K
Q

kubernetes not applying new service update from docker

9/5/2018

I have a node JS app which i am deploying to kubernetes.

I have made changes to node JS app and am redeploying the app to K8s.

However, I notice that the deployment is not making through.

I checked my docker hub and yes the latest image is being deployed. This is my service.yaml file below

apiVersion: v1
kind: Service
metadata:
  name: fourthapp
spec:
  type: LoadBalancer #Exposes the service as a node port
  ports:
  - port: 3000
    protocol: TCP
    targetPort: 3000
  selector:
    app: webapp

and this is my deploy.yaml file

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: fourthapp
spec:
  replicas: 2
  template:
    metadata:
      labels:
        app: webapp
    spec:
      containers:
      - name: webapp
        image: index.docker.io/leexha/nodejsapp:latest
        ports:
        - containerPort: 3000
        resources:
          requests: 
            memory: 500Mi
            cpu: 0.5
          limits:
            memory: 500Mi
            cpu: 0.5
        imagePullPolicy: Always

when i run the service.yaml it reads

C:\Users\adrlee\Desktop\oracle\Web_projects>kubectl apply -f service.yml
service "fourthapp" unchanged

Anything im doing wrong?

-- Adam
docker
kubernetes

Similar Questions

kubernetes is un-able to pull large image from private repository in docker-hub
Kubernetes merges deleted job and new job
Open an external port into Istio - problem only on docker-for-mac
shortcut for typing kubectl --all-namespaces everytime
Create cluster wide service account to connect with gitlab
Is there any way to control read/write speed or IOPS limit per pod?

3 Answers

9/5/2018

Kubernetes won't update running pods unless the pod spec is changed. If you want force the deployment you can run after the apply command:

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

It will add/update special date annotation on the pod template and Kubernetes will update running pods.

-- Lauri
Source: StackOverflow
9/5/2018

If I understood the question you should update the Deployment instead. The service is just a kind of LB which dispatch traffic between your pods.

First, you should add imagePullPolicy: Always to the deployment to force k8s to download the newest image.

If you want to update the deployment you can run

kubectl apply -f deploy.yml

or performing a Rolling Update

-- Giorgio Cerruti
Source: StackOverflow
9/5/2018

If you don't give every build of your image a distinct name, it's hard to force Kubernetes to restart a Deployment when the underlying image changes: it has no way of knowing that the "latest" tag on Docker Hub now means something else. (imagePullPolicy: Always will at least force it to get a new image if it happens to be restarting anyways.) When your run kubectl apply, it looks at the Deployment you're uploading, sees that it matches what's already running, and does nothing.

Best practice is to not use the "latest" tag and give some sort of unique identifier (timestamp, source control commit ID, ...). Then you can update the image ID in the pod spec, kubectl apply will see that something is different, and Kubernetes will perform a rolling update of the running pod(s) for you. This also has the advantage that, if a build is bad, you can easily go backwards by changing the image tag back to a previous build.

-- David Maze
Source: StackOverflow