Chapter 3. Command Line Client

In this chapter I’m going to introduce some key terms and concepts you’ll hear continuously throughout the book. Each title below will introduce and explain the concept, and (if applicable) the plugin which implements its usage.

The most common way to interact with mcollective is the mco command-line client, which can be used interactively or in scripts. It’s also relatively easy to write other clients in Ruby, which can be used as backends for GUI apps or as glue in a reactive infrastructure. We’ll cover how to build your own clients in the Part III section of the book. In this chapter we’re going to focus on the command line client.

As I introduce each concept, I’ll show you command line usage that uses that feature. As we will only use the ping and find commands, these are safe to run in your own MCollective setup. Feel free to run each of them and see what results you receive.


For the communications from the client to reach your servers, the client utilizes two plugins:

  • A connector plugin to establish a link with the middleware and publish to topics
  • A security plugin to sign (and optionally encrypt) the data payload

These two connectors must be the same throughout your environment. Until such time as you enable authorization controls (outlined later in Chapter 11), the configuration for these plugins will be the same on every client host.

For the baseline setup described in Chapter 2 we used:

  • Connector plugin: ActiveMQ

    The alternative would ...

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