Kubernetes how to make Deployment to update image

You can configure your pod with a grace period (for example 30 seconds or more, depending on container startup time and image size) and set "imagePullPolicy: "Always". And use kubectl delete pod pod_name.A new container will be created and the latest image automatically downloaded, then the old container terminated.

Example:

spec:  terminationGracePeriodSeconds: 30  containers:  - name: my_container    image: my_image:latest    imagePullPolicy: "Always"

I'm currently using Jenkins for automated builds and image tagging and it looks something like this:

kubectl --user="kube-user" --server="https://kubemaster.example.com"  --token=$ACCESS_TOKEN set image deployment/my-deployment mycontainer=myimage:"$BUILD_NUMBER-$SHORT_GIT_COMMIT"

Another trick is to intially run:

kubectl set image deployment/my-deployment mycontainer=myimage:latest

and then:

kubectl set image deployment/my-deployment mycontainer=myimage

It will actually be triggering the rolling-update but be sure you have also imagePullPolicy: "Always" set.

Update:

another trick I found, where you don't have to change the image name, is to change the value of a field that will trigger a rolling update, like terminationGracePeriodSeconds. You can do this using kubectl edit deployment your_deployment or kubectl apply -f your_deployment.yaml or using a patch like this:

kubectl patch deployment your_deployment -p \  '{"spec":{"template":{"spec":{"terminationGracePeriodSeconds":31}}}}'

Just make sure you always change the number value.

UPDATE 2019-06-24

Based on the @Jodiug comment if you have a 1.15 version you can use the command:

kubectl rollout restart deployment/demo

Read more on the issue:

https://github.com/kubernetes/kubernetes/issues/13488

Well there is an interesting discussion about this subject on the kubernetes GitHub project. See the issue: https://github.com/kubernetes/kubernetes/issues/33664

From the solutions described there, I would suggest one of two.

First

1.Prepare deployment

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: demospec:  replicas: 1  template:    metadata:      labels:        app: demo    spec:      containers:      - name: demo        image: registry.example.com/apps/demo:master        imagePullPolicy: Always        env:        - name: FOR_GODS_SAKE_PLEASE_REDEPLOY          value: 'THIS_STRING_IS_REPLACED_DURING_BUILD'

2.Deploy

sed -ie "s/THIS_STRING_IS_REPLACED_DURING_BUILD/$(date)/g" deployment.ymlkubectl apply -f deployment.yml

Second (one liner):

kubectl patch deployment web -p \  "{\"spec\":{\"template\":{\"metadata\":{\"labels\":{\"date\":\"`date +'%s'`\"}}}}}"

Of course the imagePullPolicy: Always is required on both cases.

kubectl rollout restart deployment myapp

This is the current way to trigger a rolling update and leave the old replica sets in place for other operations provided by kubectl rollout like rollbacks.