This post is based assumption that KVM as hypervisor, and Openstack is running in Grizzly on top of RHEL6.4.

Openstack VM live migration can have 3 categories:

-Block live migration without shared storage

-Shared storage based live migration

-Volume backed VM live migration

Block live migration

Block live migration does not require shared storage among nova-compute nodes, it uses network(TCP) to copy VM disk from source host to destination host, thus it takes longer time to complete than shared storage based live migration. Also during migration,
host performance will be degraded in network and CPU points of view.

To enable block live migration, we need to change libvirtd and nova.conf configurations on every nova-compute hosts:

->Edit /etc/libvirt/libvirtd.conf

listen_tls = 0

listen_tcp = 1

auth_tcp = "none"

->Edit /etc/sysconfig/libvirtd

LIBVIRTD_ARGS="–listen"

->Restart libvirtd

service libvirtd restart

->Edit /etc/nova/nova.conf, add following line:

live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE

Adding this line is to ask nova-compute to utilize libvirt's true live migration function.

By default Migrations done by the nova-compute does not use libvirt's live migration functionality,
which means guests are suspended before migration and may therefore
experience several minutes of downtime.

>Restart nova-compute service

service openstack-nova-compute restart

->Check running VMs

->Check which host the VM in running on

->Check all available hosts

>Let's migrate the vm to host compute-2

nova live-migration --block-migrate vm-live-migration compute-2

>Later when we check vm status again, we cloud see the host changes to compute-2

>We can just do a migration without specifying destination host, nova-scheduler will choose a free host for you

nova live-migration --block-migrate vm-live-migration

Block live migration seems a good solution if we don't have/want shared storage , but we still want to do some host level maintenance work without bring downtime to running VMs.

Shared storage based live migration

This example we use GlusterFS as shared storage for nova-compute nodes. Since VM disk is stored on shared storage, hence live migration much much more faster than block live migration.

1.Setup GlusterFS cluster for nova-compute nodes

->Prepare 4 nodes, each node has an extra disk other than OS disk, dedicated for GlusterFS cluster

Node 1: 10.68.124.18 /dev/sdb 1TB

Node 2: 10.68.124.19 /dev/sdb 1TB

Node 3: 10.68.124.20 /dev/sdb 1TB

Node 4: 10.68.124.21 /dev/sdb 1TB

->Configure Node 1-4

yum install -y xfsprogs.x86_64

mkfs.xfs -f -i size=512 /dev/sdb

mkdir /brick1

echo "/dev/sdb /brick1 xfs defaults 1 2" >> /etc/fstab 1014 cat /etc/fstab

mount -a && mount

mkdir /brick1/sdb

yum install glusterfs-fuse glusterfs-server

/etc/init.d/glusterd start

chkconfig glusterd on

->On Node-1, add peers

gluster peer probe 10.68.125.19

gluster peer probe 10.68.125.20

gluster peer probe 10.68.125.21

->On node-1, create a volume for nova-compute

gluster volume create nova-gluster-vol replica 2 10.68.125.18:/brick1/sdb 10.68.125.19:/brick1/sdb 10.68.125.20:/brick1/sdb 10.68.125.21:/brick1/sdb

gluster volume start nova-gluster-vol

->We can check the volume information

gluster volume info

Volume Name: nova-gluster-vol

Type: Distributed-Replicate

Status: Started

Number of Bricks: 2 x 2 = 4

Transport-type: tcp

Bricks:

Brick1: 10.68.125.18:/brick1/sdb

Brick2: 10.68.125.19:/brick1/sdb

Brick3: 10.68.125.20:/brick1/sdb

Brick4: 10.68.125.21:/brick1/sdb

->On each nova-compute node, mount the GluserFS volume to /var/lib/nova/instances

yum install glusterfs-fuse

mount.glusterfs 10.68.125.18:/nova-gluster-vol /var/lib/nova/instances

echo "10.68.125.18:/nova-gluster-vol /var/lib/nova/instances glusterfs defaults 1 2" >> /etc/fstab

chown -R nova:nova /var/lib/nova/instances

2.Configure libvirt and nova.conf on every nova-compute node

->Edit /etc/libvirt/libvirtd.conf

listen_tls = 0

listen_tcp = 1

auth_tcp = "none"

->Edit /etc/sysconfig/libvirtd

LIBVIRTD_ARGS="–listen"

->Restart libvirtd

service libvirtd restart

->Edit /etc/nova/nova.conf, add following line:

live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE

3.Let's try live migration

->Check running VMs

->Check which host the VM in running on

->Check all available hosts

>Let's migrate the vm to host compute-2

nova live-migration vm-live-migration compute-2

>Migration should be finished in seconds, let's check vm status again, we cloud see the host changes to compute-2

>We can just do a migration without specifying destination host, nova-scheduler will choose a free host for us

nova live-migration vm-live-migration

3.Volume backed VM live migration

VMs booted from volume can be also easily and quickly migrated just like shared storage based live migration since both cases VM disks are on top of shared storages.

