2b4324af9b
Update both the variables that dictate this and the documents that explain our GCC/glibc policies. These should ease a future migration to a newer GCC version.
43 lines
2.5 KiB
Markdown
43 lines
2.5 KiB
Markdown
---
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last_review_date: "2025-03-28"
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---
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# Linux CI in `homebrew/core`
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We currently use Ubuntu 22.04 for bottling in `homebrew/core`.
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## Ubuntu vs. other Linux distributions
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As of 2022, around 77% of our users are using Ubuntu. This is the reason why we have chosen this distribution for our base CI image.
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We have successfully used Ubuntu for CI since version 14.04.
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The Ubuntu LTS versions are supported for 5 years. A new LTS version is released every 2 years.
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Our bottles are compatible with other distributions like Debian/CentOS, even when compiled on Ubuntu.
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## Past and next versions
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We have moved our CI to Ubuntu 22.04
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Moving from Ubuntu 16.04 to Ubuntu 22.04 (and thus skipping version 18.04 and 20.04) took longer than expected.
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We plan to proceed with regular updates from 2022 onwards. We aim to use the oldest supported Ubuntu LTS version for our CI that provides the GCC version we need.
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| Distribution | Glibc | GCC | LTS standard security maintenance |
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|---|---|---|---|
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| Ubuntu 14.04 | 2.19 | 4 | From 2014 to 2017 |
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| Ubuntu 16.04 | 2.23 | 5 | From 2017 to 2022 |
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| Ubuntu 20.04 | 2.31 | 5 | From 2020 to 2025 |
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| Ubuntu 22.04 | 2.35 | 11 (provides 12) | From 2022 to 2027 |
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| Ubuntu 24.04 | 2.39 | 13 | From 2024 to 2029 |
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| Ubuntu 26.04 | ? | ? | ? |
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[Source](https://ubuntu.com/about/release-cycle)
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## Why upgrade to a newer version?
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Homebrew is a rolling-release package manager. We try to ship the newest things as quickly as possible, on macOS and Linux.
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When a formula needs a newer GCC because our host GCC in CI is too old, we needed to make that formula depend on a newer Homebrew GCC. All C++ dependents of that formula immediately acquire a dependency on Homebrew GCC as well. While we have taken the steps to make sure this no longer holds up GCC updates, it still creates a maintenance burden. This problem is more likely for formula which are very actively maintained and try to use newer features of C++. We decided that we shouldn't have a maintenance burden for formulae which are doing the right thing by staying up to date. It makes a lot of sense for Homebrew maintainers to submit upstream fixes when formulae are not working with newer compilers. It makes a lot less sense for Homebrew maintainers to submit fixes because our host compiler is too old.
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Note that `glibc` will need to be installed for more users as their `glibc` version will often be too old. This is not as smooth as using a newer GCC as we don't test this configuration in CI. This is why we want to balance the newest GCC with a more conservative `glibc`.
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