gchristensen: ```➜  ~ sudo nixos-rebuild switch --upgrade             
[sudo] password for william: 
unpacking channels...
building Nix...
building the system configuration...
activating the configuration...
setting up /etc...
reloading user units for william...
setting up tmpfiles
the following new units were started: cpu-throttling.service
warning: the following units failed: apparmor.service

● apparmor.service
   Loaded: loaded (/nix/store/csxmp1iy3f5ijy8m0ajx6ch5n8milljc-unit-apparmor.service/apparmor.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Wed 2019-05-08 10:29:31 EDT; 17ms ago
  Process: 2996 ExecStart=/nix/store/5v3ysffjypsndwxkh16byzaa3g55lz4g-apparmor-parser-2.13.1/bin/apparmor_parser -rKv -I /nix/store/gj3zvpgbsnx85nbbrpb5s2kjz4y85w80-apparmor-profiles-2.13.1/etc/apparmor.d -I /nix/store/pmgymay0liaz5xy65z9n029v2qn6k79v-lxc-3.1.0/etc/apparmor.d /nix/store/pmgymay0liaz5xy65z9n029v2qn6k79v-lxc-3.1.0/etc/apparmor.d/usr.bin.lxc-start (code=exited, status=1/FAILURE)
 Main PID: 2996 (code=exited, status=1/FAILURE)

May 08 10:29:31 helium systemd[1]: Starting apparmor.service...
May 08 10:29:31 helium apparmor_parser[2996]: Warning from stdin (line 1): config file '/etc/apparmor/parser.conf' not found
May 08 10:29:31 helium apparmor_parser[2996]: Cache read/write disabled: interface file missing. (Kernel needs AppArmor 2.4 compatibility patch.)
May 08 10:29:31 helium apparmor_parser[2996]: Warning: unable to find a suitable fs in /proc/mounts, is it mounted?
May 08 10:29:31 helium apparmor_parser[2996]: Use --subdomainfs to override.
May 08 10:29:31 helium systemd[1]: apparmor.service: Main process exited, code=exited, status=1/FAILURE
May 08 10:29:31 helium systemd[1]: apparmor.service: Failed with result 'exit-code'.
May 08 10:29:31 helium systemd[1]: Failed to start apparmor.service.
warning: error(s) occurred while switching to the new configuration```