Modify chronyd.service to handle cases where OPTIONS is undefined,
which occurs when /etc/sysconfig/chronyd doesn't exist or doesn't set
the variable. This prevents the warning:
"chronyd.service: Referenced but unset environment variable
evaluates to an empty string: OPTIONS"
On Linux, if the NOTIFY_SOCKET variable is set, send a "READY=1"
and "STOPPING=1" message to the Unix domain socket after initialization
and before finalization respectively. This is used with the systemd
"notify" service type as documented in the sd_notity(3) man page. It's
a recommended alternative to the "forking" service type, which does not
need the PID file to determine the main process.
Support pathname Unix sockets only. Abstract sockets don't seem to be
used by systemd for notifications since version 212.
Switch the example services to the notify type, but keep the PID
file. It's still useful to prevent start of other chronyd instances.
systemd doesn't seem to care about the content of the file and should
just remove it in case chronyd didn't terminate cleanly.
Suggested-by: Luca Boccassi <bluca@debian.org>
This is a more restricted version of the chronyd service intended for
minimal NTP/NTS client configurations. The daemon is started without
root privileges and is allowed to write only to its own runtime, state,
and log directories. It cannot bind to privileged ports in order to
operate as an NTP server, or provide monitoring access over IPv4/IPv6.
It cannot use reference clocks, HW timestamping, RTC tracking, and other
features.
