Add `docker-cli` to `ubuntu-slim`

[Domini]

Tool name

docker-cli

Tool license

Apache License 2.0

Add or update?

• Add
• Update

Desired version

latest

Approximate size

6315 kB to download, 29.7 MB installed on trixie-slim

Brief description of tool

While nested virtualization is rarely needed in ubuntu-slim, docker-cli remains essential for tasks like querying registries (e.g., docker manifest inspect).

I switched to ubuntu-slim to save GitHub resources, but it lacks this tool. This forces a bad choice: either waste ~4s runtime installing it manually (adding YAML complexity) or use the resource-heavy ubuntu-latest.

Pre-installing docker-cli in the image would solve this efficiency issue.

URL for tool's homepage

https://mobyproject.org

Provide a basic test case to validate the tool's functionality.

Platforms where you need the tool

• Azure DevOps
• GitHub Actions

Runner images where you need the tool

• Ubuntu 22.04
• Ubuntu 24.04
• Ubuntu Slim
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• macOS 26 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Can this tool be installed during the build?

DEBIAN_FRONTEND=noninteractive apt-get --no-install-recommends --no-install-suggests -y install docker-cli

Tool installation time in runtime

~4s

Are you willing to submit a PR?

No response

[erik-bershel]

Yes, running a container within a container can be challenging, but the command-line functionality itself can make sense for many use cases. We'll consider the implementation from a support and future maintenance perspective and come back with a final solution later.