how to replace or find correct path for kustomize

Question

I have deployment and I want to replace "path" value in liveness probe section. What is correct path for this in kustomize?

- patch: |-
    - op: replace
      path: ??????????
      value:
        https://xyz.staging.something.eu/ping

---

    apiVersion: v1
    kind: Pod
    metadata:
      labels:
        test: liveness
      name: liveness-http
    spec:
      containers:
      - name: liveness
        image: k8s.gcr.io/liveness
        args:
        - /server
        livenessProbe:
          httpGet:
            path: /healthz
            port: 8080
          initialDelaySeconds: 3
          periodSeconds: 3

Answer 1

It is the yaml path. You follow the nodes from the parent down to the leaf-node you want to specify.

Since you want the path node on httpGet of livenessProbe it will end with livenessProbe.httpGet.path .

The parent node of livenessProbe is a bit trickier, notice it is an element of the list containers . You can specify it either through an index or through an attribute (EG name ). So either containers[0] or containers[name=liveness] .

By now we have containers[0].livenessProbe.httpGet.path . The missing root node is spec , so spec.containers[0].livenessProbe.httpGet.path will do it.

There is a bunch of other ways that this could be expressed as well. https://github.com/wwkimball/yamlpath#illustration seems like a good more in-depth explanation.

Answer 2

I am trying out the syntax containers[name=xx] and its failing when containers/0 works. I am not sure if im missing something or this is not supported, couldn't find any more examples about this syntax for Kustomize.

Below the details

Checked with kustomize versions:

• v4.5.4
• v4.5.2

test.yaml:

---
apiVersion: v1
kind: Pod
metadata:
  name: test-pod
spec:
  containers:
    - name: test-container
      env:
      - name: environment
        value: stage
      - name: api_port
        value: "8080"
      image: docker.io/bitname/posgresql:latest
      ...
      ...

kustomization.yaml

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

...
...

patchesJson6902:
- target:
    version: v1
    kind: Pod
    name: test-pod
  path: replace.yaml

replace.yaml

- op: replace
  path: "/spec/containers[name=test-container]/env/0/value"
  value: "dev"
# doesn't work: `Error: replace operation does not apply: doc is missing path" /spec/containers[name=test-container]/env/0/value: missing value
 

- op: replace
  path: "/spec/containers/0/env/0/value"
  value: "dev"
# works as expected

Thanks!