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• Launchpad Entry: https://blueprints.launchpad.net/ubuntu-arm/+spec/arm-m-derived-archive-rebuild

• Created:

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• Packages affected:

Summary

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Release Note

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Design

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Implementation

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UI Changes

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Code Changes

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Migration

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Unresolved issues

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BoF agenda and discussion

Two ways to do rebuilds:

• Launchpad
• Some way involving a cluster managed by a friendly debian guy

Problems:

• rebuild tests compete with ppa builds
  • builder hardware, pretty good though
  • soyuz scaling issues
    • process-upload serialization (should be fixed soon)
• would like to do this for ARM
  • cross compiling will not work
  • hardware is slow (OO.org takes ~2 days)
  • qemu on even very fast hardware is too slow
  • the qemu-with-a-cross-compiler underneath approach has legs, but isn't ready yet

Use cases for rebuilds:

• verifying the tool chain works
  • lucid all builds with its own toolchain
  • how much does the new version of gcc break?
• we want to rebuild the archive with a new tool chain
  • here we keep the results
  • can be because of optimizations, or a bad compiler flag in previous builds
  • needs something like a binNMU if the results go back into the same archive
  • important to be able to measure the differences

"scorched earth" rebuilds to do with build dependency loops -- session later in the week

The context here is doing rebuilds for Launchpad-managed archives.

Iterated rebuids are useful.

Some part of the process involves running a script on a DC machine that takes an hour -- difficult to expose through Launchpad.

Diskless archives?

The variance of ARM architecture leads towards the requirement of assigning builds to particular builders. Builder pools are related, but existing spec does not cover this. In general, there is a need to store more data about buildds.

Something about checking if a build uses swap, and general performance monitoring of builds.

We could always build into a derived archive, and possibly copy back into the source archives.

ACTIONS

• implement binNMUs in Launchpad
• API exposure for copy-archive in Launchpad
• implementing derived archives would help too

CategorySpec