Purging the custom kernel does not remove initramfs

[Robert C Jennings]

Purge the kernel and you will be left with the initramfs in /boot and /var/lib/initramfs-tools. This is handled correctly for linux-generic/linux-virtual.

* Launch a bionic/cosmic AWS image
* Purge the kernel
$ sudo apt-get purge --assume-yes '^linux-.*' 'linux-base+' initramfs*

$ ls /boot/
grub initrd.img-4.15.0-1021-aws

$ ls /var/lib/initramfs-tools/
4.15.0-1021-aws

This was seen with Bionic and Cosmic with linux-aws and linux-kvm

Impact: during cloud image builds we remove one kernel and install the optimized kernel like linux-aws. The missing cleanup consumes disk space for images that are meant to be small; it also surfaces a latent bug in initramfs-tools where mkinitramfs will attempt to run to update every initramfs in /var/lib/initramfs-tools/ when it is only half-configured and it falls over. We'll work around this but the kernels should clean up when purged.

[Tiago Stürmer Daitx (tdaitx)]

A few questions:
- Could you please provide the output of the apt-get purge call?
- If update-initramfs is called in it, could you please manually call it with the verbose flag (-v) and attach the output?
- Does this only happen on the half-configured scenario?

I'm moving the status to Incomplete. Please feel free to move it back to New as soon as new information is available.

[Steve Langasek (vorlon)]

On Wed, Sep 19, 2018 at 02:02:36PM -0000, Tiago Stürmer Daitx wrote:
> A few questions:
> - Could you please provide the output of the apt-get purge call?
> - If update-initramfs is called in it, could you please manually call it with the verbose flag (-v) and attach the output?
> - Does this only happen on the half-configured scenario?

I have hypothesized that this is because these custom kernels only recommend
initramfs-tools rather than depending on it, which allows the
initramfs-tools package to be removed before the kernel image package is
removed, and initramfs-tools does not consider itself responsible for
removing the initramfs from disk on package purge.

[Launchpad Janitor (janitor)]

[Expired for linux-aws (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for linux-kvm (Ubuntu) because there has been no activity for 60 days.]