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:

1. 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 
    
   

2. 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

1. Set SELinux to permissive:

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

2. After rebooting, verify SELinux is set to permissive:

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

Disabling firewalld

1. Disable firewalld :

    sudo systemctl stop firewalld
   sudo systemctl disable firewalld 
   

2. 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:

1. 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 
   

2. Remove podman-manpages

    sudo dnf remove podman-manpages 
   

3. 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 
    
   

4. Verify you are now running version 19.03+:

    sudo docker version 
   

5. 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 
   

6. 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