Docker: how to connect two bridges

Question

As you know after Docker 1.9 we can create bridges to connect containers.

I have created two custom bridges: bridge A 172.18.0.1 and bridge B 172.19.0.1.

Now I have a container1 on bridge A, and a container2 on bridge B called "mailServer".

The container1 needs to reach container2 by a DNS, how should I do this? Because they are on different bridges so they cannot talk to each other. Do I need a router and can I achieve this by Docker?

This is a new feature of Docker and I didn't find much information. Thanks.

score 14 · Answer 1 · answered May 31 '16 at 20:11

14

To connect container2 to container1 you can also connect it to bridgeB

$ docker network connect bridgeB container1

This will allow container1 to connect to container2 by IP address, DNS names would still have to be updated manually afaik.

More information in the Docker networking guide here.

answered May 31 '16 at 20:11

arunkumar

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Is there a more semantic way to connect two custom bridge networks? `docker network connect NETWORK1 NETWORK2` is not supported. Is connecting two custom bridge networks bad idea (might be bad idea since it's not supported)? Why? – Sida Zhou Oct 24 '18 at 09:22

score 13 · Accepted Answer · answered Apr 11 '16 at 09:36

13

You can try making use of the veth peer so that you can connect two bridges. Make sure you are rename and names respectively with the one you configured.

ip link add veth0 type veth peer name veth1
ifconfig veth0 up
ifconfig veth1 up
brctl addif <D1-A-Bridge> veth0
brctl addif <D2-A-Bridge> veth1

answered Apr 11 '16 at 09:36

Viswesn

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if Bridge A and Bridge B is not in a same subnet.the connection is not useful. – focus zheng Feb 26 '21 at 02:05

score 0 · Answer 3 · answered Apr 11 '16 at 12:13

If you want to connect two bridges, you can use a pair of patch ports with open v-switch . The follow example creates bridges br0 and br1, adds eth0 and tap0 to br0, adds tap1 to br1, and then connects br0 and br1 with a pair of patch ports.

   ovs-vsctl add-br br0
   ovs-vsctl add-port br0 eth0
   ovs-vsctl add-port br0 tap0
   ovs-vsctl add-br br1
   ovs-vsctl add-port br1 tap1
   ovs-vsctl \
       -- add-port br0 patch0 \
       -- set interface patch0 type=patch options:peer=patch1 \
       -- add-port br1 patch1 \
       -- set interface patch1 type=patch options:peer=patch0

score 0 · Answer 4 · answered Feb 26 '21 at 02:07

0

set Forward chain in filter table ,allow Bridge-A and Bridge-B forward.if you want to access internet,set masqurade in Postrouting chain of nat table

answered Feb 26 '21 at 02:07

focus zheng

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Docker: how to connect two bridges

4 Answers4