Ubuntu 20.04 Image#

The ubuntu2004 is a customized image based on Ubuntu 20.04 LTS optimized for CI/CD. It comes with a set of preinstalled languages, databases, and utility tools commonly used for CI/CD workflows. The image can be paired with any Linux machine type when defining the agent of your pipeline or block.

The ubuntu2004 is a virtual machine (VM) image. The user in the environment, named semaphore, has full sudo access. The image will be updated bi-weekly, on first and third Monday of every month. Updates can be followed on Semaphore Changelog.

The ubuntu2004 VM uses an APT mirror that is in the same data center as Semaphore's build cluster, which means that caching packages will have little effect.

Using the ubuntu2004 OS image in your agent configuration#

To use the ubuntu2004 OS image, define it as the os_image of your agent's machine.

version: 1.0
name: Ubuntu18 Based Pipeline

    type: e1-standard-2
    os_image: ubuntu2004

  - name: "Unit tests"
        - name: Tests
            - make test


The ubuntu2004 comes with two utility tools. One for managing background services and database, and one for managing language versions.

Version control#

Following version control tools are pre-installed:

  • Git (2.x)
  • Git LFS (Git Large File Storage)
  • GitHub CLI (2.x)
  • Mercurial (4.5.x)
  • Svn (1.9.x)

Browsers and Headless Browser Testing#

  • Firefox 78.1
  • geckodriver 0.26.0
  • Google Chrome
  • Chrome_driver
  • Xvfb (X Virtual Framebuffer)
  • Phantomjs 2.1.1

Chrome and Firefox both support headless mode. You shouldn't need to do more than install and use the relevant Selenium library for your language. Refer to the documentation of associated libraries when configuring your project.


Docker toolset is installed and following versions are available:

  • Docker 20.10
  • docker-compose 1.29.2
  • Buildah
  • Podman
  • Skopeo

Cloud CLIs#

  • aws-cli
  • azure-cli
  • eb-cli
  • ecs-cli
  • doctl
  • gcloud
  • kubectl
  • heroku

Network utilities#

  • httpie
  • curl
  • rsync


Erlang and Elixir#

Erlang versions are installed and managed via kerl. Elixir versions are installed with kiex.

  • Erlang: 22.3, 23.3, 24.1 (default)
  • Elixir: 1.9.0, 1.9.1, 1.9.2, 1.9.3, 1.9.4, 1.10.0, 1.10.1, 1.10.2, 1.10.3, 1.10.4, 1.11.0, 1.11.1, 1.11.2, 1.11.3, 1.11.4, 1.12.0, 1.12.1, 1.12.2, 1.12.3 (default)

Additional libraries:

  • rebar3: 3.14.3



  • 1.10.8
  • 1.11.13
  • 1.12.17
  • 1.13.15
  • 1.14.9
  • 1.14.13
  • 1.15.2
  • 1.15.6

Java and JVM languages#

  • Java: 11, 17
  • Scala: 2.12.10
  • Leiningen: 2.9.1 (Clojure)
  • sbt

Additional build tools#

  • Maven: 3.6.3
  • Gradle: 7.3

JavaScript via Node.js#

Node.js versions are managed by nvm. You can install any version you need with nvm install [version]. Installed version:

  • v16.13.0 (set as default)

Additional tools#

  • Yarn: 1.22.15


PHP versions are managed by phpbrew. Installed versions:

  • 7.4.x
  • 8.0.x

The default installed PHP version is 7.4.26.

Additional libraries#

phpunit: 7.5.20


Python versions are installed and managed by virtualenv. Installed versions:

  • 3.8
  • 3.9

Supporting libraries:

  • pypy: 7.3.6
  • pypy3: 7.3.7
  • pip: 21.3
  • venv: 16.0.0


Available versions:

  • 2.6.0 to 2.6.9
  • 2.7.0 to 2.7.5
  • 3.0.0 to 3.0.3
  • jruby-

Installing dependencies with apt package manager#

The Semaphore Ubuntu:20.04 image has most of the popular programming languages, tools and databases preinstalled.

If the dependency you need is not present in the list above, you can install it with the Ubuntu package manager or using an alternative method such as compiling it from the source, or manually downloading binaries.

To install dependecies using the package manager (apt-get) you can use the template command below and add it to your pipeline:

sudo apt-get update
sudo apt-get install -y [your-dependency]

See Also#