docker swarm container bind address other than 0.0.0.0

Question

I got a multi-node docker swarm setup with the following interfaces:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:8d:c0:4d brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global dynamic eth0
       valid_lft 47333sec preferred_lft 47333sec
    inet6 fe80::a00:27ff:fe8d:c04d/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:fe:3f:4d brd ff:ff:ff:ff:ff:ff
    inet 10.0.1.2/24 brd 10.0.1.255 scope global eth1
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fefe:3f4d/64 scope link 
       valid_lft forever preferred_lft forever
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:94:ee:64:8f brd ff:ff:ff:ff:ff:ff
    inet 10.0.1.2/24 brd 10.0.1.255 scope global docker0
       valid_lft forever preferred_lft forever
9: docker_gwbridge: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:12:4b:f2:fa brd ff:ff:ff:ff:ff:ff
    inet 172.18.0.1/16 brd 172.18.255.255 scope global docker_gwbridge
       valid_lft forever preferred_lft forever
    inet6 fe80::42:12ff:fe4b:f2fa/64 scope link 
       valid_lft forever preferred_lft forever

When starting the most simple container stack docker swarm deploy -c simple.yml simple

version: "3.7"
services:
  whoami:
    image: traefik/whoami
    ports:
      - 80:80

The container get placed and the service gets bound to 0.0.0.0. Not exactly ideal. Better would be for the container to bind to the eth1=10.0.1.2/24 interface. Ideally also lo - but that would be just the icing on the cake.

What I've tried is to start the docker instances with their respective IPs from the network.

--ip ip Default IP when binding container ports (default 0.0.0.0)

So based on the docs for example: dockerd --ip 10.0.1.2. Unfortunately that does not seem to change a thing.

I am using Docker version 20.10.4, build d3cb89e.

Any advise what I might be missing?

score 2 · Answer 1 · answered Mar 01 '21 at 18:17

Currently it's not possible to bind a swarm service to a specific IP. See this more than four year old issue: https://github.com/moby/moby/issues/26696

You can init your swarm with the --advertise-addr --data-path-addr and --listen-addr option bound to your eth1 interface to limit some of the internal swarm traffic to this interface, but this will not really solve the problem.

docker swarm container bind address other than 0.0.0.0

1 Answers1