Accelerate the build: Drop unused checksum generation

[Robert C Jennings]

[Impact]

 * Image builds take time
 * Some of the time is spent computing checksums
 * Those checksums are never used
 * Time and energy is wasted
 * build/(md5|sha256)sum.txt is not used by livecd-rootfs and not exposed by launchpad-buildd

[Test Case]

 * Build images
 * Disable checksums
 * Build images
 * Ensure image deliverables are unchanged

[Regression Potential]

 * Someone was using the checksums outside of launchpad-buildd; because launchpad-buildd doesn't present those artifacts
 * The checksums are included beside the squashfs in live-build ISOs but none of our projects use live-build to build ISOs.

[Robert C Jennings (rcj)]

This change was made during the cosmic development cycle in r1685[1].

[1] https://bazaar.launchpad.net/~ubuntu-core-dev/livecd-rootfs/trunk/revision/1686

[Robert C Jennings (rcj)]

Can I get this targeted for bionic and xenial?

[Brian Murray (brian-murray)]

This not being fixed in bionic, or at least being in -proposed, is blocking the xenial livecd-rootfs SRU from proceeding.

[Brian Murray (brian-murray)]

Hello Robert, or anyone else affected,

Accepted livecd-rootfs into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/livecd-rootfs/2.408.41 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Brian Murray (brian-murray)]

Hello Robert, or anyone else affected,

Accepted livecd-rootfs into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/livecd-rootfs/2.525.10 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Steve Langasek (vorlon)]

Successful bionic image builds showing livecd-rootfs 2.525.10 from -proposed in use:

https://launchpad.net/~ubuntu-cdimage/+livefs/ubuntu/bionic/ubuntu-server-live/+build/151051
https://launchpad.net/~ubuntu-cdimage/+livefs/ubuntu/bionic/ubuntu-server/+build/151041
https://launchpad.net/~ubuntu-cdimage/+livefs/ubuntu/bionic/ubuntu/+build/151054

No discernable improvement to the build times, but that's ok.

[Launchpad Janitor (janitor)]

This bug was fixed in the package livecd-rootfs - 2.525.10

---------------
livecd-rootfs (2.525.10) bionic; urgency=medium

  [ Cody Shepherd ]
  * Include grub efi packages in manifests for uefi images.
    (LP: #1805190)

  [ Robert C Jennings ]
  * Disable checksum generation. (LP: #1799773)

  [Steve Langasek]
  * Fix Vcs-Bzr link.

 -- Steve Langasek <email address hidden> Mon, 26 Nov 2018 12:55:11 -0800

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for livecd-rootfs has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Robert C Jennings (rcj)]

I have verified the -proposed package in xenial by building the ubuntu-cpc project. Images were unchanged but times were not decreased significantly (though I'm building on hardware with lots of memory and fast disk). Marking as verification-done.

[Launchpad Janitor (janitor)]

This bug was fixed in the package livecd-rootfs - 2.408.41

---------------
livecd-rootfs (2.408.41) xenial; urgency=medium

  * Disable checksum generation (LP: #1799773)

livecd-rootfs (2.408.40) xenial; urgency=medium

  [ Cody Shepherd ]
  * Increasing modularity in relocation of /etc/resolv.conf to enable users
    of live-build/functions to manipulate /etc/resolv.conf in a more
    granular and future-proof way. LP: #1801134.

livecd-rootfs (2.408.39) xenial; urgency=medium

  * Backport support for building ubuntu-core images with ubuntu-image (using
    IMAGEFORMAT=ubuntu-image).
  * Decide what model assertion series to fetch depending on the suite. Use 16
    for xenial and 18 for other series (bionic+). This enables core18 image
    builds (LP: #1799736).

 -- Robert C Jennings <email address hidden> Fri, 16 Nov 2018 08:37:57 -0800