Universal Container Runtime

Universal Container Runtime

The Universal Container Runtime (UCR) launches Mesos containers from binary executables and extends the Mesos container runtime to support provisioning Docker images. The UCR has many advantages over the Docker Engine for running Docker images. Use the Docker Engine only if you need specific features of the Docker package.

Provision a container with the UCR from the DC/OS web interface

  1. Click the Services tab of the DC/OS web interface, then click RUN A SERVICE.

  2. Click Single Container.

  3. Enter the service ID.

  4. In the CONTAINER IMAGE field, optionally enter a container image. Otherwise, enter a command in the COMMAND field.

  5. Specify the UCR. Click MORE SETTINGS. In the Container Runtime section, choose the UNIVERSAL CONTAINER RUNTIME (UCR) radio button.

  6. Click REVIEW & RUN and RUN SERVICE.

Provision a container with the UCR from the DC/OS CLI

  1. In your Marathon application definition, set the container.type parameter to MESOS. Here, we specify a Docker container with the docker object. The UCR provides an optional pullConfig parameter to enable you to authenticate to a private Docker registry.
{
  "id": "/nginx-bridge",
  "container": {
    "portMappings": [
      {
        "containerPort": 80,
        "hostPort": 0,
        "labels": {
          "VIP_0": "/nginx2:1024"
        },
        "protocol": "tcp",
        "servicePort": 10000,
        "name": "webport"
      }
    ],
    "type": "MESOS",
    "volumes": [],
    "docker": {
        "image": "nginx",
        "forcePullImage": false,
        "pullConfig": {
            "secret": "pullConfigSecret"
        },
        "parameters": []
        }
    },
    "secrets": {
      "pullConfigSecret": {
        "source": "/mesos-docker/pullConfig"
      }
    },
    "args":[  
    "<my-arg>"
    ],
    "cpus": 0.5,
    "disk": 0,
    "instances": 1,
    "mem": 128,
    "networks": [
      {
      "mode": "container/bridge"
      }
    ],
    "requirePorts": false
}

Important: If you leave the args field empty, the default entry point will be the launch command for the container. If your container does not have a default entry point, you must specify a command in the args field. If you do not, your service will fail to deploy.

Limitations

  • The UCR is a preview feature in DC/OS 1.10.
  • The UCR does not support the following: runtime privileges, Docker options, private registries with container authentication.

Further Reading