JHipster generated kubernetes configuration
Preparation
You will need to push your image to a registry. If you have not done so, use the following commands to tag and push the images:
$ docker image tag mytest anyobject/mytest
$ docker push anyobject/mytest
Deployment
You can deploy all your apps by running the below bash command:
./kubectl-apply.sh
Exploring your services
Use these commands to find your application's IP addresses:
$ kubectl get svc mytest -n mytest
Scaling your deployments
You can scale your apps using
$ kubectl scale deployment <app-name> --replicas <replica-count> -n mytest
zero-downtime deployments
The default way to update a running app in kubernetes, is to deploy a new image tag to your docker registry and then deploy it using
$ kubectl set image deployment/<app-name>-app <app-name>=<new-image> -n mytest
Using livenessProbes and readinessProbe allows you to tell kubernetes about the state of your apps, in order to ensure availablity of your services. You will need minimum 2 replicas for every app deployment, you want to have zero-downtime deployed. This is because the rolling upgrade strategy first kills a running replica in order to place a new. Running only one replica, will cause a short downtime during upgrades.
Monitoring tools
JHipster console
Your application logs can be found in JHipster console (powered by Kibana). You can find its service details by
$ kubectl get svc jhipster-console -n mytest
- If you have chosen Ingress, then you should be able to access Kibana using the given ingress domain.
- If you have chosen NodePort, then point your browser to an IP of any of your nodes and use the node port described in the output.
- If you have chosen LoadBalancer, then use the IaaS provided LB IP
Troubleshooting
my apps doesn't get pulled, because of 'imagePullBackof'
check the registry your kubernetes cluster is accessing. If you are using a private registry, you should add it to your namespace by kubectl create secret docker-registry (check the docs for more info)
my apps get killed, before they can boot up
This can occur, if your cluster has low resource (e.g. Minikube). Increase the initialDelySeconds value of livenessProbe of your deployments
my apps are starting very slow, despite I have a cluster with many resources
The default setting are optimized for middle scale clusters. You are free to increase the JAVA_OPTS environment variable, and resource requests and limits to improve the performance. Be careful!
my SQL based microservice stuck during liquibase initialization when running multiple replicas
Sometimes the database changelog lock gets corrupted. You will need to connect to the database using kubectl exec -it and remove all lines of liquibases databasechangeloglock table.