Also reduce the allowed port range as the total number of containers
per host is typically less than 1K.
This change helps in scenarios where there are other services on
the same host that uses ephemeral ports in iptables manipulation.
The workflow requires changes in docker engine (
https://github.com/moby/moby/pull/40055) and this change. It
works as follows:
1. user can now specified to docker engine an option
--published-port-range="50000-60000" as cmdline argument or
in daemon.json.
2. docker engine read and pass this info to libnetwork via
config.go:OptionDynamicPortRange.
3. libnetwork uses this range to allocate dynamic port henceforth.
4. --published-port-range can be set either via SIGHUP or
restart docker engine
5. if --published-port-range is not set by user, a OS specific
default range is used for dynamic port allocation.
Linux: 49153-60999, Windows: 60000-65000
6 if --published-port-range is invalid, that is, the range
given is outside of allowed default range, no change takes place.
libnetwork will continue to use old/existing port range for
dynamic port allocation.
Signed-off-by: Su Wang <su.wang@docker.com>
Su Wang