Installing Buildkite Agent on Red Hat Enterprise Linux, CentOS, and Amazon Linux

Installation

Start by adding the yum repository for your architecture (if unsure, run uname -m to find your system's architecture).

Buildkite Agent versions come in three release channels:

• Stable: Thoroughly tested, production-ready releases recommended for most users.
• Unstable/Beta: Newer features that are still being tested, may contain bugs that affect stability.
• Experimental: Built directly from the main branch, may be incomplete or have unresolved issues.

The default version of the agent is stable. You can get the beta version by using unstable instead of stable or the experimental version by using experimental instead of stable in the installation commands that follow.

For 64-bit (x86_64):

sudo sh -c 'echo -e "[buildkite-agent]\nname = Buildkite Pty Ltd\nbaseurl = https://yum.buildkite.com/buildkite-agent/stable/x86_64/\nenabled=1\ngpgcheck=0\nrepo_gpgcheck=0\npriority=1" > /etc/yum.repos.d/buildkite-agent.repo'

For 32-bit (i386):

sudo sh -c 'echo -e "[buildkite-agent]\nname = Buildkite Pty Ltd\nbaseurl = https://yum.buildkite.com/buildkite-agent/stable/i386/\nenabled=1\ngpgcheck=0\nrepo_gpgcheck=0\npriority=1" > /etc/yum.repos.d/buildkite-agent.repo'

For ARM 64-bit (aarch64):

sudo sh -c 'echo -e "[buildkite-agent]\nname = Buildkite Pty Ltd\nbaseurl = https://yum.buildkite.com/buildkite-agent/stable/aarch64/\nenabled=1\ngpgcheck=0\nrepo_gpgcheck=0\npriority=1" > /etc/yum.repos.d/buildkite-agent.repo'

Then install the agent:

sudo yum -y install buildkite-agent

Configure your agent token:

sudo sed -i "s/xxx/INSERT-YOUR-AGENT-TOKEN-HERE/g" /etc/buildkite-agent/buildkite-agent.cfg

After the installation, you can start the agent and tail the logs by using the following command:

sudo systemctl enable buildkite-agent && sudo systemctl start buildkite-agent
sudo tail -f /var/log/messages

SSH key configuration

SSH keys should be copied to (or generated into) /var/lib/buildkite-agent/.ssh/. For example, to generate a new private key which you can add to your source code host:

$ sudo su buildkite-agent
$ mkdir -p ~/.ssh && cd ~/.ssh
$ ssh-keygen -t rsa -b 4096 -C "build@myorg.com"

See the Agent SSH keys documentation for more details.

File locations

• Configuration: /etc/buildkite-agent/buildkite-agent.cfg
• Agent Hooks: /etc/buildkite-agent/hooks/
• Builds: /var/buildkite-agent/builds/
• Logs, depending on your system:
  • journalctl -f -u buildkite-agent (systemd)
  • /var/log/buildkite-agent.log (older systems)
• Agent user home: /var/lib/buildkite-agent/
• SSH keys: /var/lib/buildkite-agent/.ssh/

Configuration

The configuration file is located at /etc/buildkite-agent/buildkite-agent.cfg. See the configuration documentation for an explanation of each configuration setting.

Which user the agent runs as

On Red Hat, the Buildkite Agent runs as user buildkite-agent.

Running multiple agents

You can run as many parallel agent workers on the one machine as you wish with the spawn configuration setting, or by passing the --spawn flag.

# Start 5 workers. Each one independently fetches and executes jobs.
spawn=5

Upgrading

sudo yum clean expire-cache && sudo yum update buildkite-agent

Systemd modifications

To override specific directives from the buildkite-agent.service systemd unit file, implement these configurations using the drop-in directory /etc/systemd/system/buildkite-agent.service.d. Within this directory, any files ending with .conf are merged in alphanumeric order and parsed after the main buildkite-agent.service unit file. Therefore, these *.conf files can be used to override or extend the directives of the buildkite-agent.service systemd unit file.

The following .conf file example overrides the operating system user account running the buildkite-agent service, and the environment variable for HOME:

[Service]
# Run the buildite-agent service as a different user:
User=my-service-account
# Change the environment variable for HOME:
Environment=HOME=/opt/my-service-account