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Using Docker Images

Deis supports deploying applications via an existing Docker Image. This is useful for integrating Deis into Docker-based CI/CD pipelines.

Prepare an Application

Start by cloning an example application:

$ git clone https://github.com/deis/example-go.git
$ cd example-go
$ git checkout docker

Next use your local docker client to build the image and push it to DockerHub.

$ docker build -t <username>/example-go .
$ docker push <username>/example-go

Docker Image Requirements

In order to deploy Docker images, they must conform to the following requirements:

  • The Dockerfile must use the EXPOSE directive to expose exactly one port.
  • That port must be listening for an HTTP connection.
  • The Dockerfile must use the CMD directive to define the default process that will run within the container.
  • The Docker image must contain bash to run processes.

Create an Application

Use deis create to create an application on the controller.

$ mkdir -p /tmp/example-go && cd /tmp/example-go
$ deis create example-go --no-remote
Creating application... done, created example-go

!!! note For all commands except for deis create, the deis client uses the name of the current directory as the app name if you don't specify it explicitly with --app.

Deploy the Application

Use deis pull to deploy your application from DockerHub or a public registry.

$ deis pull gabrtv/example-go:latest
Creating build...  done, v2

$ curl -s http://example-go.local3.deisapp.com
Powered by Deis

Because you are deploying a Docker image, the cmd process type is automatically scaled to 1 on first deploy.

Use deis scale cmd=3 to increase cmd processes to 3, for example. Scaling a process type directly changes the number of Containers running that process.

Private Registry

To deploy Docker images from a private registry or from a private repository, use deis registry to attach credentials to your application. These credentials are the same as you'd use when running docker login at your private registry.

To deploy private Docker images, take the following steps:

  • Gather the username and password for the registry, such as a Quay.io Robot Account or a GCR.io Long Lived Token
  • Run deis registry:set username=<the-user> password=<secret> -a <application-name>
  • Now perform deis pull as normal, against an image in the private registry

When using a GCR.io Long Lived Token, the JSON blob will have to be compacted first using a tool like jq and then used in the password field in deis registry:set. For the username, use _json_key. For example:

deis registry:set username=_json_key password="$(cat google_cloud_cred.json | jq -c .)"

When using a private registry the docker images are no longer pulled into the Deis Internal Registry via the Deis Workflow Controller but rather is managed by Kubernetes. This will increase security and overall speed, however the port information can no longer be discovered. Instead the port information can be set via deis config:set PORT=80 prior to setting the registry information.

!!! note Currently GCR.io and ECR in short lived auth token mode are not supported.