Build

In order to build the example Docker image, build the openliberty-postgres image, first:

$> cd liberty-postgres/
$> docker build -t openliberty-postgres:1 .

Then you can build the actual project:

$> mvn clean package
$> docker build -t config-example:1 .

Run

In order to run the application in a Docker container, it needs the database credentials at runtime. We need access to them locally, without storing them under VCS. We can create the file via command line:

$> cat << EOM > /tmp/bootstrap.properties
config-example.db.username=postgres
config-example.db.password=postgres
EOM

In order to run the Docker containers locally, execute ./docker-run-local.sh. As a prerequisite, you need to create a Docker network first:
docker network create --subnet=192.168.42.0/24 dkrnet

Kubernetes deployment

The Kubernetes deployments expects a secret that contains the database credentials. In order to avoid storing the credentials under VCS, we create the secret via command line:

$> kubectl create secret generic database-credentials --from-file=/tmp/bootstrap.properties

Once the secret database-credentials has been created, we can deploy our Kubernetes application via the definition under deployment/config-example.yaml. Please be aware that a Postgres database is expected to be resolvable under the hostname config-example-db in the default Kubernetes namespace. You can either deploy a Postgres database in the same namespace, or use a headless service to point to an external address.

Run Prometheus on Kubernetes

In order to run the Prometheus example on Kubernetes, simply apply all files in the deployment/ directory to your cluster after you have created the database-credentials secret.

kubectl apply -f deployment/

This will create the services and deployments for the example-config application, example-config-db database, Prometheus and Grafana instances, and required RBAC roles.

Also have a look at this blog post on how to discover applications running on Kubernetes with Prometheus.