On Tue, Aug 9, 2022 at 11:10 AM Chris Murphy lists@colorremedies.com wrote:

cc: cloud@, server@ fpo

Hi,

When troubleshooting early boot issues with a console, e.g. virsh console, or the virt-manager console, or even a server's remote management console providing a kind of virtual serial console... the boot scroll is completely wiped. This is a new behavior in the last, I'm not sure, 6-12 months? Everything before about 3 seconds is cleared as if the console reset command was used, as in it wipes my local scrollback.

I captured this with the script command, and when I cat this 76K file, it even wipes the local console again. So there is some kind of control character that's ordering my local console to do this. The file itself contains the full kernel messages. I just can't cat it. I have to open it in a text editor that ignores this embedded console reset command.

With the help of @glb, we discovered that this is almost certainly Plymouth. When I boot with parameter plymouth.enable=0 the problem doesn't happen. And hence the higher level question if we really even need Plymouth in Server or Cloud editions?

I suppose ideally we'd track down the problem and fix plymouth, so that existing installations get fixed. Whereas if we remove plymouth, we have to ponder whether and how to remove plymouth from existing installations. Unless we flat out aren't using it at all.

Any ideas?

Plymouth is in the @core group in fedora-comps, so pretty much everything gets it. https://pagure.io/fedora-comps/blob/main/f/comps-f37.xml.in#_635

Plymouth is used to provide the interface for decrypting disks and presenting information about software/firmware updates, so I'd be loath to remove it.

That said, it should all be captured in systemd journal logs though.