Docker Network Demo - Part 2

Opening a new session with the host.  I'm going to create a second running container and see if they can communicate.

nelson@lab1:~$ docker run -it alpine /bin/sh

/ #

Verifying it is a second shell…

nelson@lab1:~$ docker ps

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

4a567ec8d878        alpine              "/bin/sh"           32 seconds ago      Up 32 seconds                           serene_jennings

60f137369165        alpine              "/bin/sh"           14 hours ago        Up 14 hours                             nauseous_meninsky

Let's look at the IP addressing

/ # ifconfig -a

eth0      Link encap:Ethernet  HWaddr 02:42:AC:11:00:03

          inet addr:172.17.0.3  Bcast:0.0.0.0  Mask:255.255.0.0

          inet6 addr: fe80::42:acff:fe11:3%32717/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:26 errors:0 dropped:0 overruns:0 frame:0

          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0

          RX bytes:5575 (5.4 KiB)  TX bytes:648 (648.0 B)

Ping Externally Success

/ # ping 8.8.8.8

PING 8.8.8.8 (8.8.8.8): 56 data bytes

64 bytes from 8.8.8.8: seq=0 ttl=57 time=24.538 ms

64 bytes from 8.8.8.8: seq=1 ttl=57 time=22.519 ms

64 bytes from 8.8.8.8: seq=2 ttl=57 time=22.623 ms

64 bytes from 8.8.8.8: seq=3 ttl=57 time=23.002 ms

64 bytes from 8.8.8.8: seq=4 ttl=57 time=22.303 ms

^C

--- 8.8.8.8 ping statistics ---

5 packets transmitted, 5 packets received, 0% packet loss

round-trip min/avg/max = 22.303/22.997/24.538 ms

Question:  Can the two containers communicate with each other?

.3 to .2  Success

/ # ping 172.17.0.2

PING 172.17.0.2 (172.17.0.2): 56 data bytes

64 bytes from 172.17.0.2: seq=0 ttl=64 time=0.175 ms

64 bytes from 172.17.0.2: seq=1 ttl=64 time=0.128 ms

64 bytes from 172.17.0.2: seq=2 ttl=64 time=0.131 ms

64 bytes from 172.17.0.2: seq=3 ttl=64 time=0.130 ms

64 bytes from 172.17.0.2: seq=4 ttl=64 time=0.175 ms

^C

--- 172.17.0.2 ping statistics ---

5 packets transmitted, 5 packets received, 0% packet loss

round-trip min/avg/max = 0.128/0.147/0.175 ms

.2 to .3 Success

/ # ping 172.17.0.3

PING 172.17.0.3 (172.17.0.3): 56 data bytes

64 bytes from 172.17.0.3: seq=0 ttl=64 time=0.144 ms

64 bytes from 172.17.0.3: seq=1 ttl=64 time=0.128 ms

64 bytes from 172.17.0.3: seq=2 ttl=64 time=0.129 ms

64 bytes from 172.17.0.3: seq=3 ttl=64 time=0.122 ms

64 bytes from 172.17.0.3: seq=4 ttl=64 time=0.126 ms

^C

--- 172.17.0.3 ping statistics ---

5 packets transmitted, 5 packets received, 0% packet loss

round-trip min/avg/max = 0.122/0.129/0.144 ms

Here's what it looks like.

Containers communicating on the bridge

http://www.abusedbits.com/2016/07/docker-network-demo-part-3.html