Ansible Role: marathon-deploy

An Ansible role that helps deploying applications on marathon.

The core of the role is a module to support an operation like

- name: run application on marathon
  marathon: uri=http://marathon-node:8080 app_json='nginx.json' state=present

or like

- name: run application on marathon
  marathon: uri=http://marathon-node:8080 app='{{ var_describing_app | to_json }}' state=present

Requirements

The module shipping with the role is supposed to run on a node that can send REST requests to the marathon endpoint. Typically this could be the localhost.

The following python modules are needed:

• marathon

Usage

Among the various states supported by the module, all will require either one of the two following parameters:

• app_json: a path to a file (located on the machine to be managed) that contains the JSON application definition for Marathon to manage the app.
• app: a JSON-encoded object that describes the application for Marathon to manage.

Consult the Marathon documentation to grok the specification of the JSON objects that Marathon uses to describe applications.

Example Playbook

You will need to assign the marathon-deploy role to access the marathon module

- hosts: 127.0.0.1
  connection: local
  vars:
    app:
        id: prometheus
        instances: 1
        cpus: 1
        mem: 512
        container:
            type: "DOCKER"
            docker:
              image: "prom/prometheus:latest"
              network: "BRIDGE"
              privileged: false
              forcePullImage: true
              portMappings:
              - containerPort: 9090
                hostPort: 0
        healthChecks: []
        upgradeStrategy:
            maximumOverCapacity: 0
            minimumHealthCapacity: 0
        labels:
            "MARATHON_SINGLE_INSTANCE_APP": "true"
  roles:
    - marathon-deploy
  tasks:
    - name: run Prometheus on marathon
      marathon: uri=http://marathon-node:8080 app='{{ app | to_json }}' state=present