In order to identify the relation between the veth on the host and eth0 interface on the container, we can check the interfaces on the container using the following command:
[root@docker js]# docker exec -it dc ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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
94: eth0@if95: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP
link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0
valid_lft forever preferred_lft forever
We can see that the eth0 is suffixed by if[number]. This number also prefixed to corresponding the host virtual interface (veth). To validate this, check the network interfaces on the host:
[root@docker js]# ip a | egrep veth
93: veth5e8ceb7@if92: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default
95: veth3de0e04@if94: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default