As I stated in the comment, I downgraded the systemd packages to 3.11 to try to get to a working state, but the error persisted after the downgrade.
To get the full picture, these were the updated packages after which kvm stopped to work: root@MGL1-SRV-0006:~# apt list --upgradable Listing... Done libnss-mymachines/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] libnss-systemd/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] libpam-systemd/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] libsystemd0/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] libudev1/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] libudisks2-0/focal-updates 2.8.4-1ubuntu2 amd64 [upgradable from: 2.8.4-1ubuntu1] libvirt-clients/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] libvirt-daemon-driver-qemu/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] libvirt-daemon-driver-storage-rbd/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] libvirt-daemon-system-systemd/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] libvirt-daemon-system/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] libvirt-daemon/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] libvirt0/focal-updates 6.0.0-0ubuntu8.14 amd64 [upgradable from: 6.0.0-0ubuntu8.13] python3-os-vif/focal-updates 2.0.0-0ubuntu2 all [upgradable from: 2.0.0-0ubuntu1] python3-pyroute2/focal-updates 0.5.9-0ubuntu2 all [upgradable from: 0.5.9-0ubuntu1] systemd-container/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] systemd-sysv/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] systemd/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] udev/focal-updates 245.4-4ubuntu3.13 amd64 [upgradable from: 245.4-4ubuntu3.11] udisks2/focal-updates 2.8.4-1ubuntu2 amd64 [upgradable from: 2.8.4-1ubuntu1] -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1943990 Title: After updating systemd packages to 245.4-4ubuntu3.13 and libvirt packages to 6.0.0-0ubuntu8.14, it is no longer possible to start kvm virtual machines Status in systemd package in Ubuntu: Incomplete Bug description: # systemctl status systemd-machined.service ● systemd-machined.service - Virtual Machine and Container Registration Service Loaded: loaded (/lib/systemd/system/systemd-machined.service; static; vendor preset: enabled) Active: inactive (dead) Docs: man:systemd-machined.service(8) https://www.freedesktop.org/wiki/Software/systemd/machined Sep 17 15:40:42 MGL1-SRV-0006 systemd[1]: Dependency failed for Virtual Machine and Container Registration Service. Sep 17 15:40:42 MGL1-SRV-0006 systemd[1]: systemd-machined.service: Job systemd-machined.service/start failed with result 'dependency'. Sep 17 15:42:26 MGL1-SRV-0006 systemd[1]: Dependency failed for Virtual Machine and Container Registration Service. Sep 17 15:42:26 MGL1-SRV-0006 systemd[1]: systemd-machined.service: Job systemd-machined.service/start failed with result 'dependency'. Sep 17 16:02:55 MGL1-SRV-0006 systemd[1]: Dependency failed for Virtual Machine and Container Registration Service. Sep 17 16:02:55 MGL1-SRV-0006 systemd[1]: systemd-machined.service: Job systemd-machined.service/start failed with result 'dependency'. Sep 17 16:04:39 MGL1-SRV-0006 systemd[1]: Dependency failed for Virtual Machine and Container Registration Service. Sep 17 16:04:39 MGL1-SRV-0006 systemd[1]: systemd-machined.service: Job systemd-machined.service/start failed with result 'dependency'. Trying to start a virtual machine from openstack, it defines the machine, but is not able to execute it. I used to have libvirt apparmor errors, but disabling libvirt in apparmor didn't solve the problem: [ 27.785713] audit: type=1400 audit(1631888214.441:67): apparmor="DENIED" operation="capable" profile="libvirtd" pid=4817 comm="libvirtd" capability=17 capname="sys_rawio" ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: systemd-container 245.4-4ubuntu3.11 ProcVersionSignature: Ubuntu 5.11.0-34.36~20.04.1-generic 5.11.22 Uname: Linux 5.11.0-34-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.20 Architecture: amd64 CasperMD5CheckResult: skip Date: Fri Sep 17 16:23:39 2021 SourcePackage: systemd UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1943990/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp