kubernetes: kubectl patch cannot patch a json list of items, only a single item

What happened: I am applying a patch to an existing pod. This patch is an add operation of type json with includes a list of items to add. Example:

kubectl patch pod alpine-correct --type='json' -p='[{"op":"add","path":"/metadata/annotations", "value":{"testone.annotation.io":"test-one"}},{"op":"add","path":"/metadata/annotations","value":{"testtwo.annotation.io":"test-two"}},{"op":"add","path":"/metadata/annotations","value":{"testthree.annotation.io":"test-three"}}]'

Results in: pod/alpine-correct patched I ran kubectl describe pod alpine-correct

Before the patch there were 0 annotations, now there was 1: testthree.annotation.io":"test-three"

What you expected to happen: I expected all three annotations to get added.

How to reproduce it (as minimally and precisely as possible):

Create an alpine pod (kubectl apply -f alpine-correct.yaml)
Run the patch above
Kubectl describe the pod and observe

The alpine pod spec:

apiVersion: v1
kind: Pod
metadata:
  name: alpine-correct
spec:
  containers:
  - image: alpine:3.2
    command:
      - /bin/sh
      - "-c"
      - "sleep 60m"
    imagePullPolicy: IfNotPresent
    name: alpine
  restartPolicy: Always

Anything else we need to know?:

Environment:

Kubernetes version (use kubectl version): 1.13
Cloud provider or hardware configuration: GCP

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 16 (9 by maintainers)

Most upvoted comments

@natalysheinin I suppose it is working as expected according to this RFC 6902 If you want to add 3 annotations to your pod you can run the following command:

kubectl patch pod alpine-correct --type='json' -p='[{"op":"add","path":"/metadata/annotations", "value":{"testone.annotation.io":"test-one","testtwo.annotation.io":"test-two","testthree.annotation.io":"test-three"}}]'

This command would patch the /metadata/annotations object with that value you provide.

In your prior execution,

kubectl patch pod alpine-correct --type='json' -p='[{"op":"add","path":"/metadata/annotations", "value":{"testone.annotation.io":"test-one"}},{"op":"add","path":"/metadata/annotations","value":{"testtwo.annotation.io":"test-two"}},{"op":"add","path":"/metadata/annotations","value":{"testthree.annotation.io":"test-three"}}]'

each operation was overriding the metadata/annotations object with the value in that operation, the final state of the pod’s annotations was the result of the last override in your patch operations array.

thesattiraju on Jan 8, 2019

this is an example of patching multiple paths that works as expected:

kubectl patch ns default --type=json -p '[
{"op":"add","path":"/metadata/annotations","value":{"a":"1","b":"2"}},
{"op":"add","path":"/metadata/labels","value":{"c":"3"}}
]'

/close

liggitt on Jan 8, 2019

see https://datatracker.ietf.org/doc/html/rfc6901#section-3

slash in keys is expressed as ~1

liggitt on Jun 29, 2021

API documentation is at https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.13/, and each object has a list of fields with links to the schema for that field

For example, pods: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.13/#pod-v1-core

liggitt on Jan 8, 2019