apt-get update and upgrade question on Ubuntu 18

cryptsetup: WARNING: failed to detect canonical device of /dev/sda
cryptsetup: WARNING: could not determine root device from /etc/fstab

Cryptsetup is a package that is included within dependencies in ubuntu-server, and it is looking specifically for UUIDs for the drives which Linode does not use as a part of its infrastructure. Linode instead utilizes the /dev/sd* naming convention for the drives as the specific UUID can change.

Cryptsetup is a package that will generally only be used when using disk encryption. These warnings are safe to ignore.

Good to know that it’s a Linode naming convention and not a system error. First time I had seen it on a Ubuntu server.

I fixed these issues with these steps on an 18.04LTS clean install:

If you are using crypt this will not work for you. Check your /etc/fstab

sudo apt-get remove cryptsetup  
sudo update-grub
sudo grub-install /dev/<your_device_id>

For the second issue I rewrote my /etc/fstab using blkids.

sudo blkid

UUID=<Your UUID>       /       ext4    noatime,commit=600,defaults,errors=remount-ro   0       1

UUID=<Your UUID>       none    swap    sw,discard      0       0

Also you will need to update /etc/initramfs-tools/conf.d/resume
On a clean install I needed to create the file resume

RESUME=UUID=<Your UUID>

Now rebuild your initramfs

sudo update-initramfs -u -k all

Hopefully no typos reboot

sudo reboot

I no longer see those issues, hope this helps, as usual YMMV.

I've had the following errors upon running apt update/upgrade on an ubuntu 20.04.1 server with the latest linode-supplied kernel. This is the closest article I found here to the error messages I've encountered, and I'm curious if the errors I'm seeing are related and hopefully just something that can be ignored:

cryptsetup: ERROR: Couldn't resolve device /dev/root
cryptsetup: WARNING: Couldn't determine root device
I: The initramfs will attempt to resume from /dev/sdb
I: (UUID=4xxxxx-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx)
I: Set the RESUME variable to override this.

I'm not running an encrypted drive, basically just a vanilla lamp with a bunch of vhosts running wordpress and sending contact form mail with postfix. The only thing I can think of that would be related to encryption would be the ssl certs for the various sites, but I don't think this warning has anything to do with that.

Ok to ignore these errors, or something that should be fixed?

I'm having the same issue as the above. The answer from Linode staff is over 2 years old. Is there any recent news on this problem?

See my post of today: https://www.linode.com/community/questions/21805/what-are-these-errors-on-apt-upgrade