The NixOS IPA module adds ConditionPathExists=/etc/krb5.keytab drop-ins
for auth-rpcgss-module.service and rpc-gssd.service via systemd.units.
In LXC containers with keytabs those conditions pass, the services start,
and then fail because auth_rpcgss can't be loaded and rpc_pipefs doesn't
exist in the container namespace.
Use lib.mkForce on our systemd.units text to win the conflict with NixOS's
existing definitions, and include ConditionVirtualization=!container
alongside the ConditionPathExists conditions so the services are skipped
(inactive, not failed) in containers that have a keytab.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>