kubectl Usage Conventions
Recommended usage conventions for
kubectl in Reusable Scripts
For a stable output in a script:
- Request one of the machine-oriented output forms, such as
-o go-template, or
- 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.
- Specify the
--generatorflag to pin to a specific behavior when you use generator-based commands such as
- Don’t rely on context, preferences, or other implicit states.
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
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
--recordto 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
- Pin to a specific generator version, such as
kubectl run --generator=deployment/v1beta1.
You can create the following resources using
kubectl run with the
|Resource||api group||kubectl command|
|Replication controller (deprecated)||v1|
kubectl run --generatorexcept for
run-pod/v1is deprecated in v1.12.
If you do not specify a generator flag, other flags prompt you to use a specific generator. The following table lists the flags that force you to use specific generators, depending on the version of the cluster:
|Generated Resource||Cluster v1.4 and later||Cluster v1.3||Cluster v1.2||Cluster v1.1 and earlier|
Note: These flags use a default generator only when you have not specified any flag. This means that when you combine
--generatorwith other flags the generator that you specified later does not change. For example, in a cluster v1.4, if you initially specify
--restart=Always, a Deployment is created; if you later specify
--generator=run/v1, a Replication Controller is created. This enables you to pin to a specific behavior with the generator, even when the default generator is changed later.
The flags set the generator in the following order: first the
--schedule flag, then the
--restart policy flag, and finally the
To check the final resource that was created, use the
flag, which only prints the object that would be sent to the cluster without really sending it.
- You can use
kubectl applyto create or update resources. For more information about using kubectl apply to update resources, see Kubectl Book.
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