Configuring CentOS

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 requirements, see the troubleshooting guides .

Before you begin

Ensure you are using a supported version of your operating system. Anthos on bare metal supports the following versions for CentOS:

• CentOS 8.1
• CentOS 8.2

Ensure you have root access to the machines you are configuring.Validate Package manager with the following steps:

1. Check for updates:

    sudo  
   dnf  
   check-update 
   

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

     # 
   Last metadata expiration check: ...
   ...
   google-cloud-sdk.x86_64 ... 
   

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  
    # persistent - requires reboot 
    
   

2. 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. 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 
   

3. Verify you are now running version 19.03+:

    sudo  
   docker  
   version 
   

4. 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 
   

Setting up time synchronization

To ensure proper time synchronization, install an NTP service on your machines using any of the available services: chrony , systemd-timesyncd , ntp, or ntpdate. Run timedatectl to verify the system clock is synchronized. The output of timedatectl should contain the following status:

 System clock synchronized: yes