Multiple softflowd instances
Starting with version 0.9.9-4, the Debian packaging of softflowd
supports handling of multiple instances. One instance is already
shipped as `/etc/softflowd/default.conf` (which is a re-used
`/etc/default/softflowd` when upgrading from an older version).
To add more instances, create a file `/etc/softflowd/.conf`
where `` should be constructed using the "Portable Filename
Character Set" and must not start with a dot (i.e. 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
On SysV init, the file is run as a shell script.
The pidfile will be stored at `/run/softflowd/.pid`, 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 `.
 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.
 On SysV init systems: `/var/run/softflowd/.pid`, likewise
for the control socket.