GitHub Actions runners

Run your repository’s builds and tests on Celesto computers, and keep your workflow results and logs in GitHub Actions. Celesto starts a fresh computer for each job and deletes it when the job finishes. Use the Docker guide for image builds and database services, or benchmarking to compare your workflow’s speed and cost. Review security and permissions before running contributor workflows. Use dependency caching to reuse downloads between jobs.

Quickstart

You need a GitHub account that administers the repositories you select, a Celesto workspace where you are an admin, and usable workspace credit. A workspace owner can start the eligible, card-free $5 Micro trial.

Install and connect

Install the Celesto CI GitHub App and select the repositories you want to use. Follow the redirect to Celesto, sign in or create an account, and connect the installation to the workspace that will pay for its jobs.Start the eligible trial or add workspace credit before running a job. Installing the App alone does not finish setup. If the trial is blocked by an existing computer, follow trial recovery.

Add a workflow

Save this complete example as .github/workflows/celesto-ci.yml in a selected repository:

.github/workflows/celesto-ci.yml

name: Celesto CI
on: [push, workflow_dispatch]
jobs:
  verify:
    runs-on: [self-hosted, celesto-micro]
    timeout-minutes: 90
    steps:
      - uses: actions/checkout@v4
      - name: Check the runner
        run: |
          uname -m
          python --version
          node --version
          git --version
          echo "Running on Celesto"

For an existing compatible workflow, change its runs-on line and keep your steps. Check the tools and limits below before moving a workflow from ubuntu-latest.

Push and verify

Commit and push the workflow. Open the repository’s Actions tab and select Celesto CI. The Check the runner step should print x86_64, tool versions, and Running on Celesto, and the job should finish with a green check.The separate Celesto runner setup check reports computer creation and runner assignment. GitHub’s native Actions result tells you whether your steps passed. Celesto deletes the job computer afterward.

Sizes and prices

Use runs-on: [self-hosted, celesto-SIZE] with exactly one label from this table. All sizes use Ubuntu 24.04 Linux x64. Prices are in USD; minute rates are rounded for display.

Size	Workflow label	vCPU	RAM	Disk	Per minute	Per hour
Micro	`celesto-micro`	1	2 GB	20 GB	$0.00025	$0.015
Small	`celesto-small`	1	4 GB	25 GB	$0.00033333	$0.020
Standard	`celesto-standard`	2	4 GB	30 GB	$0.0005	$0.030
Memory	`celesto-memory`	2	8 GB	40 GB	$0.00066667	$0.040
Large	`celesto-large`	4	16 GB	60 GB	$0.00133333	$0.080
XL	`celesto-xl`	8	32 GB	100 GB	$0.00266667	$0.160

For example, runs-on: [self-hosted, celesto-memory] selects 2 vCPU and 8 GB RAM. The current workspace billing catalog is authoritative; setup reads the current specs and rates. Celesto charges workspace credit for the computer’s runtime, including preparation, job execution, and cleanup. The one-time $5 trial covers up to 20,000 Micro runtime minutes at the listed rate, expires after 30 days, and is shared with other sandbox usage. Other sizes require eligible workspace credit; some promotional credit is restricted to Micro or Small.

What is preinstalled?

The CI image includes these tools:

Area	Included tools
Runner	Official GitHub Actions runner and its ICU dependency
Python	Python 3.12, pip, uv, uvx
JavaScript	Node.js 24, npm, npx, pnpm
Source control	Git, OpenSSH client
Containers	Docker Engine, Buildx, and Compose v2
Build tools	C/C++ compiler toolchain, make, pkg-config, OpenSSL development libraries
Utilities	Bash, curl, jq, ripgrep (`rg`), fd, SQLite, zip/unzip, tar, gzip, xz
Coding agents	Pi coding agent

This is Celesto’s CI image, rather than GitHub’s hosted runner image. Install your project dependencies and any additional tools in workflow steps. Pin the versions your project needs with compatible setup actions such as actions/setup-node or actions/setup-python.

Limits and compatibility

Operating system: Ubuntu Linux x64. Windows, macOS, and ARM jobs need another runner.
Actions and containers: Shell steps, compatible JavaScript actions, Docker image builds, Compose, and native PostgreSQL services: have been exercised on Celesto CI. See Docker support and known limits for tested examples and configurations to validate before migration.
Runtime: Job computers have a two-hour safety limit. Set timeout-minutes below 120 to leave room for runner preparation and cleanup; the quickstart uses 90.
Concurrency: Available capacity, workspace sandbox limits, and usable credit govern admission. The Micro trial allows one retained sandbox at a time, so an existing sandbox can block a CI runner.
Local files: Each computer serves one job and is deleted afterward. Use GitHub Actions artifacts or compatible caching steps to keep results or dependencies between jobs.
Repository access: Select every repository that uses Celesto labels in the App installation. One installation connects to one Celesto workspace. Organization runners use a Celesto runner group restricted to the selected repositories.
Labels: Use exactly one Celesto size label. Unknown or multiple Celesto labels fail setup before a computer starts. Existing celesto-cloud and celesto-cloud-micro labels select Micro; the existing Standard, Large, and XL labels remain supported.
Network: Jobs need outbound access to GitHub and to the services used by your workflow.

If a job stays queued

Use Troubleshooting for cause-specific steps covering retained computers, credit, permissions, and capacity. Open the Celesto runner setup check on the commit. Follow its link to finish connecting the installation, resolve GitHub permissions, or add credit to the linked workspace. Workspace owners manage trial activation and funding. After fixing setup or credit, cancel the old run and rerun it in GitHub. Adding credit does not automatically restart a previously blocked job. If setup reports another failure, use its details when contacting support. To check your own build’s migration, run one real workflow on Celesto and compare its duration and outcome with your existing runner. Different CPU and RAM sizes can change runtime, so a lower per-minute rate alone does not determine the completed-job bill.

Get started

Run your workflows

Measure performance

Manage CI

GitHub Actions runners

Quickstart

Sizes and prices

What is preinstalled?

Limits and compatibility

If a job stays queued

​Quickstart

​Sizes and prices

​What is preinstalled?

​Limits and compatibility

​If a job stays queued

Quickstart

Sizes and prices

What is preinstalled?

Limits and compatibility

If a job stays queued