First thing to do is get familiar with keycloak. once you are happy it might be useful take a look at the keycloak quickstarts.
They seem to have all the examples and samples on getting going with keycloak.

In particular you want to look at the keycloak examples

For posterity I will show the contents of keycloak.yaml:

apiVersion: v1
kind: Service
metadata:
  name: keycloak
  labels:
    app: keycloak
spec:
  ports:
  - name: http
    port: 8080
    targetPort: 8080
  selector:
    app: keycloak
  type: LoadBalancer
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: keycloak
  namespace: default
  labels:
    app: keycloak
spec:
  replicas: 1
  selector:
    matchLabels:
      app: keycloak
  template:
    metadata:
      labels:
        app: keycloak
    spec:
      containers:
      - name: keycloak
        image: quay.io/keycloak/keycloak:10.0.1
        env:
        - name: KEYCLOAK_USER
          value: "admin"
        - name: KEYCLOAK_PASSWORD
          value: "admin"
        - name: PROXY_ADDRESS_FORWARDING
          value: "true"
        ports:
        - name: http
          containerPort: 8080
        - name: https
          containerPort: 8443
        readinessProbe:
          httpGet:
            path: /auth/realms/master
            port: 8080

and keycloak-ingress.yaml:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: keycloak
spec:
  tls:
    - hosts:
      - KEYCLOAK_HOST
  rules:
  - host: KEYCLOAK_HOST
    http:
      paths:
      - backend:
          serviceName: keycloak
          servicePort: 8080

Environment Variables

We want to customise a few things about how keycloak runs and we do this by updating the environment variables.
So let us find what environment variabels are available and which we need to change.

We know the image beind used it:

quay.io/keycloak/keycloak:10.0.1

So lets see what the readme of that container image says

It is rather dissapointing that when we check on quay for keycloak, there is an empty readme. So our princess is in another castle.

The best readme I could find was on keycloak-containers.

So the list of available environment variables I could find were:

• KEYCLOAK_USER
• KEYCLOAK_PASSWORD
• DB_VENDOR - h2, postgres, mysql, mariadb, oracle, mssql
• DB_ADDR - database hostname
• DB_PORT - optoinal defaults to vendor port
• DB_DATABASE - database name
• DB_SCHEMA - only postgres uses this
• DB_USER - user to auth with db
• DB_PASSWORD - user password to auth with db
• KEYCLOAK_FRONTEND_URL - A set fixed url for frontend requests
• KEYCLOAK_LOGLEVEL
• ROOT_LOGLEVEL - ALL, DEBUG,ERROR, FATAL, INFO, OFF, TRACE and WARN
• KEYCLOAK_STATISTICS - db,http or all

Oh I found an even more exhaustive list of environment variables in the docker entrypoint

Creating a K8s service as a reference to an external servie

As per kubernetes up and running, it is worthwhile to represent an external service in kubernetes. That way you get built in naming, service discovery and it looks like the database is a k8s service.

It also helps when replacing a service or switching between prod and test.

my-db.yaml:

kind: Service
apiVersion: v1
metadata:
  name: external-database
  namespace: prod
spec:
  type: ExternalName
  externalName: database.company.com

If you just have an ip you need to create the service and the endpoint with:

kind: Service
apiVersion: v1
metadata:
  name: keycloak-external-db-ip
spec:
  ports:
    - protocol: TCP
      port: 3306
      targetPort: 3306

kind: Endpoints
apiVersion: v1
metadata:
  name: keycloak-external-db-ip
subsets:
  - addresses:
    - ip: my-ip.example.com
    ports:
    - port: 3306

now the actual service dns name will be:

    my-svc.my-namespace.svc.cluster.local

so in this case:

    keycloak-external-db-ip.keycloak.svc.cluster.local

Set that as DB_ADDR with the other credentials and we should be good to go.

So updarte that and the other environment variables and deploy:

Create the deployment:

kubectl create -f keycloak-deployment.yml -n keycloak

create the service and the ingress:

kubectl apply -f keycloak-service.yml -n keycloak
kubectl apply -f keycloak-ingress.yml -n keycloak

Boom and you should be up and running

Sources

• Kubernetes services
• kubernetes containers
• Brendan Burns. “Kubernetes: Up and Running.”
• Stian Thorgenson from Keycloak video on setting up on K8S
• K8s Mapping external services