Microservices using relocatable Docker containers

Medallia © Copyright 2015. 2
Docker Buenos Aires
• Medallia
○ “Software to improve the customer experience”
○ “Aggregating 1 Billion documents in 1 second or less”
• Mauricio Garavaglia
○ Software Engineer
○ mauricio@medallia.com
• 2015-05-21
Bienvenidos!!!

Docker 101

Problem: Matrix from Hell

Problem: Efficient use of Resources
Solution But...
Time Sharing! - Your library 2.0 clashes with my library 1.0
- Increase attack vectors
Virtualization! - Isolation but too much overhead!
- Seriously, overhead!
Containers! ...

“Lightweight Virtual Machine”

Docker
Containerization for the masses
Docker
Container
Linux cgroups
Linux
namespaces
Images
(Layered FS)

Server
Docker Architecture
Docker Client Docker Daemon
container 1
container 2
container 3
container 4
Rest API
Docker
HubImages

Checkout and have fun!
https://www.docker.com/tryit/

Microservices using relocatable
Docker containers
Thorvald Natvig (thorvald@medallia.com)
Mauricio Garavaglia (mauricio@medallia.com)

• Docker for everything!
• Docker for applications!
• Docker for load-balancers!
• Docker for zookeeper! And DNS!
• Docker for databases!
Problem to solve
Want a reliable, flexible data-center

Problem to Solve Today
Relocating non-movable services
DataCenter Firewall
Host: 10.1.2.3:80
Host: 10.1.2.5:80
172.17.0.3:80 nginx
Host: 10.1.2.4:2181
172.17.1.0:2181 zookeeper
172.17.1.2:80 application

Docker Bridged Networking Model
host1
container 1
eth0
10.1.2.3/24
172.16.1.1
172.16.1.2
docker0
veth0 veth1

Default (Bridged) Strategy
● Creates a pair of veth.
● Moves one to the container
namespace.
● Renames the container veth to
eth0
● Attaches the host veth to the
docker0 bridge
● Configures port forwarding in
iptables
Routed Strategy
● Creates a pair of veth.
● Moves one to the container
namespace.
● Renames the container veth to
eth0.
● Adds route to 0.0.0.0/0 via
eth0 in container.
● Adds route to container IP via
veth0 in the host.
Docker fork new strategy

OSPF Area
host1% ip route
10.4.5.6 dev veth0
...
Docker* Routed Networking Model
eth0
10.1.2.3/24
veth0
container-A
% ip route
default eth0
10.4.5.6/32
eth0
host2
host3
hostN
switch

Route to 10.1.2.3/32
Infrastructure
Spine
Leaf
Server
10.1.2.3/32
10.1.2.3/32

OSPF: 1998
• Open Shortest Path First
○ Propagated Link State Database
○ Supported by every vendor
• OSPF is computationally expensive
○ On a 1998-style embedded controller: Yes
○ On a 2015-style Intel Atom 64-bit: No
• Everything is point-to-point L3 links
• Switches and Servers run OSPF (Quagga)
• Cumulus! OSPF unnumbered
Old and boring is the new sexy

Running a Container
using the routed strategy
% docker run -it --net=routed --ip-address=10.2.3.4/32 ubuntu
(Will likely change to use labels...)

demo!

bright future ahead!
• Extract networking logic into a reusable library.
• Replace the networking subsystem of Docker.
• Docker 1.7 (libnetwork 0.3)
• Docker 1.8 (libnetwork 1.0)
• Get rid of our patch and wrap it as an extension/plugin.
• https://github.com/docker/libnetwork
LibNetwork

Pros and Cons
Awesomeness Sucksies
IP Mobility
Quick failover
No special snowflakes
Everything in docker
Future: CRIU?
T2 routing limit: 128K entries

How difficult is this?
Welcome to the network revolution!
● 40GbE “white-box” Switches
○ Cumulus: Debian-based Switch OS
○ x86-64 Linux server with 32 network interfaces
● Want to inspect network traffic?
○ sudo apt-get install tcpdump
● Technically possible to run remote xterm on the switch
● Currently waiting for Cumulus to update kernel version
○ Docker on the switches!

Leaf Switch /etc/network/interfaces Server /etc/network/interfaces
auto lo
iface lo inet loopback
address 10.225.10.245/32
%for v in range(1,17):
auto swp${v}
iface swp${v}
mtu 9000
address 10.225.10.${v*8+1}/30
%endfor
%for v in range(17,33):
auto swp${v}
iface swp${v}
mtu 9000
address 10.225.10.245/32
%endfor
auto lo
iface lo inet loopback
auto data0
iface data0 inet static
mtu 9000
address 10.225.10.10
netmask 255.255.255.252
gateway 10.225.10.9
How difficult is the network config?
To Servers
To Spines
To Leaf

Leaf/Spine Switch ospfd.conf Server ospfd.conf
router ospf
ospf router-id 10.225.10.245
network 10.224.0.0/12 area 0.0.0.0
!
interface swp1
ip ospf network point-to-point
!
interface swp2
!
….
! Bootstrap Config
router ospf
ospf router-id 10.225.10.10
redistribute kernel
passive-interface default
no passive-interface data0
network 10.224.0.0/12 area 0.0.0.0
!
log syslog
!
interface data0
!
How difficult is the network config?

“Good enough”
• 24-39 Gbit/s (core affinity)
• 13us ICMP ping
Performance

Local Development With Style
IP Mobility on Local Laptop
Allow for easy and rapid development
Boot2Docker

Boot2Docker on OSX
My MacBook
Boot2Docker VM
10.10.0.0/16
10.10.0.0/16
10.10.2.1/32 frontend on 8080
10.10.2.2/32 backed (date) on 9999
lo0: 10.10.2.2/32
backend
My Shell

Checkout and have fun!
www.github.com/medallia/docker
www.github.com/medallia/boot2docker-iso
docker@medallia.com

Questions?

Jueves 28 de Mayo
http://tinyurl.com/ioextendedba

Microservices using relocatable Docker containers

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