Container Networking

We need to access the container from outside world and the container running on different hosts have to communicate each other.

Here we will see how can we do it with bridging.

Traditional networking

Network Network

Create a veth pair on Host.

$ sudo ip link add veth0 type veth peer name veth1
$ sudo ip link show

Create a network namespace

$ sudo ip netns add bash-nw-namespace
$ sudo ip netns show

Connect one end to namespace

$ sudo ip link set veth1 netns bash-nw-namespace
$ sudo ip link list

Resulting network

Network Network

Create a Bridge interface

$ sudo brctl addbr cbr0

Add an external interface to bridge

$ sudo brctl addif cbr0 enp0s9
$ sudo brctl show

Connect other end to a switch

$ sudo brctl addif cbr0 veth0
$ sudo brctl show

Resulting network

Network Network

Assign IP to interface

$ sudo ip netns exec bash-nw-namespace bash
$ sudo ip addr add 192.168.56.10/24 dev veth1
$ sudo ip link set lo up
$ sudo ip link set dev veth1 up

Access container IP from outside

Like bridging , we can opt other networking solutions.

Later we will see how Weave Network and Calico plugins works. You may read bit more on Docker networking basics on below blog post

Docker networking