[论文笔记] Dynamic resource management using virtual machine migrations (IEEE Communications Magazine, 2012)

Timespan: 1.29 – 1.30
Mayank Mishra, Anwesha Das, Purushottam Kulkarni, Anirudha Sahoo: Dynamic resource management using virtual machine migrations. IEEE Communications Magazine 50(9): 34-40 (2012) (gs:0)

作者Mayank Mishra于2006年从印度理工学院(IIT)获得硕士学位，之后在思科工作了几年，目前在印度理工学院读博。
这篇是发表在IEEE Communications杂志上的文章，对VM迁移的动机进行了分类，并着重讨论综述了三个问题：迁移时机、迁移对象、迁移目的，此外还比较了Internet环境下与LAN环境下VM迁移的不同点。以下是摘录：

1. 虚拟机迁移的三种方式：suspend-and-copy, pre-copy, post-copy

2. 迁移的目标一般都是为了在满足SLA条件下使资源耗费最小，迁移动机可以分为以下三类：

server consolidation

load balancing

hotspot mitigation

迁移的两种场景 -- load balancing和consolidation（合并）的示意图





3. 迁移时机(When to migrate)

periodic：定期迁移

due to hot spot：热点检测可以分为proactive（主动检测，通过分析VM资源利用的趋势来预测热点以避免发生）和reactive（被动）两种

excess spare capacity

load imbalance

addition/removal of VMs and PMs

4. 迁移对象(Which VM to migrate)

resource constrained VM

holistic(全局的) approach：从全局的角度选择迁移的对象，使得迁移的代价较小

affinity based：比如两个VM通讯非常频繁，那么最好不要把其中一台迁移走

5. 迁移目的(Where to migrate)

depending on available resource capacity

depending on affinity of VMs：比如memory-aware migration

6. 下面是各种迁移目标及对应的策略关系表





7. Internet环境中与LAN环境中迁移的区别

migrating storage：WAN需要传输local disk的数据

network reconfiguration：IP地址会变

为什么需要WAN migration?
原因：比如大型数据中心或企业拥有多个数据中心（可能分布于多个时区），每天需要定时将一些VM迁移到离用户更“近”的位置。另外维护和升级也需要用到WAN migration。

8. 文中提到的一些文献

* 从全局角度选择迁移对象时，目标函数的设计[3-5]
* 不同VM之间的memory share[6]
* gang migration[7]
* 选择合适的迁移目的使得资源耗费最小化[5]

[3] T. Wood et al., “Black-Box and Gray-Box Strategies for Virtual Machine Migration,” Proc. 4th Conf. Symp. Networked Sys. Design & Implementation, 2007.
[4] A. Singh et al., “Server-Storage Virtualization: Integration and Load Balancing in Data centers,” Proc. 2008 ACM/IEEE Conf. Supercomputing, IEEE Press, 2008, pp.1–12.
[5] M. Mishra and A. Sahoo, “On Theory of VM Placement: Anomalies in Existing Methodologies and Their Mitigation Using a Novel Vector Based Approach,” Proc. 4th Int’l. Conf. Cloud Computing, 2011, pp. 275–82.
[6] T. Wood et al., “Memory Buddies: Exploiting Page Sharing for Smart Colocation in Virtualized Data Centers,”Proc. ACM SIGPLAN/SIGOPS Int’l. Conf. Virtual Execution Environments, VEE, 2009, pp. 31–40.
[7] U. Deshpande, X. Wang, and K. Gopalan, “Live Gang Migration of Virtual Machines,” High-Performance Parallel and Distributed Computing, June 2011.