Version 1.6. This version is no longer supported. For information about how to upgrade to version 1.7, see Upgrading Anthos on bare metal in the 1.7 documentation. For more information about supported and unsupported versions, see the Version history page in the latest documentation.

Configuring RHEL

You must configure the base operating system of your node machines to use Google Distributed Cloud. This page contains the steps you need to take to complete the needed configuration. For more information about troubleshooting Google Distributed Cloud, see the troubleshooting guides.

Before you begin

Ensure you are using a supported version of your operating system. Google Distributed Cloud supports the following versions for RHEL:

RHEL 8.1
RHEL 8.2

Ensure you have root access to the machines you are configuring, and your RedHat username and password.
Validate Package manager with the following steps:

If you haven't registered your operating system, register with RedHat using your username and password to download updates:
```
sudo subscription-manager register
sudo subscription-manager refresh
sudo subscription-manager attach --auto
```
Check for updates:
```
sudo dnf check-update
```

Ensure the output has no errors and the last metadata expiration check, for example:

  Updating Subscription Management repositories.
  ...
  # Last metadata expiration check: ...
  ...

Setting SELinux to `permissive`

Set SELinux to permissive:

sudo setenforce 0 # temporary
sudo sed -i 's/SELINUX=enforcing/SELINUX=permissive/g' /etc/selinux/config

After rebooting, verify SELinux is set to permissive:

sudo sestatus | grep "Current mode"
# Output
# Current mode: permissive

Disabling `firewalld`

Disable firewalld:

sudo systemctl stop firewalld
sudo systemctl disable firewalld

Check the status of firewalld to ensure it is disabled:

sudo systemctl status firewalld | grep "Active"
# Output
# Active: inactive (dead)

Configuring Docker 19.03+ on your workstation

Google Distributed Cloud helps you install Docker on your bare metal machines in the following scenarios:

If your bare metal machines don't have Docker installed, bmctl installs 19.03.13 or later.
If your bare metal machines have Docker 19.03.5 or earlier installed, bmctl upgrades Docker to version 19.03.13 or later.

Follow these steps to manually install Docker:

Remove any previous Docker version:

sudo dnf remove docker \
  docker-client \
  docker-client-latest \
  docker-common \
  docker-latest \
  docker-latest-logrotate \
  docker-logrotate \
  docker-engine

Remove podman-manpages
```
sudo dnf remove podman-manpages
```

Install Docker 19.03+:

sudo dnf install -y yum-utils
sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
sudo dnf install -y docker-ce docker-ce-cli containerd.io
sudo systemctl start docker

Verify you are now running version 19.03+:
```
sudo docker version
```

Compare your output with the following example to ensure the Client and Server versions are 19.03+ :

 Client: Docker Engine - Community
 Version:           19.03.13
 ...
 Server: Docker Engine - Community
  Engine:
  Version:          19.03.13

Verify Docker runs:

docker run hello-world

You should see something similar to this:

Hello from Docker!
This message shows that your installation appears to be working correctly.

Best Practices

To simplify installation, we recommend that you configure RHEL using a minimal installation with headless management. Also, be sure to enable your network connection and either use the default DHCP or provide a valid, static IP address and network information. Ensure the machine can connect to the required external resources, such as cloud.google.com.

If Docker fails to run, check that the Docker daemon is running with the following command:

sudo systemctl start docker