Altus Director Scripts

Altus Director needs to perform a small amount of work on an instance before running any scripts:

The first scripts that Altus Director runs are bootstrap scripts. Bootstrap scripts are run when an instance is first allocated and are used to perform work related to the lifecycle of the individual instance rather than the deployment or cluster lifecycle.

Deployment post-creation scripts are run after Cloudera Manager is running and configured, but before Altus Director updates itself with any changes Cloudera Manager may independently and automatically make to its own configuration. Similarly, cluster post-creation scripts run after Cloudera Manager is configured to manage the cluster, but before Altus Director updates itself with any changes Cloudera Manager may independently and automatically make to those configurations. In both cases, information that scripts draw from Altus Director might be out of date.

Altus Director selects an arbitrary cluster instance for running cluster post-creation and pre-terminate scripts. Therefore, these scripts should perform work that applies to the cluster lifecycle as a whole, and not individual instances in the cluster, since each script runs on just one instance. If, before all scripts are complete, a chosen arbitrary instance fails, for example due to an unexpected termination, Altus Director selects a new instance and resumes script execution.

Some scripts automatically have access to several environment variables defined by Altus Director alongside any others defined explicitly in script definitions. The variables are oriented to make it easy to perform API calls to Cloudera Manager.

A script should return exit code 0 if its execution should be considered successful by Altus Director. When a script returns a nonzero exit code, Altus Director retries the script up to a configurable number of times, in case the failure was due to a transient problem. When all script retries fail, Altus Director fails the process it is performing, such as bootstrapping a cluster. If a script returns a reserved exit code (configurable, default 91), Altus Director does not retry the script and fails its current process immediately.

Any type of script may be specified in a cluster configuration file to be used with the Altus Director client. A pair of fields in the appropriate template is available for providing each type of script. One field is for specifying scripts by directly including their content, and the other by referencing local file paths. See the table below to identify the specific field name for direct inclusion or path reference for each type of script. Both fields may be used for one type of script, in which case the scripts included directly are executed first. Each field value is a list of scripts, and so within a field, scripts are executed in the order they are given.

A script can be specified simply by a string containing its content (for direct inclusion) or its path (for reference by path). To also specify a script ID or environment variables, use an object with fields for those elements as well as the script content or path. The following example lists two bootstrap scripts by content, one as just the script itself, another as an object with a script ID and environment variables:

bootstrapScripts: ["""#!/bin/sh
echo 'Hello World!'
exit 0
""",
  {
    id: bootstrapScript2,
    env {
      KEY1: VALUE1
      KEY2: VALUE2
    },
    content: "echo The values are $KEY1 and $KEY2"
  }
]

See the reference configuration files for more examples.