1. Elastic Provisioning In Virtual Private Clouds
Prashant Shenoy
University of Massachusetts Amherst
*Joint work with Tim Wood, K.K Ramakrishnan and
Kobus Van Der Merwe

2. Cloud Computing Cloud Platform Enterprise Sites Cloud Platform types:
Software as a Service
Hotmail, Google Docs
Platform as a Service
Google App Engine, Microsoft Azure
Infrastructure as a Service
Amazon EC2, VMware vCloud
Rent computation and storage resources on demand
Accessed by multiple enterprise sites
Cloud Platform
Enterprise Sites

3. Enterprise Cloud Challenges
Existing cloud platforms do not meet the needs of enterprise customers
Insufficient security controls
Need isolation at server and network level
Deployment is difficult
Cloud resources are completely separate from local ones
Can’t make VMs look like part of existing LAN
Limited control over network resources
Cannot specify network topology or IP addresses
Cannot reserve bandwidth for network links
Inadequate support for Cross-Data center Management

4. Moving to the Cloud Acme LAN Front End Reports Processing Tier
Acme wants to move part of its payroll app into the cloud
Acme LAN
Front End Reports
Processing Tier
Data Store
Cloud Platform
Processing Tier

5. Problem #1: Transparency
Application may have been written for LAN environment
Might utilize broadcast or LAN service discovery
Must add Internet gateways for apps previously only on LAN
Now must communicate via public IPs or configure DNS
Lack of transparency causes application modifications and infrastructure reconfigurations
Acme LAN
Front End
Cloud Platform GW
front.acme.com
Processing proc.cloud.com
Data Store GW
data.acme.com

6. Processing proc.cloud.com
Problem #2: Security
Acme’s servers are now accessible from the public internet!
Servers formerly on secure LAN now exposed to malicious users
Must configure firewall rules to limit access
Fine grain rules are difficult to manage in dynamic environments
Lack of secure cloud connections exposes enterprise to threats from both in and out of the cloud
Acme LAN
Front End
front.acme.com
Cloud Platform
Processing proc.cloud.com
Data Store
data.acme.com
Hacker123 hax.cloud.com

7. Problem #3: Flexible Resource Mgmt
Benefit of cloud computing: ability to easily adjust resource capacities and add new VMs
After a change must deal with transparency and security issues all over again!
Current platforms do not support network resource reservation (Bandwidth/QoS guarantees)
Enterprises want control over network resources. Cloud must support dynamic changes
Acme LAN
Front End
front.acme.com
Cloud Platform +1
Processing proc.cloud.com +1
Data Store
data.acme.com +1
Processing #2 proc2.cloud.com

8. Problem #4: Cross Data Center Management
Enterprise IT services spread across in-house and cloud data centers. May be spread across multiple cloud sites Need the ability to flexibly manage, provision and optimize across data centers Follow-the-sun, energy optimizations, Current platforms: Limited support for cross-data center optimizations

9. Key Observation
Existing cloud platforms only cover storage and computation
Cloud Platform
Enterprise Sites
Disk VM + +
Enterprise Clouds need control over the network as well

10. Virtual Private Clouds
A Virtual Private Cloud is…
A secure collection of server, storage, and network resources spanning one or more cloud data centers
That is seamlessly connected to one or more enterprise sites
Virtual Private Networks (VPNs)
Layer 2 and 3 MPLS based VPNs
Created by network provider with no end host configuration
Already used by many businesses! VM VM
Cloud
Sites
Enterprise
Sites VM VM

11. VPC Benefits For the customer: Isolates network & compute resources
Cloud resources are only accessible through VPN
Simplifies deployment since cloud looks same as local resources
Unifies resource pools across cloud/data center sites
For the service provider:
Provides mechanism for control over resource reservation within provider network
Simplifies management of multiple data centers by combining them into large resource pools

12. VPC Challenges & Solutions
Existing cloud platforms do not integrate with network service providers
Must coordinate with ISP to create VPN endpoints
VPN endpoints must be linked to VLANs within the cloud data center
VPN endpoints are traditionally static
Utilize virtual routers with programmable interfaces to rapidly create and reconfigure routers
Use BGP signaling to dynamically adjust VPN topology

13. CloudNet Cloud Manager Allocates computation and storage resources
Manages VLAN assignment within cloud network
Network Manager
Creates and configure VPN endpoints
Reserves network resources
Routers
Customer Edge
Provider Edge
Network Manager
Cloud Manager
Here I explain the basic components of cloudnet and give some more details about what support you would need to add to a system like amazon ec2 to make this work (interface with ISP to control VPN setup at PE routers / connection to VLANs within cloud site) VM VM
VPN
VLAN
VPN
VLAN VM VM

14. WAN Migration
Change the scale of provisioning from managing servers on a rack to managing resources across data centers
Key building block: ability to migrate applications across data centers
Existing approach: LAN-based VM migration
VPC enable VM migration over WAN!

15. Can use existing LAN migration techniques to move across WAN
WAN Migration
Layer 2 VPNs make WAN act like a LAN
Can use existing LAN migration techniques to move across WAN

16. Can use existing LAN migration techniques to move across WAN
WAN Migration
Layer 2 VPNs make WAN act like a LAN CE
Cloud Site 1
Customer Site A B PE PE
VLAN
ARP!
Layer 2 VPN (VPLS) CE
Router
ARP! PE
Switch B
VLAN
Cloud Site 2
VPN endpoint
Can use existing LAN migration techniques to move across WAN

17. WAN Migration Challenges
Performance over WAN is problematic Lower bandwidth and higher latencies imply longer migration/pause times Storage may or may not be shared will need to migrate storage as well

18. CloudNet WAN Migration
Once connectivity is setup, migration requires
Storage Migration
Live Memory Migration
Storage Migration is done through a combination of
Asynchronous Copy of disk storage to remote site initially
Synchronous copy of incremental updates subsequently during live memory migration
Live Memory Migration needs to balance multiple needs
Total Migration Time for live memory (reduced application performance)
Pause Time (application has to be quiescent for final transfer)
Amount of Data Transfer (Bandwidth Requirement)

19. Optimizations WAN optimizations
Dynamic Stop and Copy
Content Based Redundancy
Incremental updates (page deltas)
Overall benefit is significant reduction in migration and pause times, especially for limited bandwidth between sites
Preliminary results:
65% data reduction, 3x reduction in migration times across data centers in Texas and Illinois

20. Performance of CloudNet Live Migration over WANs
Kernel
SpecJBB
TPC-W

21. Summary Cloud Computing for enterprises requires: Security
Transparency
Flexibility
CloudNet can help provide these features
Defines interface between cloud platform and network provider
Uses VPNs for secure, seamless connections
Employs virtualization at server, router, and network levels to improve agility and efficiency
Implements optimizations to reduce latency of WAN migration
Future work : “DR on a Cloud”
Utilize VPLS to simplify deployment of high availability services across WAN

22. More at http://lass.cs.umass.edu
Questions?
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