Kubectl patch: Difference between revisions
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=External= | =External= | ||
* https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#patch | * https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#patch | ||
* https://kubernetes.io/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch/ | |||
* https://kubernetes.io/docs/reference/using-api/server-side-apply | |||
=Internal= | =Internal= | ||
* [[Kubectl#Commands|kubectl]] | * [[Kubectl#Commands|kubectl]] | ||
* [[Kubernetes Strategic Merge Patch]] | |||
* [[JSON Merge Patch]] | |||
* [[JSON Patch]] | |||
=Overview= | =Overview= | ||
<code>kubectl patch</code> supports [[Kubernetes Strategic Merge Patch|strategic merge patch]]. | <code>kubectl patch</code> supports the following modes: [[Kubernetes Strategic Merge Patch|strategic merge patch]] ("strategic"), [[JSON_Merge_Patch|JSON merge patch]] ("merge") and [[JSON_Patch|JSON patch]] ("json"). | ||
=Caveats= | |||
⚠️There are situations when the patch apparently succeeds, the <code>kubectl patch</code> command exits with 0 and if the resource is queried immediately, the patch seems to be applied, but when the resource is queried a while later (15 secs), it becomes apparent that the "patch" did not take. This happened while trying to unbind a PV from the PVC while the PVC is still active. | |||
=Usage Examples= | =Usage Examples= | ||
==Delete a Field== | ==JSON Patch Usage Examples== | ||
===<span id='Delete_a_Field'></span>Delete a Field with a JSON Patch=== | |||
Unbind a PVC from a PV by deleting the PV's <code>claimRef</code>: | Unbind a PVC from a PV by deleting the PV's <code>claimRef</code>: | ||
<syntaxhighlight lang='bash'> | <syntaxhighlight lang='bash'> | ||
kubectl patch pv my-pv --type=json - | kubectl patch pv my-pv --type=json --patch='[{"op": "remove", "path": "/spec/claimRef"}]' | ||
</syntaxhighlight> | |||
===Update the Image on a Deployment=== | |||
Updates the <code>image</code> field of the first container in the containers array. | |||
<syntaxhighlight lang='bash'> | |||
kubectl patch deployment my-deployment --type=json --patch='[{"op": "replace", "path": "/spec/template/spec/containers/0/image", "value": "docker.io/ovidiufeodorov/httpd:test_2"}]' | |||
</syntaxhighlight> | </syntaxhighlight> | ||
Latest revision as of 18:15, 30 July 2021
External
- https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#patch
- https://kubernetes.io/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch/
- https://kubernetes.io/docs/reference/using-api/server-side-apply
Internal
Overview
kubectl patch supports the following modes: strategic merge patch ("strategic"), JSON merge patch ("merge") and JSON patch ("json").
Caveats
⚠️There are situations when the patch apparently succeeds, the kubectl patch command exits with 0 and if the resource is queried immediately, the patch seems to be applied, but when the resource is queried a while later (15 secs), it becomes apparent that the "patch" did not take. This happened while trying to unbind a PV from the PVC while the PVC is still active.
Usage Examples
JSON Patch Usage Examples
Delete a Field with a JSON Patch
Unbind a PVC from a PV by deleting the PV's claimRef:
kubectl patch pv my-pv --type=json --patch='[{"op": "remove", "path": "/spec/claimRef"}]'
Update the Image on a Deployment
Updates the image field of the first container in the containers array.
kubectl patch deployment my-deployment --type=json --patch='[{"op": "replace", "path": "/spec/template/spec/containers/0/image", "value": "docker.io/ovidiufeodorov/httpd:test_2"}]'