Why k3s is still seeing swap on Debian Bullseye?

Question

I've installed k3s on Debian Bullseye (on M1 Pro through qemu/UTM).

k3s recommend to disable the swap. After reading the answers of the following questions:

• How to safely turn off swap permanently and reclaim the space? (on Debian Jessie)

• Disabling Swap on Debian Permanently

I've :

• Disabled systemd swap service sudo systemctl mask "dev-*.swap"
• Removed the swap partition in /etc/fstab.
• Deleted the swap partition and extend the main partition to regain space
• Set the swapiness to 0 in /etc/sysctl.conf

Now I have:

root@debian:~# systemctl --type swap --all
  UNIT LOAD ACTIVE SUB DESCRIPTION
0 loaded units listed.

root@debian:~# sysctl vm.swappiness
vm.swappiness = 0

root@debian:~# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sr0     11:0    1 1024M  0 rom  
vda    254:0    0   10G  0 disk 
├─vda1 254:1    0  512M  0 part /boot/efi
└─vda2 254:2    0  9.5G  0 part /

root@debian:~# free
               total        used        free      shared  buff/cache   available
Mem:         1000692      705588       34164        1704      260940      221484
Swap:              0           0           0

root@debian:~# swapon -s
root@debian:~#

But when I run k3s check-config, I still have:

- swap: should be disabled

What should I do in order to fully disable the swap in the eyes of k3s?

Answer 1

The swap activation probably happens early in the boot process while the system is still running on initramfs, so after removing the swap configuration items, you should have done a update-initramfs -u.

I also don't see a systemctl stop "dev-*.swap" or swapoff -a anywhere: those would have been the commands to actually disable already-activated swap areas. systemctl mask will certainly prevent the swap units from starting, but it does nothing at all to swap areas that have already been activated. You should ensure any units you are systemctl masking are stopped first.

Answer 2

I restarted the Debian Bullseye VM multiple times but this was not enough. For whatever reasons, I had to stop and restart UTM. After that k3s was seeing that the swap was removed.