The document summarizes CloudStack architecture plans for the future. It discusses moving to management server clusters per availability zone rather than per region. It also discusses using an object storage system for templates and snapshots rather than a separate NFS server. Finally, it discusses a possible future model where CloudStack manages existing virtualization clusters rather than deploying and managing its own system VMs.

1. CloudStack Architecture Future
Sheng Liang, CTO Cloud Platforms, Citrix Systems
July 21, 2012

2. Users
SS CP Cloud
VR EC2
Stack API Layer
VM VM
Access control
System VM
Framework Orchestration Plug-in
Engine Framework
Event Framework
Resource Management
Plug-ins
Message Bus (for storage,
vSphere XenServer KVM SRX NetScaler Other networking,
Resource Resource Resource Resource Resource Resources hypervisor,
etc.)

3. Future: CloudStack storage
CloudStack
Primary Storage Mgmt Server
• Can be configured zone-wide
• Supports true EBS implementations
AWS-style AWS-style AWS-style
Availability Availability Availability
Zone Zone Zone
Secondary Storage
• No longer needed zone-wide NFS server Object Storage
• Region-wide object store for templates, ISOs
and snapshots
• Templates and ISOs cached in Primary Storage

4. • Apache Foundation project
• Hadoop Core includes:
ᵒ HDFS - Distributed file system derived from Google File System
ᵒ Map/Reduce – Distributed compute engine
• Written in Java
• Runs on Linux, Mac OS/X, Windows, and Solaris
• Optimized for commodity hardware

5. Now: management server clusters, zones, and regions
Region 1 Region 2
Data Data Data Data Data Data
Center Center Center Center Center Center
Primary Standby Primary Standby
Mgmt Mgmt Mgmt Mgmt
Server Server Server DR Server
Cluster
DR Cluster Cluster Cluster
Availability Availability Availability Availability Availability Availability
Zone Zone Zone Zone Zone Zone
Object Storage Object Storage

6. Future: management server cluster per zone
Region 1 Region 2
Data Data Data Data Data Data
Center Center Center Center Center Center
Mgmt Mgmt Mgmt Mgmt Mgmt Mgmt
Server Server Server Server Server Server
Cluster Cluster Cluster Cluster Cluster Cluster
Availability Availability Availability Availability Availability Availability
Zone Zone Zone Zone Zone Zone
Object Storage Object Storage

7. • Implement rigorous state machines for all operations
• Customizable workflow engine
• Enhance plug-in framework
ᵒ Storage plug-in

8. • Stateless, recreatable, and restartable
• CloudStack manages auto-scaling of System VMs
• System VMs may be dedicated (e.g., virtual router) or shared (SSVM
and CPVM)
• Potentially expose System VM framework to 3rd-party VMs?
ᵒ NetScaler VPX
ᵒ User VM

9. S3 API
NFS, CIFS, HDFS,
3rd-Party Object
S3 API VM Store API, …
S3 API VM Object Store
… … … (e.g., NetApp, Hadoop, Cloudian)
S3 API VM
CloudStack Compute Nodes

10. • Clean up access control code
• API servers run as a separate service
ᵒ Running in System VM

11. • Built on message bus
• Treats management server DB as the desired state
• Some downsides:
ᵒ Prevents use of native virt mgmt tools
ᵒ Bugs could cause disastrous results (like stopping/destroying guest VMs)
• An alternative model: CloudStack functions as a virt admin user,
enabling super admin to use native virt mgmt tools

12. Future model
Userh CloudStack
Mgmt Server
vCenter ESXi Cluster
vCenter
Client
Admin XenServer
Cluster
XenCenter
Hyper-V
Systems
Cluster
Center

13. • Register existing virt clusters
• CloudStack must assume any of the underlying networks, storage,
hosts, and VMs can change state any time
• Expose additional virt mgmt capabilities as cloud API

14. Manage existing server virt clusters
CloudStack Region
AWS-style AWS-style AWS-style Existing Existing
Availability Availability Availability Server Virt Server Virt
Zone Zone Zone Clusters Clusters
Object Storage

15. Work better. Live better.