Version 1.15. This version is no longer supported. For information about how to upgrade to version 1.16, see Upgrade clusters in the latest documentation. For more information about supported and unsupported versions, see the Version history page in the latest documentation.

Configure CentOS

You must configure the base operating system of your node machines to use Distributed Cloud. This page contains the steps you need to take to complete the needed configuration.
For more information about troubleshooting 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 8.2
CentOS 8.3
CentOS 8.4
CentOS 8.5

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

Check for updates:
```
sudo dnf check-update
```
Ensure the output has no errors and includes the last metadata expiration check. For example:
```
# Last metadata expiration check: ...
...
google-cloud-sdk.x86_64 ...
```

Configure or disable firewalld

Firewalld can be configured for use with Google Distributed Cloud or disabled. For information on configuring firewalld, see Configuring firewalld ports on the Network requirements page.

The following instructions disable 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)

Configure Docker 19.03+ on your workstation

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

Set up time synchronization

Time synchronization consists of setting the clocks on your node machines, using a designated external time reference. Time synchronization is important for time-sentive cluster activities, such as event logging and metrics collection. The kernel of your node machine controls the clock in containers that run on the node. To ensure proper time synchronization, install a network time protocol (NTP) service on your machines, using any of the available services: chrony, systemd- timesyncd, ntp, or ntpdate. Run timedatectl to verify that the system clock is synchronized. The output of timedatectl should contain the following status:

System clock synchronized: yes