Using jrctl In Clustered Environments

Introduction

This guide will cover the use of the jrctl tool, specifically in clustered environments. You can find our base article for using jrctl here.

Tags

In a clustered environment, every node has a tag. To view all of the nodes in your cluster and their tags, use the following command:

jrctl node list

This will list all the connected nodes in your cluster, along with their tags. Tags include:

• jump - The main node in the cluster which you have SSH access to, and where you can run jrctl.
• www - The node(s) that run Nginx and PHP-FPM which serve your web content.
• varnish - The node(s) that run the Varnish HTTP cache service.
• db - The node that runs your MariaDB/MySQL database.
• redis - The node that runs Redis services. Typically this is also your db node.
• search - The node that runs Elasticsearch/OpenSearch. This may also be your db node.

To list what services are running on nodes with a specific tag, use the following command as an example:

jrctl service list -t www

The above command will list all services running on all nodes that have the www tag.

To restart a service on nodes with a given tag, use a command such as:

jrctl service restart nginx -t www

The above command will restart the nginx service on all nodes with the www tag.