Working with Docker

You can use Docker containers in patterns that you create in Cloud Pak System Software.

You can reference Docker images that are stored on Docker Hub or in a private Docker registry that runs on Cloud Pak System Software to create the Docker containers in the instance after the pattern is deployed.
Restriction:
  • Only Docker images that are in the private Docker registry are listed in the Pattern Builder. Even if a connection to Docker Hub exists, Docker images in Docker Hub are not displayed in the Pattern Builder. However, if you create the application model manually and deploy it without opening it in the Pattern Builder, the system is able to retrieve the Docker image from Docker Hub.
Complete these steps to configure the system for use with Docker:
  • Install and enable the Docker Pattern Type.
  • If needed, configure the system to reference a Docker registry:
    • If your system has external network access, no extra configuration is needed to reference Docker images on Docker Hub. If the system has external network access and no private Docker registry is referenced in the Docker system plug-in, the system connects to the public Docker Hub automatically.
      Note: Functions to link Docker containers in patterns are provided by the ambassador image. This image is included in the private Docker registry that you can deploy by using the steps in the following section. If you are using an existing Docker registry and you want to link Docker containers, upload the ambassador image manually to the existing Docker registry.
    • If your system does not have external network access, deploy a private Docker registry. For more information, see Deploying a private Docker registry.
  • If you deployed a private Docker registry, configure the system to use it. For more information, see Configuring the Docker plug-in for patterns.
  • Use Docker containers in patterns. For more information, see Working with Docker containers in patterns.
  • Administer instances that include Docker containers. For more information, see Administering instances that include Docker containers.
  • Optional: Convert existing Docker Compose/Fig template YML files for use in Cloud Pak System Software. For more information, see Converting a Docker Compose/Fig template YML file for use in Cloud Pak System Software.

Docker versions

These versions are included with the system:
  • Docker Community Edition (CE) 17.09.1.
  • Docker registry V2.2
Docker Trusted Registry V1.4.2 is tested for use with Cloud Pak System Software, but it is not included with the system.
Note: Docker CE 17.09.1 supports only Red Hat Enterprise Linux (RHEL) 7. Therefore, be sure that the operating system node is a RHEL 7 image when you build a virtual system pattern with a Docker container. If a RHEL 6 image is selected, the virtual system pattern deployment fails.

The Docker pattern installs Docker CE 17.09.1. All required dependencies are installed on the RHEL 7.3 image, version 3.0.9.0, which is available with the Cloud Pak System group content (sometimes referred to as default data). If you use a different RHEL 7 image, some of the Docker prerequisites, such as libseccomp package, might not be available. You can still use these images if you have a Red Hat Satellite server that is deployed in the same environment profile as the deployed Docker pattern instance. The Docker pattern tries to install the missing packages by using the Red Hat Satellite server.