Add subnet setting for Proxy user

[tsjsdbd]

By default, Docker use 172.17.0.0/16 to docker0 interface. like:

docker0   Link encap:Ethernet  HWaddr 02:42:91:7b:0f:21  
          inet addr:172.17.0.1  Bcast:172.17.255.255  Mask:255.255.0.0

and by default, Docker-compose will use 172.18.0.0/16, 172.19.0.0/16 ...and so on, to new Bridge, like:

br-c401dc9ce9fd Link encap:Ethernet  HWaddr 02:42:ac:c9:28:9e  
          inet addr:172.18.0.1  Bcast:172.18.255.255  Mask:255.255.0.0

But, My environment have proxy endpoint: 172.18.22.221, if can not setting subnet of docker-compose, the default subnet adderess will conflict with my Proxy, which cause it can not work.

so, add subnet setting is meaningful for Proxy user : )

[tsjsdbd]

@fhueske ，
It's no effect on the Non-Proxy user, just more friendly for proxy user。

[tsjsdbd]

@fhueske @alpinegizmo @knaufk @rmetzger
any suggesting？ I can improve the PR like changing the default CIDR value if you need.

[fhueske]

Thanks for the PR @tsjsdbd and sorry for the delay.
The change looks good (based on my somewhat rusty networking knowledge).
I'll try it out and have a closer look tomorrow.
Best, Fabian

[patricklucas]

@tsjsdbd I think this issue doesn't affect that many people, and picking another arbitrary IP range (like 10.103/16) could possibly break things for other people who happen to already use it.

Have you tried setting the default-address-pools setting on your Docker daemon? (see this comment) I just tried it on my machine (Docker Desktop 2.1.0.5 on Mac) and it worked fine.

[tsjsdbd]

@patricklucas I realize that default CIDR using 10.103/16 may not very generic, but still want to leave a chance to those people who may facing this problem. So I will improve the PR by changing the default CIDR value to 172.18/16 .
And for Docker daemon conf, as it is allready used before using this playground(maybe some container is running), so it's better not change Docker，but have chance to change the new comming component, right?。
hope i can involve in flink community , Flink is really good.

[xueIove]

Can you share the metadata?