add new limit: max_connections_per_systemd_unit
Submitted by Alban Crequy
Assigned to D-Bus Maintainers
dbus-daemon already has the following limits:
- max_completed_connections: (default|system bus)=2048 (session bus)=100000
- max_connections_per_user: (default|system bus)=256 (session bus)=100000
So an user on the system bus cannot use all connections and prevent other users from connecting to the bus.
But this per-user granularity does not allow to distinguish different services running as the same user. For example, both Avahi and ConsoleKit are system services, running as the same user root, and they connect to the system bus. If one of them starts to use all the available connections due to a bug, the other will not be able to connect.
To fix this issue, this patch introduces a new configurable limit:
- max_connections_per_cgroup: (default|system bus)=256 (session bus)=100000
The default values are large enough to avoid impacting current systems but an administrator could restrict it more.