Chris Swan's ONUG NYC talk - Container Networks

Copyright 2014 Open Networking User Group. All Rights Reserved Confidential Not For Distribution
October 28-29, 2014

Container Networks and
Network Containment
Chris Swan
CTO CohesiveFT
@cpswan

Part 1 – Container Networking
3

4
TL;DR
docker0 bridge is the heart of default networking
Plus some iptables magic
Docker can help link your containers (on a single host)
But it’s easier with a compositing tool
There are advanced options
On a single host
On multi hosts
and advanced tools

Do I first need to explain
Docker and containers?
5

Build, Ship > Run?
6
Image credit http://www.mediaagility.com/2014/docker-the-next-big-thing-on-cloud/

Docker Hub
7
Image credit http://blog.docker.com/2014/06/announcing-docker-hub-and-official-repositories/

Demo time

Why me?
9

Conceived last summer – released this April
1

The basics
1

1
Let’s start with a regular host
eth0
10.0.1.1

1
Install Docker
eth0
10.0.1.1
docker0
172.17.42.1

1
Start a container
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab

1
Start another container
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab
eth0
172.17.0.2
veth9c5d

iptables magic
1

1
Connecting to the outside world
$ sudo iptables -t nat -L –n
...
Chain POSTROUTING (policy ACCEPT)
target prot opt source destination
MASQUERADE all -- 172.17.0.0/16 !172.17.0.0/16
...

1
Connecting from the outside world
$ sudo docker run –dp 1880:1880 cpswan/node-red
$ sudo docker ps
CONTAINER ID IMAGE COMMAND
CREATED STATUS PORTS
NAMES
7696169d9438 cpswan/node-red:latest node red.js 2
weeks ago Up 2 weeks 0.0.0.0:1880->1880/tcp
backstabbing_davinci
$ sudo iptables -t nat -L –n
...
Chain DOCKER (2 references)
target prot opt source destination
DNAT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp
dpt:1880 to:172.17.0.7:1880

Container linking
1

2
From the docker command line
From the outside:
# start the database
sudo docker run -dp 3306:3306 --name todomvcdb
-v /data/mysql:/var/lib/mysql cpswan/todomvc.mysql
# start the app server
sudo docker run -dp 4567:4567 --name todomvcapp
--link todomvcdb:db cpswan/todomvc.sinatra
On the inside:
dburl = 'mysql://root:pa55Word@' + ENV['DB_PORT_3306_TCP_ADDR'] +
'/todomvc'
DataMapper.setup(:default, dburl)

2
Simplify life with Fig
fig.yml:
todomvcdb:
image: cpswan/todomvc.mysql
expose:
- "3306"
volumes:
- /data/mysql:/var/lib/mysql
todomvcapp:
image: cpswan/todomvc.sinatra
ports:
- "4567:4567"
links:
- todomvcdb:db
I still need this on the inside:
dburl = 'mysql://root:pa55Word@' + ENV['DB_PORT_3306_TCP_ADDR'] +
'/todomvc'
DataMapper.setup(:default, dburl)

Other networking modes
2

2
--net=host
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab
eth0
172.17.0.2
veth9c5d

2
--net=container:$container2
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab
eth0
172.17.0.2
veth9c5d

2
--net=none
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab
eth0
172.17.0.2
veth9c5d

Connecting containers between
machines
2

2
Marek Goldmann did this with OVS

2
A more generic approach (ODCA)

Flocker
2

Weave
3

Still want more…
3

3
Pipework etc.
Pipework:
• Create bridges
• Attach to container interfaces
• Attach to host interfaces
• and much more…
Tenus:
• Golang package offering programmatic
network configuration along similar lines to
Pipework

libchan
‘A low level component that we can use as a communication layer
that we can use across the board for all the different aspects of
communication within Docker’
Solomon Hykes – DockerCon 2014 (my emphasis)
What it is – Golang like channels over the network
‘A lightweight communication protocol for distributed systems’
What it does – yet to be revealed
3

Gotchas
3

3
Our old enemy the network hub
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab
eth0
172.17.0.2
veth9c5d

3
A bit like a home network
eth0
10.0.1.1
docker0
172.17.42.1
eth0
172.17.0.1
veth67ab
eth0
172.17.0.2
veth9c5d

Host as router can be painful
• VirtualBox requires specific network adaptors (in a specific configuration) to
play nicely with pipework
• Even with source/destination checks disabled pipework won’t play nicely on
EC2
– Mileage may vary on other clouds, but some don’t even have the option to flick that
bit (or make it very hard to get at)
3

The end of this part (nearly)
3

Docker makes a great place to run
L4-7 Network Application Services
3

Part 2 –Network Containment
4

4
TL;DR
Hard shell and soft centre has never served us well
The pressure to move on is mounting
Finer grained network segregation was too expensive in
hardware
Software makes it achievable
We’re seeing the dawn of application centric networking
and the Application Security Controller

Enterprise networks and perimeters
4

The confectionary networking model
Hard crunchy perimeter
Soft chewy centre
Image credit CC by Sandra Fauconnier
https://www.flickr.com/photos/spinster/4369608/

Pretty much everybody has a ‘demilitarized zone’
DMZ
Intranet

Sophisticated organisations have an application server zone
DMZ
Intranet
ASZ

Global scale makes things messy
DMZ
Intranet
ASZ
DMZ
ASZ
DMZ
ASZ
Europe Americas Asia

Some even have a ‘domain zoning concept’

This is VERY expensive when done with hardware

But potentially cheap and flexible if done in software

‘Microsegmentation’ – the VMware view
Image credit http://vinfrastructure.it/2014/09/micro-segmentation-with-nsx/

What’s driving this?

Are you being asked to look at this?

In particular this:

Application centric networking

What’s the right granularity?
Microservice Service Service family

The sweet spot likely depends on containment of business data
Microservice Service Service family

To each their own
Encrypted
overlay
Firewall
NIDS TLS
Cache
Load balancer
Proxy

Using an ‘Application Security Controller’
Encrypted
overlay
Firewall
NIDS TLS
Cache
Load balancer
Proxy

Wrapping up

6
TL;DR
Hard shell and soft centre has never served us well
The pressure to move on is mounting
Finer grained network segregation was too expensive in
hardware
Software makes it achievable
We’re seeing the dawn of application centric networking
and the Application Security Controller

Questions?
chris.swan@cohesiveft.com
@cpswan

Chris Swan's ONUG NYC talk - Container Networks

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