Curtin fails to deploy image when using an ext2 base filesystem due to swap.img

I think this is a bug in Curtin. I just tried to deploy a CentOS 8 AMD64 image with an ext2 filesystem and I get the same error. One thing I just realized, MAAS doesn't request that a swap file is created in curtin.cfg. When deploying Ubuntu or CentOS with an ext4 base filesystem swap is not created. It seems Curtin automatically tries to enable Swap in some cases when ext2 is used as the base filesystem.

I don't know whether this is a bug in curtin or whatever is generating the config. Curtin tries to add a swapfile by default but it's easy to disable. Subiquity currently disables the swapfile if a swap partition is mounted or if / is on btrfs (subiquity doesn't let you format as ext2). Where should the logic of which filesystems support swapfiles live?

The attached tar files contain the Curtin configuration MAAS is sending. It defines storage but doesn't mention swap at all. MAAS does support configuring swap partitions but that must be done manually by the user.

What's interesting is that if you deploy Ubuntu 20.04 on AMD64 with ext2 swap isn't created. Nor is swap created when you use an ext4 filesystem. Because Curtin is already deciding when to add a swap file I think the logic should live in Curtin. Curtin docs[1] do define a "force" field to "Force the creation of swapfile even if curtin detects it may not work." So it seems there is some logic in Curtin already.

[1] https://curtin.readthedocs.io/en/latest/topics/config.html?highlight=multipath#swap

Ah, you're right. I guess this line here https://git.launchpad.net/curtin/tree/curtin/swap.py#n106 needs an update?

The easiest solution is probably to disallow swap files on ext2, like what is done for ZFS.

Hmm actually I think the fix is to allocate space for swapfiles with dd on ext2 (and maybe ext3 as well?)

This bug is fixed with commit c204635e to curtin on branch master.
To view that commit see the following URL:
https://git.launchpad.net/curtin/commit/?id=c204635e

This bug is believed to be fixed in curtin in version 21.3. If this is still a problem for you, please make a comment and set the state back to New

Thank you.