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kubectl Usage Conventions

Recommended usage conventions for kubectl.

Using kubectl in Reusable Scripts

For a stable output in a script:

  • Request one of the machine-oriented output forms, such as -o name, -o json, -o yaml, -o go-template, or -o jsonpath.
  • Fully-qualify the version. For example, jobs.v1.batch/myjob. This will ensure that kubectl does not use its default version that can change over time.
  • Don’t rely on context, preferences, or other implicit states.

Best Practices

kubectl run

For kubectl run to satisfy infrastructure as code:

  • Tag the image with a version-specific tag and don’t move that tag to a new version. For example, use :v1234, v1.2.3, r03062016-1-4, rather than :latest (For more information, see Best Practices for Configuration).
  • Capture the parameters in a checked-in script, or at least use --record to annotate the created objects with the command line for an image that is lightly parameterized.
  • Check in the script for an image that is heavily parameterized.
  • Switch to configuration files checked into source control for features that are needed, but not expressible via kubectl run flags.
Resource api group kubectl command
Pod v1
Replication controller (deprecated) v1
Deployment (deprecated) extensions/v1beta1
Deployment (deprecated) apps/v1beta1
Job (deprecated) batch/v1
CronJob (deprecated) batch/v1beta1
CronJob (deprecated) batch/v2alpha1
Generated Resource Cluster v1.4 and later Cluster v1.3 Cluster v1.2 Cluster v1.1 and earlier
Pod --restart=Never --restart=Never --restart=OnFailure OR --restart=Never
Replication Controller --restart=Always
Deployment --restart=Always --restart=Always --restart=Always N/A
Job --restart=OnFailure --restart=OnFailure --restart=OnFailure OR --restart=Never N/A
Cron Job --schedule=<cron> N/A N/A N/A
--restart=Always, a Deployment is created; if you later specify --restart=Always

To check the final resource that was created, use the --dry-run flag, which only prints the object that would be sent to the cluster without really sending it.

kubectl apply

  • You can use kubectl apply to create or update resources. For more information about using kubectl apply to update resources, see Kubectl Book.

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