Freedom251 › Continuous Integration Software
Ambient CI
What Ambient CI is
Ambient CI is a free, open-source command-line tool for running software builds and automated tests on Linux or self-hosted infrastructure. It processes source files into artifacts while isolating project code in QEMU virtual machines. Plans use pre-plan, plan and post-plan actions, each in a fresh ephemeral VM. The central plan has no network access; vetted pre-plan actions can download dependencies, while post-plan actions can access the network and publish outputs through rsync or dput. Configured secret files are copied only to the post-plan VM. Ambient preserves cache and artifact directories between runs and supports configurable limits for CPU, memory, disk, runtime, output, and cache or artifact sizes. Documented actions include Rust checks and builds, Debian packages, shell scripts and custom actions, with dependency downloads for Rust, Debian, npm, Python and Go. Build output is captured in run logs. YAML files define projects and configuration, and installation instructions point to INSTALL.md. Ambient has no hosted option and is described as alpha software.
Who it suits
It suits Linux users and teams wanting self-hosted, locally run CI with network-isolated build plans. Developers should be comfortable with command-line tools, YAML configuration and alpha software.
What it does well
- Free and licensed under AGPLv3 or later
- Build plan runs without network access
- Fresh ephemeral VM for each phase
- Configurable resource, cache and artifact limits
- Supports Rust, Debian, shell and custom actions
What to know first
- Alpha software may change inconveniently
- No hosted option
- Build logs may need post-processing
- GitHub and GitLab integration is listed as a project want
Verdict
Ambient CI focuses on self-hosted builds with strict VM isolation and controlled network access. Its alpha status and command-line setup matter for teams seeking a settled hosted service.
Facts from Ambient CI's own pages
- Build actions
- The guide documents actions for Rust formatting, linting, dependency checks, documentation, builds and tests, plus Debian package builds. · doc.liw.fi, 11 Oct 2026
- Build phases
- CI plans can have pre-plan, plan, and post-plan actions, each running in fresh ephemeral virtual machines. · doc.liw.fi, 11 Oct 2026
- Caching and artifacts
- Ambient preserves cache and artifact directories between runs, with configurable maximum sizes. · doc.liw.fi, 11 Oct 2026
- Dependency downloads
- Vetted pre-plan actions can download dependencies before the network-isolated plan runs. · doc.liw.fi, 11 Oct 2026
- Dependency support
- Documented pre-plan actions download dependencies for Rust, Debian, npm, Python, and Go projects. · doc.liw.fi, 11 Oct 2026
- Execution
- CI plans support pre-plan, plan, and post-plan actions, each run in a fresh, ephemeral virtual machine. · doc.liw.fi, 11 Oct 2026
- Git hosting
- Integration with major Git hosting platforms such as GitHub and GitLab is listed as a project want, rather than a current feature. · ambient.liw.fi, 11 Oct 2026
- How it runs
- Ambient is a command line tool for running CI locally, with jobs executed in QEMU virtual machines. · ambient.liw.fi, 11 Oct 2026
- How it works
- Ambient processes source files into artifacts and can optionally deliver or deploy them. · ambient.liw.fi, 11 Oct 2026
- Installation and configuration
- The user guide directs users to the source tree's INSTALL.md for installation and documents YAML project and configuration files. · doc.liw.fi, 11 Oct 2026
- Isolation
- The build VM has no network access, and Ambient sets resource limits for the VM. · ambient.liw.fi, 11 Oct 2026
- License
- Ambient CI is licensed under the GNU Affero General Public License version 3 or any later version. · ambient.liw.fi, 11 Oct 2026
- Logs
- Ambient captures build output as a run log, which may require post-processing to be useful to developers. · ambient.liw.fi, 11 Oct 2026
- Maintainer
- The user guide is attributed to Lars Wirzenius, and the contact page identifies him as the main Ambient developer. · ambient.liw.fi, 11 Oct 2026
- Maturity
- The project describes Ambient as alpha software that is not feature complete and may change in inconvenient ways. · ambient.liw.fi, 11 Oct 2026
- Network isolation
- The actual build plan runs in a virtual machine with no network access; pre-plan and post-plan actions can access the network. · doc.liw.fi, 11 Oct 2026
- Outputs
- Post-plan actions include options to publish artifacts using rsync or dput. · doc.liw.fi, 11 Oct 2026
- Publishing integrations
- Post-plan actions include rsync and dput options for delivering artifacts. · doc.liw.fi, 11 Oct 2026
- Purpose
- Ambient CI automates builds and tests while isolating project code in a virtual machine without network access. · ambient.liw.fi, 11 Oct 2026
- Resource limits
- Users can configure virtual machine CPU and memory, cache and artifact size limits, and the security page describes limits on disk, CPU, memory, runtime, and output. · ambient.liw.fi, 11 Oct 2026
- Secret handling
- Configured secret files are copied only to the post-plan virtual machine and are not exposed to pre-plan or plan actions. · doc.liw.fi, 11 Oct 2026
- Secrets
- Configured secret files are copied only to the post-plan VM and are not exposed to pre-plan or plan actions. · doc.liw.fi, 11 Oct 2026
- Support
- The project recommends its issue tracker for reporting problems and also lists a fediverse contact for its main developer. · ambient.liw.fi, 11 Oct 2026
- Supported build actions
- Documented actions include Rust checks and builds, Debian package building, shell scripts, and custom actions. · doc.liw.fi, 11 Oct 2026
Where Ambient CI stands on Freedom251
- Continuous Integration Software#50 of 58