The vars can be customized before enabling the plugin with e.g.:
docker plugin set $PLUGIN_NAME set WEAVE_MTU=8160
The ARP settings apply to "weave" bridge. In order to manipulate them,
we bind mount the host's /proc to /host/proc.
(The mount type of /proc changed to bind, Otherwise (when type =
"proc"), the kernel does not propagate pids of host processes as the
plugin runs in a separate PID ns.)
Persistence relies on weave.db which is stored under
/var/lib/weave/weave.db on the host.
NOTE: we do not persist peer list for plugin-v2, as it gets
restored from existing alive master nodes during the peer discovery.