Possible reasons for having this kind of units are:
• A unit may be statically enabled by being symlinked from another unit's
  .wants/ or .requires/ directory.
• A unit's purpose may be to act as a helper for some other unit which has
  a requirement dependency on it.
• A unit may be started when needed via activation (socket, path, timer,
  D-Bus, udev, scripted systemctl call, ...).
• In case of template units, the unit is meant to be enabled with some
  instance name specified.

A dependency job for qemu-guest-agent.service failed. See 'journalctl -xe' for details.
root@kasm:/home/kasm#
root@kasm:/home/kasm# journalctl -xe
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit rpc_pipefs.target has finished successfully.
░░
░░ The job identifier is 4188.
May 15 16:31:57 kasm systemd[1]: Condition check resulted in RPC security service for NFS client and server being skipped.
░░ Subject: A start job for unit rpc-gssd.service has finished successfully
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit rpc-gssd.service has finished successfully.
░░
░░ The job identifier is 4187.
May 15 16:31:57 kasm systemd[1]: Reached target NFS client services.
░░ Subject: A start job for unit nfs-client.target has finished successfully
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit nfs-client.target has finished successfully.
░░
░░ The job identifier is 4183.
May 15 16:32:12 kasm systemd[1]: Reloading.
May 15 16:32:12 kasm systemd[1]: Configuration file /run/systemd/system/netplan-ovs-cleanup.service is marked world-inaccessible. This has no effect as configuration data i>
May 15 16:32:12 kasm systemd[1]: /lib/systemd/system/snapd.service:23: Unknown key name 'RestartMode' in section 'Service', ignoring.
May 15 16:32:12 kasm systemd[1]: Reloading.
May 15 16:32:12 kasm systemd[1]: Configuration file /run/systemd/system/netplan-ovs-cleanup.service is marked world-inaccessible. This has no effect as configuration data i>
May 15 16:32:12 kasm systemd[1]: /lib/systemd/system/snapd.service:23: Unknown key name 'RestartMode' in section 'Service', ignoring.
May 15 16:32:12 kasm systemd[1]: Reloading.
May 15 16:32:13 kasm systemd[1]: Configuration file /run/systemd/system/netplan-ovs-cleanup.service is marked world-inaccessible. This has no effect as configuration data i>
May 15 16:32:13 kasm systemd[1]: /lib/systemd/system/snapd.service:23: Unknown key name 'RestartMode' in section 'Service', ignoring.
May 15 16:33:43 kasm systemd[1]: dev-virtio\x2dports-org.qemu.guest_agent.0.device: Job dev-virtio\x2dports-org.qemu.guest_agent.0.device/start timed out.
May 15 16:33:43 kasm systemd[1]: Timed out waiting for device /dev/virtio-ports/org.qemu.guest_agent.0.
░░ Subject: A start job for unit dev-virtio\x2dports-org.qemu.guest_agent.0.device has failed
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit dev-virtio\x2dports-org.qemu.guest_agent.0.device has finished with a failure.
░░
░░ The job identifier is 4296 and the job result is timeout.
May 15 16:33:43 kasm systemd[1]: Dependency failed for QEMU Guest Agent.
░░ Subject: A start job for unit qemu-guest-agent.service has failed
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit qemu-guest-agent.service has finished with a failure.
░░
░░ The job identifier is 4205 and the job result is dependency.
May 15 16:33:43 kasm systemd[1]: qemu-guest-agent.service: Job qemu-guest-agent.service/start failed with result 'dependency'.
May 15 16:33:43 kasm systemd[1]: dev-virtio\x2dports-org.qemu.guest_agent.0.device: Job dev-virtio\x2dports-org.qemu.guest_agent.0.device/start failed with result 'timeout'.
lines 3345-3393/3393 (END)