Dragonflow is an integral project in OpenStack that is designed to help OpenStack networking scale to thousands of compute nodes. It addresses limitations in Neutron's scalability, performance, and operability. Dragonflow uses a lightweight distributed SDN control plane architecture with pluggable database and publish-subscribe drivers. This allows it to distribute network services like DHCP, security groups, and DNAT across compute nodes for improved scalability and performance.

1. Eran Gampel
Gal Sagie
Running Neutron At Scale

2. OpenStack Challenges
• Scalability
• Networking does not scale (<500 compute nodes)
• Performance
• Networking performance is low (namespace overhead, huge
control plane overhead, …)
• Operability
• Reference implementation has lots of maintenance problems (e.g.
thousands of concurrent DHCP servers, namespaces, etc.)

3. Network Node
Compute Node
DHCP
Namespace
Metadata
Proxy
Metdata
Agent
L2
Agent
L3
Agent
OVS
DVR
Namespaces
Linux BridgeLinux BridgeLinux Bridge
RPC
VM
Turning This…
Controller Node

4. Compute Node
Network Node
OVS
VM
Controller Node
Into This
Dragonflow
Controller

5. Dragonflow Highlights
• Integral “Big Tent” project in OpenStack
• Designed to Scale with High Throughput and Low Latency
• Lightweight and Simple
• Easily Extensible
• Distributed SDN Control Plane Architecture
• Focused on advanced networking services
• Distributes Policy Level Abstraction to the Compute Nodes

6. Neutron-Server
Dragonflow
Plugin
DB
OVS
Dragonflow
DB
Driver
Compute Node
OVS
Dragonflow
DB
Driver
Compute Node
OVS
Dragonflow
DB
Driver
Compute Node
OVS
Dragonflow
DB
Driver
Compute Node
DB
VM VM
..
VM VM
..
VM VM
.. VM VM
..
Distributed SDN

7. “Under The Hood”
Compute NodeCompute NodeCompute Node
Dragonflow
Network DB
OVS
Neutron
Server
Redis
OVSDB-Server
ETCD RethinkDBRAMCloud
Kernel Datapath Module
NIC
User Space
Kernel Space
DB Drivers
Redis ETCD RethinkDBRMC
Future
Dragonflow Plugin
Route
Core
API
SG
vswitchd
Container
VM Dragonflow Controller
Abstraction Layer
L2 App L3 App DHCP App
FWaaS LBaaS …FIP/DNAT
Pluggable DB
Layer
NBDBDrivers
SB DB Drivers
SmartNIC OVSDB
ZooKeeper
ETCD
RMC
Redis
OpenFlow
SG App
ZooKeeper
Zookeeper
Pub/Sub Drivers
Redis ØMQ

8. Current Release Features (Mitaka)
L2 core API, IPv4, IPv6
 GRE/VxLAN/STT/Geneve tunneling protocols
Distributed L3 Virtual Router
Distributed DHCP
Pluggable Distributed Database
 ETCD, RethinkDB, RAMCloud, Redis, ZooKeeper
Pluggable Publish-Subscribe
 ØMQ, Redis
Security Groups
 OVS Flows leveraging connection tracking integration
Distributed DNAT
Selective Proactive Distribution
 Tenant Based

9. Pluggable Database Framework
Requirements
HA + Scalability
Different Environments have different requirements
 Performance, Latency, Scalability, etc.
Why Pluggable?
Long time to productize
Mature Open Source alternatives
Allow us to focus on the networking services only

10. Distributed
DB
DB Data 3
DB Data 2
DB Data 1
Full Distribution
Compute Node 1
Dragonflow
Local Cache
OVS
Compute Node N
Dragonflow
OVS
Local Cache
Dragonflow DB Drivers
Redis ETCD ZookeeperRMC
DB Data 3
DB Data 2
DB Data 1
DB Data 3
DB Data 2
DB Data 1

11. Distributed
Database
DB Data 3
DB Data 2
DB Data 1
Selective Distribution
Compute Node 1
Dragonflow
Local Cache
OVS
DB Data 1
Compute Node N
Dragonflow
OVS
Local Cache
DB Data 3
DB Data 2
Dragonflow DB Drivers
Redis ETCD ZookeeperRMC

12. Compute Node
Dragonflow
Local Controller
Subscriber
Redis ØMQ
Compute Node
Dragonflow
Local Controller
Subscriber
Redis ØMQ
Compute Node
Dragonflow
Local Controller
Subscriber
Redis ØMQ
Compute Node
Dragonflow
Local Controller
Subscriber
Redis ØMQ
Neutron Server
Dragonflow
Plugin
Publisher
Redis ØMQ
Neutron Server
Dragonflow
Plugin
Publisher
Redis ØMQ
Neutron Server
Dragonflow
Plugin
Publisher
Redis ØMQ
. . .
DB
. . .
Pluggable Pub/Sub

13. Example
Distributed DHCP
Page 13

14. Network Node
DHCP
namespace
DHCP
namespace
DHCP
namespace
DHCP
namespace
Neutron DHCP Implementation
DHCP
namespace
dnsmasq
DHCP
Agent
Neutron Server
Message Queue
Example
• 100 Tenants
• 3 vNet / tenant
= 300 DHCP Servers

15. 1 VM Send DHCP_DISCOVER
2 Classify Flow as DHCP, Forward to Controller
3 DHCP App sends DHCP_OFFER back to VM
4 VM Send DHCP_REQUEST
5 Classify Flow as DHCP, Forward to Controller
6 DHCP App populates DHCP_OPTIONS from DB/CFG and send
DHCP_ACK
Dragonflow Distributed DHCP
VM DHCP SERVER
1
3
4
6
7
Compute Node
Dragonflow
VM
OVS
VM
1 2
br-int
qvoXXX qvoXXX
OpenFlow
1
4
2
5
7
Dragonflow Controller
Abstraction Layer
L2
App
L3
App
DHCP
App
SG
36
Pluggable DB
Layer
Distributed
DB

16. Roadmap

17. Dragonflow ScalabilityScale
(# Compute
Nodes)
today
10,000
2,500
Time to
Market
n+2
1,000
Dragonflow
& Redis
Dragonflow &
RAMCloud &
ØMQ
Optimized Hybrid
(Reactive/Proactive)
Dragonflow
4,000
n+1soon

18. Roadmap
Additional DB Drivers ZooKeeper, Redis…
Selective Proactive DB
Pluggable Pub/Sub Mechanism
DB Consistency
Distributed DNAT
Security Group
New Applications
Hierarchical Port Binding (SDN ToR) move to ML2
Containers (Kuryr plugin and nested VM support)
Topology Service Injection / Service Chaining
Inter Cloud Connectivity (Border Gateway / L2GW)
Optimize Scale and Performance

19. Rack
ToR
Overlay
Virtual Topology
Underlay
Hardware
DB
Core
RouterODL
Neutron
Server ML2 Mechanism Drivers
ODLDragonflow
Hierarchical Network Management

20. Newton Release New Applications
 IGMP Application
 Distributed Load Balancing (East/West)
 Brute Force prevention
 DNS service
 Distributed Metadata proxy
 Port Fault Detection

21. Dragonflow and Containers

22. Network Services

23. Ride the Dragon!
• Documentation
• https://wiki.openstack.org/wiki/Dragonflow
• Bugs & blueprints
• https://launchpad.net/dragonflow
• DF IRC channel
• #openstack-dragonflow
• Weekly on Monday at 0900 UTC in #openstack-meeting-4
(IRC)