Multiple softflowd instances
============================
The Debian packaging of softflowd supports handling of multiple
instances. One instance is already shipped as
`/etc/softflowd/default.conf`.
To add more instances, create a file `/etc/softflowd/.conf`
where `` should be constructed using the "Portable Filename
Character Set"[1] and must not start with a dot (i.e. must not be a
hidden file).
The file is a POSIX shell fragment and defines two variables:
* `interface`: The interface to listen on, or `all`
Without an interface definition, the instance will be ignored.
* `options`: Additional options to pass to softflowd.
On systemd, the file is read as a key/value store, for details see
`EnvironmentFile=` systemd.exec(5).
On SysV init, the file is run as a shell script.
The pidfile will be stored at `/run/softflowd/.pid`[2], do not
attempt to override that. The control socket for softflowctl is at
`/run/softflowd/.ctl`. You still may override these using the
`-c` options in the `options=` string, last match wins.
The softflowctl program will query the "default" instance by default.
To add a new instance:
Create an according configuration file first.
On systemd, run `systemctl daemon-reload`, then
`systemctl start softflowd@.service`.
On SysV init, run `serivce softflowd start `.
[1] Upper and lower case characters, digits, dot, underscore, dash.
For pure visual reasons, the dash should be avoided on systemd as
it's escaped in the service name.
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_282
[2] On SysV init systems: `/var/run/softflowd/.pid`, likewise
for the control socket.