COMMA: Coordinating the Migration of Multi-tier Applications
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Transcript of COMMA: Coordinating the Migration of Multi-tier Applications
COMMA: Coordinating the Migration of Multi-tier ApplicationsJie Zheng, T. S. Eugene Ng, Zhaolei LiuRice UniversityKunwadee SripanidkulchaiNECTEC, Thailand
VEE’14
MotivationLive migration can migrate single
VM efficiently.Existing solutions on migrating
VMs in a multi-tier application can cause serious performance degradation.
Multi-tier Application
Split-components Problem
Existing Solutions
Problem FormulationGiven a set of n VMs in a multi-
tier application.Minimize the performance
degradation, or impact.
◦TM[i,j]: communication traffic rates between VMs prior to the start of migration.
n
i
n
ijji jiTMttimpact
1
,
COMMA“COordinating the Migration of
Multi-tier Applications”◦The first migration coordination
system for multiple VMs.◦Centralized architecture.◦A two-stage scheduling.
Two-stage SchedulingFirst stage: migrates static
content.Second stage : migrate
dynamically generated content.
First StageMigrate VMs in parallel and finish
all VMs’ data migration at the same time.◦The amount of migrated data is
fixed.Adjusts each VM’s migration
speed according to its virtual disk size _SIZETOTAL_DISK
BANDWIDTH*DISK_SIZEivmi
speed
Second StageMigrate dynamically generated
content.◦After the first stage, a set of dirty
blocks are recorded.◦The minimum migration speed of a
VM must be greater than its block dirty rate.
VMs are divided into groups.BANDWIDTH}rateMax_dirty_{ groupvm
ii
Inter-group SchedulingTo minimize the impact.Brute-force
◦O(2n*n!)
Inter-group Scheduling(Cont.)To minimize the impact.Heuristic
◦Repeatedly take the largest rate element (rate, VMi, VMj) from the list L, check if VMi and VMj are already in the group set S. Merge group or insert new groups.
◦Find the permutation of groups in S with minimal impact
◦O(n!)
Intra-group SchedulingStarting the VMs’ migration at
the same time is not an efficient use of available migration bandwidth.
Intra-group Scheduling(Cont.)Estimate the migration time of each
VM.◦Assume the minimal required speed for
each VM is equal to the VM’s maximal dirty rate
“Finish migration at the same time”◦Set different start time to each VM.
Extra available bandwidth will be allocated to the VMs to minimize the total migration time of the group.
Evaluation-SettingSix physical machines.Kernel-based Virtual
Machine(KVM)Multi-tier application: RUBiS
◦Includes web server, application server, database server.
Performance metric: average response time of the request from clients per second.
Migrate 3VMs with different strategies.
Evaluation-Performance
Evaluation-ImpactMigrate 4 VMs from at most three
physical machines to the other three.
Evaluation-EC2Migrate 2 SPECweb2005 VMs
from a university campus network to EC2 instances.
ConclusionPropose COMMA, the first
coordinated live VM migration system for multi-tier applications.◦Based on a two-stage scheduling
algorithm to coordinate the migration of VMs.
◦The goal is to minimize the migration’s impact on inter-component communications.