51. Openshift

Openshift is the RedHat public (and enterprise) PaaS solution. Like Heroku, it works by running scripts triggered by git commits, so you can script the launching of a Spring Boot application in pretty much any way you like as long as the Java runtime is available (which is a standard feature you can ask for at Openshift). To do this you can use the DIY Cartridge and hooks in your repository under .openshift/action_scripts:

The basic model is to:

  1. Ensure Java and your build tool are installed remotely, e.g. using a pre_build hook (Java and Maven are installed by default, Gradle is not)
  2. Use a build hook to build your jar (using Maven or Gradle), e.g.

    mvn package -s .openshift/settings.xml -DskipTests=true
  3. Add a start hook that calls java -jar …​

    nohup java -jar target/*.jar --server.port=${OPENSHIFT_DIY_PORT} --server.address=${OPENSHIFT_DIY_IP} &
  4. Use a stop hook (since the start is supposed to return cleanly), e.g.

    PID=$(ps -ef | grep java.*\.jar | grep -v grep | awk '{ print $2 }')
    if [ -z "$PID" ]
        client_result "Application is already stopped"
        kill $PID
  5. Embed service bindings from environment variables provided by the platform in your application.properties, e.g.

    spring.datasource.url: jdbc:mysql://${OPENSHIFT_MYSQL_DB_HOST}:${OPENSHIFT_MYSQL_DB_PORT}/${OPENSHIFT_APP_NAME}
    spring.datasource.username: ${OPENSHIFT_MYSQL_DB_USERNAME}
    spring.datasource.password: ${OPENSHIFT_MYSQL_DB_PASSWORD}

There’s a blog on running Gradle in Openshift on their website that will get you started with a gradle build to run the app. A bug in Gradle currently prevents you from using Gradle newer than 1.6.