Public bug reported:

[Impact]

Our kernel builds are sometimes running out of space on the builders
when we are building multiple flavours. We've seen this with focal
:linux-hwe for amd64 and impish:linux-unstable for arm64. This is in
part because package builds are broken up into a build phase (which
builds the source tree) and a binary phase (which creates the debs).
These are run separately, with the binary phase run under fakeroot to
get correct ownership for files in the package archives, requiring
builds for multiple flavours to be present on disk at the same time.

We have implemented various fixes for this problem over time, and
explored many others which have not worked out. But the size of the
kernel keeps increasing, and now it seems our only remaining option is
to build one flavour and install its files, then remove the flavour
build files before building the next flavour. This means that files are
installed for later package builds during the build phase, requiring
that ownership of these files be fixed up during the binary phase to get
correct ownership in the package archives.

[Test Plan]

Build a full set of kernel packages (inlcuding linux-source and dbgsym
packages, which are generally excluded when not building on builders) at
a given tag, then build another set from the same tag with the packaging
changes applied. Compare the resulting debs to confirm that the set of
produced packages is the same, the file lists within the packages are
the same, and that file ownership and permissions between the packages
is identical.

I have done this testing with the proposed patches with a recent linux-
unstable tag and found no differences with and without the changes.

[Where problems could occur]

Incorrect ownership of files in the package archives is the main
concern. I have tested for this, but it is possible that future upstream
changes could unexpectedly result in files with incorrect ownership.

Reordering of the package build sequence could result in missing files
which should be in packages, or files present in packages which should
be excluded. Some instances of this occurred while developing these
changes and have been fixed. Future updates to upstream or to the
packaging could cause additional issues.

** Affects: linux (Ubuntu)
     Importance: Medium
     Assignee: Seth Forshee (sforshee)
         Status: In Progress

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1930713

Title:
  Kernel package builds running out of space on builders

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1930713/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to