional, both the master eligible nodes should be running, but if there are three master eligible nodes then n/2 + 1 = 2, it means that even if one master eligible node is not functional due to some reasons, the cluster would be still functional.

Recommendation

Use the following recommendation as a guideline to decide the number of Indexers that must act as masters:

  • If the Indexer cluster contains upto two Indexers: At a minimum, one Indexer must act as master. However, if you have two regular nodes, you are in a conundrum. A quorum (majority of master eligible nodes) would be 2, but this means that a loss of one node will make your cluster inoperable. A setting of 1 will allow your cluster to function, but doesn’t protect against split brain (the existence of two masters in a single cluster). It is best to have a minimum of three nodes in situations like this.
  • If the Indexer cluster contains three or more Indexers: At a minimum, three Indexers must act as masters.

To understand the syntax and examples, see:

Related topic

configureredundancy-CLI-command

Syntax

Note

Before you run the command, note the following points:

configuremasters -d <hostname> -p <portNumber> -n <masterNodeDetails> -u <username> -w <password> [-l <locale>] [-s]
  • Angle brackets (< >) indicate a variable value that needs to be user defined.
  • Square brackets ([ ]) indicate optional parameters.

The following table describes the parameters used in the syntax:

Example inputs

The following example provides the input for configuring win-pun-01 and win-pun-02 as masters in the Indexer environment. 

configuremasters -u admin -w admin12345 -d localhost -p 9797 -n win-pun-01:9300, win-pun-02:9300

 

 

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