1. Docker Networking
with Weave
johann Romefort - co-founder @ getrainbow.com

2. Docker Networking
• Linux Bridge based
• Work as this:
• Creates a Virtual Eth Bridge on docker0
• Assign docker0 bridge an IP unused on host
• create a vethXXXX interface
• map vethXXXX to ethX on host

3. Docker networking
host1
Container1
docker0
vethXXX
eth0
eth0

4. Docker networking
host1
Container1
docker0
Container2
eth0
vethXXX
vethXXX
eth0eth0

5. Docker networking
host1
wordpress
docker0
mysql
eth0
Container Interconnection through docker0
That’s how container linking works:
exporting host information in local ENV
Container communicate
through open ports
$docker run -d
--name mysql
-e MYSQL_DATABASE=WORDPRESS
-e MYSQL_USER=wp
-e MYSQL_PASSWORD=huhu
orchardup/mysql
$docker run
--name wordpress
--link mysql:mysql -d
-e WORDPRESS_DB_USER=wp
-e WORDPRESS_DB_NAME=WORDPRESS
-e WORDPRESS_DB_PASSWORD=huhu
wordpress
vethXXX
vethXXX
eth0eth0

6. Docker networking
host1
wordpress mysql
eth0
Container exposing public port
docker0
$docker run -d
--name mysql
-e MYSQL_DATABASE=WORDPRESS
-e MYSQL_USER=wp
-e MYSQL_PASSWORD=huhu
orchardup/mysql
$docker run
--name wordpress
--link mysql:mysql -d
-e WORDPRESS_DB_USER=wp
-e WORDPRESS_DB_NAME=WORDPRESS
-e WORDPRESS_DB_PASSWORD=huhu
-p 80:80
wordpress
$sudo docker exec -it wordpress bash
:80
vethXXX
vethXXX
eth0eth0

7. Weave
• Allows containers to all behave as if
they were connected to the same
physical network switch
• Connectivity to outside world

8. Weave features
• Multi-Datacenter support
• Traverse firewalls
• Encrypted links
• Multi-hop routing
• Container mobility
• Fault tolerance

9. It’s demo time!

10. Weave network
host1 host2

11. Weave network
e
weave
router
e
weave
router
eth0
host 1 host 2
container1 container2
$weave launch
$weave run 10.0.1.1/24 -d
—name container1 ubuntu /bin/bash
$nc -lk -p 4422
weave launch 10.0.1.1
weave run 10.0.1.2/24 -d
—name container2 ubuntu /bin/bash
echo 'Hello, world.' | nc 10.0.1.1 4422

12. Weave network
e
weave
router
e
weave
router
eth0
host 1 host 2
container2 container2
weave expose 10.0.1.102/24
ping 10.0.1.1
ping 10.0.1.2
iptables -t nat -A PREROUTING -p tcp -i eth0
--dport 2211 -j DNAT --to-destination
10.0.1.1:4422
10.0.1.102

13. Demo
• Launching 3 VMs
• Installing weave on each
• Launching weave router
• Launching containers with weave
• Dynamically attaching a container to
weave

14. Thank you!
twitter: @romefort
email: romefort@gmail.com