*** This is a working in progress project ***
Basically we will migrate this project from Netflix OOS to Kubernates This project will contain:
- Centralized authentication (JWT)
- Centralized log with ELK
- Centralized monitoring with Prometheus
- Infrastructure management with Kubernates
- Service mesh with Istio
- Microservices communication with GRPC
- Continuous integration
- Event sourcing
- Front-end with Angular
You can deploy all your apps by running the below bash command:
./kubectl-apply.sh
Use these commands to find your application's IP addresses:
$ kubectl get svc store -n jhipster
You can scale your apps using
$ kubectl scale deployment <app-name> --replicas <replica-count> -n jhipster
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 jhipster
Using livenessProbes and readinessProbe allow you to tell Kubernetes about the state of your applications, in order to ensure availablity of your services. You will need minimum 2 replicas for every application deployment if 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.
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 applications 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 applications 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 is 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.