» RHEL Requirements for Terraform Enterprise

When installing Terraform Enterprise on RedHat Enterprise Linux (RHEL), ensure your OS and Docker configuration meet the following requirements.

» Install Requirements

  • A supported version of RedHat Enterprise Linux.
  • One of the following installations of Docker:
    • Docker CE 17.06 or later. Docker CE can either be pre-installed by the operator or installed via our installation script. If Docker CE is pre-installed by the operator, be sure to pass the no-docker flag to the installation script to prevent it from trying to install Docker CE again.
    • Docker EE 17.06 or later.
    • Docker 1.13.1 installed via the RHEL Extras repository. Details on how to subscribe to the RHEL Extras repository can be found here.
  • Docker configured with the overlay2 storage driver. This is the default storage driver for the latest Docker installations.

» Pinning the Docker Version

To pin the version of Docker and prevent an inadvertent upgrade, follow this guide from RedHat.

» Downgrading the Docker Version

The yum downgrade command can be used to downgrade the version of Docker that is installed.

For example, to downgrade from docker-1.13.1-84.git07f3374.el7.x86_64 to docker-1.13.1-72.git6f36bd4el8.x86_64 stop the Docker service and execute the following.

sudo yum downgrade docker-1.13.1-72.git6f36bd4el7.x86_64 docker-client-1.13.1-72.git6f36bd4el7.x86_64 docker-common-1.13.1-72.git6f36bd4el7.x86_64 docker-rhel-push-plugin-1.13.1-72.git6f36bd4el7.x86_64

Afterwards, restart the Docker service and verify the newly installed version using docker version.

» Mandatory Configuration

If you opt to use Docker 1.13.1 from RHEL extras, then you must make a change to its default configuration to avoid hitting an out of memory bug.

  1. Open /usr/lib/systemd/system/docker.service.
  2. Remove the line that contains --authorization-plugin=rhel-push-plugin.
  3. Run systemctl daemon-reload && systemctl restart docker.
  4. Run docker info 2> /dev/null | grep Authorization to verify that there are no authorization plugins active. If nothing is printed, your installation is properly configured. If anything is printed, please contact support for further assistance.


» Can I use the Docker version in the RHEL Extras repository?

Sure! Just be sure to have at least 1.13.1 and authorization plugins disabled.

» When I run the installer, it allows me to download and install Docker CE on RedHat. Can I use that?

Yes, Docker CE is compatible with Terraform Enterprise. However, it is not directly supported by RedHat.

» Which storage driver should I use?

Please ensure that you are using the overlay2 storage driver.

» Can an installation where docker info says that I’m using devicemapper with a loopback file work?

No. This is an installation that docker provides as sample and is not supported by Terraform Enterprise due to the significant instability in it. Docker themselves do not suggest using this mode.

» How do I know if an installation is in devicemapper loopback mode?

Run the command sudo docker info | grep dev/loop. If there is any output, you’re in devicemapper loopback mode. Docker may also print warning about loopback mode when you run the above command, which is another indicator.