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Runners

How and why to use Semaphore runners
Runners enable running tasks on a separate server from Ansible Semaphore.
Semaphore runners operate on the same principle as GitLab or GitHub Actions runners:
  • You launch a runner on a separate server, specifying the Semaphore server's address and an authentication token.
  • The runner connects to Semaphore and signals its readiness to accept tasks.
  • When a new task appears, Semaphore provides all the necessary information to the runner, which, in turn, clones the repository and runs Ansible.
  • The runner sends the task execution results back to Semaphore.
For end users, working with Semaphore with or without runners appears the same.
Using runners offers the following advantages:
  • Executing tasks more securely. For instance, a runner can be located within a closed subnet or isolated docker container.
  • Distributing the workload across multiple servers. You can start multiple runners, and tasks will be randomly distributed among them.

Setup

The runner comes as part of Semaphore and is launched with the following command:
semaphore runner --config ./config.json
The configuration file should contain a runner section with the following parameters:
{
"runner": {
"registration_token": "***",
"config_file": "path/to/the/file/where/runner/saves/service/information",
"api_url": "http://<semaphore_host>:<semaphore_port>/api",
"max_parallel_tasks": 10
}
}
To enable Semaphore to work with runners, the following parameters should be present in its configuration file:
{
"use_remote_runner": true,
"runner_registration_token": "***"
}