3.5 SDN CloudStack Developer Day By Alex Huang Architect, Cloud Platforms Group, Citrix Systems Inc.

1. Software Defined Networks in
CloudStack
The Vision

2. Multi-site Deployment Architecture
MySQL
Replication Secondary
Mgmt Server
Primary Cluster
MgmtServer
Availability Cluster
Zone 1 Data Center 2
Data Center 1
Availability
Zone 2
Availability Data Center 5
Zone 4
Availability
Zone 5 Availability
Zone 3
Data Center 3
Data Center 4

3. Physical Network within One Availability Zone
Public Internet
Data Firewall / Mgmt Firewall
Load Balancer
Zone-Level Layer 3 Switch Private Network
Pod 1 Pod 2 Pod N
Pod-Level Layer-2 Switch
…
Scale-Out NFS
Computing
Primary
Server 1
Storage
Cluster 2
Computing
Server 2 Primary
Storage
Computing
Server 3
Cluster 1
Primary
Storage
Computing
Server 4

4. Virtual Network overlay
Zone-Level Layer 3 Switch
Public Network Private Network
(65.37.*.*, (192.168.*.*, connections to
billed to users) Mgmt Server)
Pod-Level Layer-2 Switch
65.37.*.* User 1
RServer 1
Computing
Storage
Computing
Server 2 Storage
Computing
Server 3
R
Computing
Server 4
Computing
Server 5
User 2

5. VLAN issues
• Virtual Network isolation (green for Tenant 1 and
red for Tenant 2) realized using VLAN today
– Tenant-specific VLAN can span pods
• Tenant can have multiple isolated virtual networks
to realize multi-tier app
• VLAN = Big Problems
– 4K VLANs = few hundreds of tenants
– All switches have all 4K VLANs provisioned
• See broadcast /multicast even if VLAN is not used.
– Traffic Tromboning across DC
– Cannot stretch multi-tier app across DC

6. AWS VPC
Large-scale production deployment of SDN

7. Open vSwitch (OVS)
• Multi-layer virtual switch supporting
OpenFlow protocol
• High performance production quality
replacement for Linux bridging code
• Default networking stack forXenServer 6.0
onward
• DVS and layer-2 cloud networking supported
via GRE tunnels

8. CloudStack + SDN
• Phase 1 (Demo in ONS/Synergy)
– CloudStack will orchestrate GRE tunnels to replace VLANs
(achieve scale)
– Based on XS 6.0
– CloudStack contains embedded OpenFlow controller (not really,
but something like it)
– Live Migration, Virtual Router, multi-tier apps
• Phase 2:
– KVM support
– NS VPX for LB, NAT
– Multi-hypervisor cloud
– Support External Controllers (BigSwitch)
• BigSwitch will write the integration code
Take this with a grain of salt. Just a vision
statement

9. CloudStack + SDN
• Phase 3
– VXLAN alternative to GRE
• Perhaps NS will have it by then
– NVGRE support
• Phase 4
– AWS VPC semantics and API equivalence