Hello my Frind about docker-dns

[bnfinet]

Thanks for asking.

docker-dns serves a couple different use cases

• service discovery using SRV records
• providing a bridge between non-docker (legacy) systems and docker containers
• multi docker-host environment support
• easing access to containers

I support a dev team that sometimes needs to log into containers via ssh in order to analyze various aspects of our integration environment. It's been very handy to write a wrapper script around ssh which looks up the mapped ssh port provided by the SRV records from docker-dns. That way even after restarting containers (with new code/configuration), the name is stable even if the port and internal IP has changed.

Because docker-dns supports multiple docker hosts, we can move that container to a different host and it's still available for SRV lookup.

wrt to --link, I sometimes prefer to use dns, though I see the utility of both. For example we run a hipache container for reverse proxy. I'd prefer not to have to have a dependency on the hipache --link on a variety of containers. Furthermore for some things like hipache which feel like docker infrastructure, I'd just assume have the ability to interact with them from the host or from other machines.

Also there are the dynamic aspects of SRV service discovery. If I bring up a new redis container, I'd like the application containers that are consuming our redis service to be able to find that new redis container without having to go back and touch them all.

There's all this but it's also awfully nice to be able to ping a container by it's host or image name and find it quickly. That saves me tons of time when I'm wiring things up.

Please do let me know if you try out docker-dns, and please post any other questions (or bugs) here.