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Transparent migration of virtual Transparent migration of virtual infrastructures in large datacenters for infrastructures in large datacenters for Cloud Computing Cloud Computing

Workshop on Management of Cloud Systems ( Workshop on Management of Cloud Systems (MoCS MoCS 2011) 2011)

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Workshop on Management of Cloud Systems ( Workshop on Management of Cloud Systems (MoCS MoCS 2011) 2011)

Datacenters Datacenters for for Cloud Cloud Computing Computing

Large infrastructures to take advantage of scale economies; Platform virtualization to flexibly consolidate the computing workload;

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workload; Highly dynamic virtual infrastructures; Infrastructure sharing among different users;

Enables the multiplexing of resources by creating several Virtual Machines on top of a single physical server; Decouples Virtual Machines from underlying hardware; Virtual Machines Monitors are able to manage VMs life

Platform Platform Virtualization Virtualization

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Virtual Machines Monitors are able to manage VMs life

• cycle. Typical “virtualization primitives” are:

Start / Stop / Restart Pause / Resume Live migration

Live Live migration migration of

• f Virtual

Virtual Machines Machines

Live migration allows Cloud Providers to dynamically reconfigure the allocation of VMs over the available physical resources; Live migration process typically assumes that:

There is shared storage between source and destination

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There is shared storage between source and destination VMMs; source and destination VMMs both reside in the same LAN.

Datacenters Datacenters Networking Networking

Large numbers of connected devices; Huge aggregated

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Huge aggregated communication requirements; Hierarchical design; Three levels of network: Access, Aggregation, Core

Datacenters Datacenters Networking Networking : : strategies strategies (1/2) (1/2)

L3/L2 L2

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L2 L2 Scalability issues: Too large broadcast domains Spanning tree protocol convergence time

Datacenters Datacenters Networking Networking : : strategies strategies (2/ (2/2 2)

L3 L3

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L3 L3/L2 Advantages: Faster routing convergence; Simplified troubleshooting and management procedure

Live Live migration migration among among different different IP IP subnets subnets

Based on a modification of the Service Switching paradigm ( V. Manetti, R. Canonico, G. Ventre, and I. Stavrakakis, “System-

Level Virtualization and Mobile IP to Support Service Mobility” )

Combines:

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Mobile IP model; Network Address Translation (NAT)

Totally transparent

A new IP Address (the Care-of Address) is assigned to a migrated VM; The CoA is used to find the new location of the migrated

Live Live migration migration among among different different IP IP subnets subnets:

• verview
• verview

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The CoA is used to find the new location of the migrated VM; The VM’s operating system is unaware of the CoA; Packets are delivered to the VM through standard routing;

Terminology Terminology (1/2) (1/2)

Home Network: the original VM’s network Foreign Network: the network where the VM is migrated

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Home Address: the original VM’s address (a Home Network’s address) Care-of Address: the IP address assigned to the VM on the Foreign Network

Terminology Terminology 2/ 2/2

Home Network Care-of Address

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Service Switch: a router that supports IP addresses migrations

Home: the service switch connected to the HN Foreign: the service switch connected to the FN Edge: the service switch that resides at the edge of the datacenter

Foreign Network Home Address Care-of Address

IP IP address address migration migration (1/5) (1/5)

Packets follow classical routing rules

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IP IP address address migration migration (2/5) (2/5)

Migration process starts Packets continue to follow the original route

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IP IP address address migration migration: : solution solution (3/5) (3/5)

The CoA is assigned to the VM

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• M*

IP IP address address migration migration: IP : IP mobile mobile-like like approach approach (4/5) (4/5)

Involves two service switches Dirrent routes when migrated VM sends or receives packets Packets route is not

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Packets route is not

• ptimized

IP IP address address migration migration: : optimized

• ptimized solution

solution (5/ (5/5)

NAT rules to the Edge Service Switch are added Packets are redirected to the new VM location

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location

Problems Problems 1/3 ( 1/3 (Migrated Migrated VM VM perspective perspective)

Migrated VM’s default gateway is unchanged; Migrated VM tries to send packets to HN’s nodes directly;

Foreign Service Switch acts as ARP Proxy for the Home Network Gratuitous ARP are used to minimize the network

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Gratuitous ARP are used to minimize the network downtime

Problems Problems 2/3 (Home network’s 2/3 (Home network’s node node perspective perspective)

Migrated VM’s IP address doesn’t reside on the Home Network anymore

Home Service Switch acts as ARP Proxy for the Home Address Gratuitous ARP – to reduce the network downtime

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Gratuitous ARP – to reduce the network downtime

Problems Problems 3/ 3/3 (Foreign Foreign network’s network’s nodes nodes perspective perspective)

Migrated VM’s IP address does not reside on the Home Network anymore

Foreign Service Switch knows the new location of the migrated VM ICMP redirect to optimize communications

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ICMP redirect to optimize communications

Live Live migration migration among among different different IP IP subnets subnets: : validation validation experiment experiment

Ping test Mean RTT (ms) Non migrated 2.573 Migrated (IP mobile-like) 3.192

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Migrated (IP mobile-like) 3.192 Migrated (optimized) 2.034

Web Server test Mean Response Time (ms) Non migrated 3.4 Migrated (optimized) 3.1

Conclusions Conclusions

Live migration is an useful tool for modern Cloud oriented datacenters: IP address migration removes a limitation

• n the application of such tool;

With the exclusion of the FN, no packets with “strange” IP

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With the exclusion of the FN, no packets with “strange” IP addresses traverse the datacenter’s network. To successfully provide IP address migrations, the datacenter networking topology must be known by the datacenter/virtualization management tools;

Future Future works works

Performance evaluation:

network performance of migrated VMs

Impact of several migrations on the datacenter’s routing

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Impact of several migrations on the datacenter’s routing Integration in opensource cloud computing/virtualization management software (e.g., OpenNebula, CLEVER) Alternative implementations (e.g., OpenFlow-based)

Thank Thank you you!! !!

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