Problems using "network" section in docker-compose.yml

Product support
1

Hi all,

I’ve posted here that we’re working on OpenThread Border Router support. As a part of that we need to support IPv6/IPv4 routing.

@see: Containerising OpenThread Border Router (OTBR) for OpenThread [WIP] - #3 by ajlennon

From reading around this seems to involve adding a network section to the docker-compose.yml file. However when I add this in “strange things happen” with the network continually being added and removed / service restarting.

To try to get to the bottom of this I created a very simple hello-world app that just runs a script that sleeps.

This is the docker-compose.yml file

version: '2'

services:
   hello-world:
     build: ./hello-world

     network_mode: host
     networks:
       ipv6net:
          ipv6_address: 2001:3984:3989::20

networks:
   ipv6net:
     driver: bridge
     enable_ipv6: true
     ipam:
       driver: default
       config:
       - subnet: 2001:3984:3989::/64
         gateway: 2001:3984:3989::1

When I balena push hello-world to my fleet I get the constant cycling behaviour

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image2254×1331 467 KB

EDIT

I’ve just spotted the above has network: host. When I remove this I get a similar kind of error

version: '2'

services:
   hello-world:
     build: ./hello-world

#     network_mode: host
     networks:
       ipv6net:
          ipv6_address: 2001:3984:3989::20

networks:
   ipv6net:
     driver: bridge
     enable_ipv6: true
     ipam:
       driver: default
       config:
       - subnet: 2001:3984:3989::/64
         gateway: 2001:3984:3989::1

image
image2254×1331 397 KB

Can anybody advise?

Thanks, Alex

1 Like
2

@mpous did a simple test case. Happy to share this to support if anybody fancies a look?

1 Like
3

And this is what journalctl is looping doing

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image1920×1134 212 KB

4

Searching for the particular error I found this: docker throws error when adding IPv6 route · Issue #2432 · moby/libnetwork · GitHub. However I am not certain that is what is really causing the restart itself. Checking further.

1 Like
5

I’m not sure what to look for in the underlying host (if anything). You’re more than welcome to get into the board I have running this test here if that’s of any use @majorz

6

I did more digging and from what I see I assume ipv6 is simply not enabled in balenaEngine for containers. Thanks for offering access to the board - for now I believe this should be easily reproducible on our side. I will spawn a VM now with balenaOS and see whether that will be the case. I will let you know what I find.

1 Like
7

Very interesting - thanks for looking at this @majorz. Yes please do as we’re super keen here to get on with containerising OTBR :slight_smile:

8

Sorry for not getting back to you earlier, but we have identified the problem on our side. It is just that balenaEngine/Docker needs extra configuration for this - Enable IPv6 support | Docker Documentation. Next step for us is to make this manually work on a live device. Afterwards we will discuss internally how this could be possibly enabled more specifically.

1 Like
9

Brilliant! Anything I can do at this end to enable it in the meantime?

10

From my debugging I saw that supervisor needs also an ipv4 address to be specified. Next to the ipv6 address can you please add an ipv4 address as well and let me know whether this time it works for you?

version: '2.4'

services:
  hello-world:
    build: ./hello-world

    networks:
      customnet:
        ipv4_address: 172.28.0.2
        ipv6_address: 2001:3984:3989::20

networks:
  customnet:
    enable_ipv6: true
    ipam:
      driver: default
      config:
      - subnet: 172.28.0.0/14
        gateway: 172.28.0.1
      - subnet: 2001:3984:3989::/64
        gateway: 2001:3984:3989::1
1 Like
11

Awesome ! That fixes it thanks! I will go back to try this with the OTBR service!

12

Thanks, please try it with the service as I am not completely sure routing will properly work although the addresses are available now inside the container.

13

The OTBR service runs up. It’s not quite working right but I’ll take a look at what’s going on tomorrow. It certainly isn’t restarting all the time like it was. Thanks again !!!

14

I am pretty sure that is all looking really good now thanks @majorz. I still have one problem which is to do with inter-container network setup but I will move that chat back over to the OTBR issue