Dynamically bind both tcp and udp on a same port

[xiamx]

I have a service that listens on a port for both tcp and udp. I'd like to run something like docker run -p 8080 -p 8080/udp -i -t image_name and have docker use a same port on the host for tcp and udp.

Where should I dig into if I want to implement this myself?

[crosbymichael]

just do

docker run -p 8080:8080 -p 8080:8080/udp -i -t image_name

[xiamx]

I'm spawning these containers ondemand, so i can't hardcode the port number on the host

[crosbymichael]

oh, i understand now

[savaki]

I've got the same issue

[savaki]

I would like -P to bind the udp and tcp to the same port, not different ones

[xiamx]

Any hint on which part of the sourcecode should I dig into to patch it myself?

[LK4D4]

@xiamx It is in daemon/networkdriver/portallocator/portallocator.go, RequestPort function, you want proto as []string. It is not very hard to implement it.
@crosbymichael what do you think about it? I think that it is pretty cool feature that costs nothing to implement.

[crosbymichael]

I would rather not do this if possible. I would rather have it stay explicit but I am up for suggestions.

[mileswilson]

I'd love to see an explicit 'both' option. There are applications (serf for instance) that want to communicate on the same port for both udp and tcp traffic - whilst I can do this if I hard code the port numbers, that takes away a really nice feature of docker, the dynamic port generation.

'-p PORT/tcp-udp' to have it pick a random port, but allow both tcp and udp traffic would be of tremendous help.

[bfosberry]

Bump, this is my exact issue and I would love something like

EXPOSE 12345
EXPOSE 12346/udp
EXPOSE 12347udptcp

[bfosberry]

I am using opinionated servers that allow you to specify a port number, then bind both TCP and UDP to it, which docker may separately remap. Outside the container the UDP and TCP is assumed to be on the same port

[brahmaroutu]

Currently Docker build supports
EXPOSE 12345
EXPOSE 12346/udp
EXPOSE 12347/tcp
EXPOSE 12347/udp

I believe if this is good for your use case then we should close this issue.

[bfosberry]

It does not, I need a single external port number mapped to both TCP and UDP inside the container

[brahmaroutu]

I will give it a try, add code to support "EXPOSE 12347/udptcp" format.

[savaki]

Can I play devils advocate and ask why a special tag is needed? Why is the
following insufficient?

EXPOSE 12345
EXPOSE 12345/udp

Seems like this would be trying to simplify the code at the expense of the
usability. I believe the use case that we're all experiencing is that

docker run -P ...

with the aforementioned expose would bind udp and tcp on separate ports.
This is unintuitive at the least and problematic for a number of services
e.g. serf, consul.

M

On Wed, Oct 8, 2014 at 8:59 AM, Srini Brahmaroutu notifications@github.com
wrote:

I will give it a try, add code to support "EXPOSE 12347/udptcp" format.

—
Reply to this email directly or view it on GitHub
#4635 (comment).