Comment 2 for bug 1866149

This is causing LXD VMs (Focal, possibly others) to boot in "degraded" state, see [1]. The underlying cause is:

root@paride-f-delme:~# systemctl status systemd-sysctl.service
● systemd-sysctl.service - Apply Kernel Variables
     Loaded: loaded (/lib/systemd/system/systemd-sysctl.service; static; vendor preset: enabled)
     Active: failed (Result: exit-code) since Fri 2020-11-06 16:43:35 UTC; 14min ago
       Docs: man:systemd-sysctl.service(8)
             man:sysctl.d(5)
   Main PID: 301 (code=exited, status=1/FAILURE)

root@paride-f-delme:~# /lib/systemd/systemd-sysctl
Couldn't write '176' to 'kernel/sysrq', ignoring: No such file or directory
Not setting net/ipv4/conf/all/promote_secondaries (explicit setting exists).
Not setting net/ipv4/conf/default/promote_secondaries (explicit setting exists).
Couldn't write 'fq_codel' to 'net/core/default_qdisc', ignoring: No such file or directory
Couldn't write '4194304' to 'kernel/pid_max': Invalid argument

[1] https://paste.ubuntu.com/p/TQhpFWYzK7/