How to resolve `kubectrl apply`deployment conflict error

Symton

When you try to apply a deployment yaml file to kubernetes cluster, you get the error:

kubectl apply -f tmp.yaml

The Deployment "xxx" is invalid:
* spec.template.spec.containers[0].env[53].valueFrom: Invalid value: "": may not be specified when `
value
` is not empty

Analysis

The kubernetes api met some issues when diff your tmp.yaml with the current running deployment.

For example, your current running deployment file has a hardcoded environment, and your new tmp.yaml has an environment whose value is reading from other sources:

# current running deployment
- name: EXPRESS_LOG_LEVEL
  value: debug

# You are trying to update to
- name: EXPRESS_LOG_LEVEL
  valueFrom:
    configMapKeyRef:
      name: xxx-configmap
      key: EXPRESS_LOG_LEVEL

How do I manually diff?

You can export the current deployment yaml by:

kubectl get deploy/your-current-deploy -o yaml | pbcopy

Then you can diff them via https://www.diffchecker.com/diff .

Solution

Delete the conflicted environments and then apply again:

KUBE_EDITOR="vim" kubectl edit deploy/your-current-deploy

kubectl apply -f tmp.yaml

# Now you get the success message!
deployment.apps/xxx-app configured

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