Kubernetes how to make Deployment to update image

Question

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

User · Answer

Another option which is more suitable for debugging but worth mentioning is to check in revision history of your rollout:

$ kubectl rollout history deployment my-dep
deployment.apps/my-dep
 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

To see the details of each revision, run:

 kubectl rollout history deployment my-dep --revision=2

And then returning to the previous revision by running:

 $kubectl rollout undo deployment my-dep --to-revision=2

And then returning back to the new one.
Like running ctrl+z -> ctrl+y (:

(*) The CHANGE-CAUSE is <none> because you should run the updates with the --record flag - like mentioned here:

kubectl set image deployment/nginx-deployment nginx=nginx:1.16.1 --record

(**) There is a discussion regarding deprecating this flag.

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

[docker] Kubernetes how to make Deployment to update image

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