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 Workshop on Management of Cloud Systems ( Workshop on Management of Cloud Systems (MoCS MoCS 2011) MoCS 2011) 2011) 2011) ���������� �� ���������� �� ������ ������ ������������� ������������� ��������������� ��������������� �������� �������� ������� ������� ���������������� �������� �������� �������������� �������� ������ 1
Datacenters Datacenters for for Cloud Cloud Computing Computing � Large infrastructures to take advantage of scale economies; � Platform virtualization to flexibly consolidate the computing workload; workload; � Highly dynamic virtual infrastructures; � Infrastructure sharing among different users; 2
Platform Virtualization Platform Virtualization � 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 � Virtual Machines Monitors are able to manage VMs life cycle. Typical “ virtualization primitives ” are: � Start / Stop / Restart � Pause / Resume � Live migration 3
Live Live migration migration of of 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 � There is shared storage between source and destination VMMs; � source and destination VMMs both reside in the same LAN. 4
Datacenters Datacenters Networking Networking � Large numbers of connected devices; � Huge aggregated � Huge aggregated communication requirements; � Hierarchical design; � Three levels of network: Access , Aggregation , Core 5
Datacenters Datacenters Networking Networking : : strategies strategies (1/2) (1/2) � L3/L2 � L2 � L2 � L2 � Scalability issues: � Too large broadcast domains � Spanning tree protocol convergence time 6
Datacenters Datacenters Networking Networking : : strategies strategies (2/ (2/2 2) � L3 � L3 � L3 � L3/L2 � Advantages: � Faster routing convergence; � Simplified troubleshooting and management procedure 7
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: � Mobile IP model; � Network Address Translation (NAT) � Totally transparent 8
Live Live migration migration among among different different IP IP subnets subnets: overview overview � 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 � 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 ; 9
Terminology Terminology (1/2) (1/2) � Home Network : the original VM’s network � Foreign Network : the network where the VM is migrated � 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 10
Terminology Terminology 2/ 2/2 Home Network Care-of Address Care-of Address Foreign Network Home Address � 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 11
IP IP address address migration migration (1/5) (1/5) � Packets follow classical routing rules 12
IP IP address address migration migration (2/5) (2/5) � Migration process starts � Packets continue to follow the original route 13
IP address IP address migration migration: : solution solution (3/5) (3/5) � The CoA is assigned to the VM � � � � � ��������� ��������� � � � � � ������� ��������� ���������� �� ������� �� � �� � �� �� ������� ������� ����������� ����������� �� �� � � � � � �� �� � ������� ������� M* 14
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 � Packets route is not optimized 15
IP IP address address migration migration: : optimized optimized solution solution (5/ (5/5) � NAT rules to the Edge Service Switch are added � Packets are redirected to the new VM location location 16
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 � Gratuitous ARP are used to minimize the network downtime 17
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 � Gratuitous ARP – to reduce the network downtime 18
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 � ICMP redirect to optimize communications 19
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) Migrated (IP mobile-like) 3.192 3.192 Migrated (optimized) 2.034 Web Server test Mean Response Time (ms) Non migrated 3.4 Migrated (optimized) 3.1 20
Conclusions Conclusions � Live migration is an useful tool for modern Cloud oriented datacenters: IP address migration removes a limitation on the application of such tool; � With the exclusion of the FN, no packets with “strange” IP � 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; 21
Future Future works works � Performance evaluation: � network performance of migrated VMs � Impact of several migrations on the datacenter’s routing � 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) 22
Thank Thank you you!! !! 23
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