K
Q

Kubernetes how to make Deployment to update image

11/1/2016

I do have deployment with single pod, with my custom docker image like:

containers:
  - name: mycontainer
    image: myimage:latest

During development I want to push new latest version and make Deployment updated. Can't find how to do that, without explicitly defining tag/version and increment it for each build, and do

kubectl set image deployment/my-deployment mycontainer=myimage:1.9.1
-- abovesun
docker
kubernetes

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6 Answers

11/1/2016

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.

-- Camil
Source: StackOverflow
8/14/2018

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/v1beta1
kind: Deployment
metadata:
  name: demo
spec:
  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.yml
kubectl 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.

-- Przemek Nowak
Source: StackOverflow
10/21/2019
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.

-- Martin Peter
Source: StackOverflow
5/16/2019

I use Gitlab-CI to build the image and then deploy it directly to GCK. If use a neat little trick to achieve a rolling update without changing any real settings of the container, which is changing a label to the current commit-short-sha.

My command looks like this:

kubectl patch deployment my-deployment -p "{\"spec\":{\"template\":{\"metadata\":{\"labels\":{\"build\":\"$CI_COMMIT_SHORT_SHA\"}}}}}}"

Where you can use any name and any value for the label as long as it changes with each build.

Have fun!

-- David Faber
Source: StackOverflow
1/17/2019

It seems that k8s expects us to provide a different image tag for every deployment. My default strategy would be to make the CI system generate and push the docker images, tagging them with the build number: xpmatteo/foobar:456.

For local development it can be convenient to use a script or a makefile, like this:

# create a unique tag    
VERSION:=$(shell date +%Y%m%d%H%M%S)
TAG=xpmatteo/foobar:$(VERSION)

deploy:
    npm run-script build
    docker build -t $(TAG) . 
    docker push $(TAG)
    sed s%IMAGE_TAG_PLACEHOLDER%$(TAG)% foobar-deployment.yaml | kubectl apply -f - --record

The sed command replaces a placeholder in the deployment document with the actual generated image tag.

-- xpmatteo
Source: StackOverflow
1/25/2020

I am using Azure DevOps to deploy the containerize applications, I am easily manage to overcome this problem by using the build ID

Everytime its builds and generate the new Build ID, I use this build ID as tag for docker image here is example

imagename:buildID

once your image is build (CI) successfully, in CD pipeline in deployment yml file I have give image name as

imagename:env:buildID

here evn:buildid is the azure devops variable which having value of build ID.

so now every time I have new changes to build(CI) and deploy(CD).

please comment if you need build definition for CI/CD.

-- Noman Sadiq
Source: StackOverflow