juliuskrah / quarkus-liquibase

In a kubernetes deployment, a pod must start as fast as possible in order to scale on demand. Running a liquibase migration as part of application startup lends itself to a slower startup. This repository shows how to do this with init-containers

Running Liquibase in the Cloud using Kubernetes

This project contains a demo for running Liquibase migration as an init container in a Kubernetes environment

Getting started

Before you're able to run this demo, you need the following already setup on your development environment

• Kubernetes: either one of the following
  • kind
  • minikube
  • Docker Desktop with Kubernetes enabled on Mac or PC
• helm
• cURL

Running the application in dev mode

You can run your application in dev mode that enables live coding using:

./mvnw compile quarkus:dev

The following operations have been defined

1. GET http://localhost:8080/clients/:id

   curl --location --request GET 'http://localhost:8080/clients/ce74d8f2-ef49-4f2a-b5cc-52ef30046d40'

2. GET http://localhost:8080/clients

   curl --location --request GET 'http://localhost:8080/clients'

3. POST http://localhost:8080/clients

   curl --location --request POST 'http://localhost:8080/clients' \
   --header 'Content-Type: application/json' \
   --data-raw '{
       "name": "evil corp",
       "code": "EVIL",
       "contactPerson": "Tyrell Wellick"
   }'

4. GET http://localhost:8080/clients/:code/code

   curl --location --request GET 'http://localhost:8080/clients/acme/code'

5. GET http://localhost:8080/clients/:clientCode/services

   curl --location --request GET 'http://localhost:8080/clients/acme/services'

NOTE: Quarkus now ships with a Dev UI, which is available in dev mode only at http://localhost:8080/q/dev/.

Preparing the Application to run in Kubernetes

The following sections contain instructions on how to:

1. Build a native docker image
2. Install Postgres operator

Building a native docker image

./mvnw package -Pnative -Dquarkus.native.container-build=true -Dquarkus.container-image.build=true

This will result in a docker image with name ${quarkus.container-image.group}/${quarkus.container-image.name}:${version}. The following properties are defined in application.properties

quarkus.container-image.group=juliuskrah
quarkus.container-image.name=liquibase-kubernetes

Install PostgreSQL Operator

The following commands will be issued to install the PostgreSQL Operator.

# add repo for postgres-operator
helm repo add postgres-operator-charts https://opensource.zalando.com/postgres-operator/charts/postgres-operator

# install the postgres-operator
helm install postgres-operator postgres-operator-charts/postgres-operator

# add repo for postgres-operator-ui
helm repo add postgres-operator-ui-charts https://opensource.zalando.com/postgres-operator/charts/postgres-operator-ui

# install the postgres-operator-ui
helm install postgres-operator-ui postgres-operator-ui-charts/postgres-operator-ui

Start the Database Cluster

We will start the PostgreSQL database cluster example-liquibase-cluster

kubectl apply -f k8s/data

Check all components are coming up

# check the deployed cluster
kubectl get postgresql

# check created database pods
kubectl get pods -l application=spilo -L spilo-role

# check created service resources
kubectl get svc -l application=spilo -L spilo-role

Start the Application Workload

Now we're ready to start our application

kubectl apply -f k8s/app

Check all components are coming up

kubectl get pods -l 'app.kubernetes.io/name=liquibase-on-kubernetes'

You should see output similar to what is below

NAME                                       READY   STATUS     RESTARTS   AGE
liquibase-on-kubernetes-667678855d-qmwdj   0/1     Init:0/1   0          4s

Take note of the name of the pod and run the command to follow the logs of the liquibase migration

Replace <pod-name> with the pod name noted earlier

kubectl logs --follow pod/<pod-name> -c liquibase-migration

If all is good, you can port forward

kubectl port-forward services/liquibase-on-kubernetes 8080:80