->Create a bootable volume from an existing image

cinder create --image-id --display-name bootable-vol-rhel6.3 5

->Launch a VM from the bootable volume

nova boot --image --flavor m1.medium --block_device_mapping vda=:::0 vm-boot-from-vol

->Check which host the VM is running on

->Do live migration

nova live-migration vm-boot-from-vol

->Check VM status again

VM recovery from failed compute node

If shared storage used, or for VMs booted from volume, we can recovery them if their compute host is failed.

>Launch 1 normal VM and 1 volume backed VM, make they are all running on compute1 node. ( Use live migration if they are not on compute-1)

->Shutdown compute-1 node

[root@compute-1 ~]# shutdown now

->Check VM status

Both VMs get into "SHUTOFF" status.

>Recovery them to compute-2 node

nova evacuate vm-boot-from-vol compute-2 --on-shared-storage

nova evacuate vm-live-migration compute-2 --on-shared-storage

->Check VM status

Both VMs are managed by compute-2 now

-> Reboot 2 VMs

nova reboot vm-boot-from-vol

nova reboot vm-live-migration

-> Check VMs list

Both VMs are back to ACTIVE.

Notes

Currently Openstack has no mechanism to detect host and VM failure and automatically to recover/migrate VM to health host, this reply on 3rd party means to do so

There's also an interesting project named openstack-neat, which is intended to provide an extension to OpenStack implementing dynamic consolidation of Virtual Machines
(VMs) using live migration. The major objective of dynamic VM consolidation is to improve the utilization of physical resources and reduce energy consumption by re-allocating VMs using live migration according to their real-time resource demand and switching
idle hosts to the sleep mode. This really like vSphere DRS function.

Project website: http://openstack-neat.org

http://www.mirantis.com/blog/tutorial-openstack-live-migration-with-kvm-hypervisor-and-nfs-shared-storage/

(http://blog.sina.com.cn/s/blog_6330de3f01019trq.html)

《转》OpenStack Live Migration的更多相关文章

openstack live migration性能分析
http://blog.zhaw.ch/icclab/an-analysis-of-the-performance-of-live-migration-in-openstack/ http://blo ...
OpenStack Live Migration
About live migration of KVM virtual machines with NFS storage, from Mirantis blog: click this link w ...
OpenStack nova VM migration (live and cold) call flow
OpenStack nova compute supports two flavors of Virtual Machine (VM) migration: Cold migration -- mig ...
Migration workstation vms to openstack kvm
Migration workstation vms to openstack kvm 分别分成(磁盘是否拆分,vms 是否有多个磁盘驱动器) 1, linux迁移 vmware workstatio ...
Openstack虚拟机在线迁移(Live Migration)
Openstack VM live migration can have 3 categories: -Block live migration without shared storage -Sha ...
Setting up multi nodes live migration in Openstack Juno with devstack
Setting up multi nodes live migration in Openstack Juno with devstack Summary Live migration overvie ...
migration vmware vms to openstack kvm 修改vmware windows scsi to ide
vmware vms migration to openstack
Converting a VMware Workstation virtual machine to KVM Leave a commentPosted by rbgeek on August 13, ...
VMware migration to openstack kvm

随机推荐

用nohup执行python程序时，print无法输出
python -u参数:关闭输出缓冲 nohup python -u test.py > nohup.out 2>&1 &
ASP.NET MVC 5 学习教程：修改视图和布局页
原文 ASP.NET MVC 5 学习教程:修改视图和布局页起飞网 ASP.NET MVC 5 学习教程目录: 添加控制器添加视图修改视图和布局页控制器传递数据给视图添加模型创建连接字符串 ...
使用webservice实现App与服务器端数据交互
What? webservice曾经认为是解决异构系统间整合的最佳解决方案,不依赖于第三方任何系统的支持(不需要部署RDBMS服务器),大家只需要按照官方的规范,即可完成相互之间的数据交互. Why? ...
【转】关于C语言生成不重复的随机数
一说起随机函数,恐怕又有人说这是老生长谈了……一般很多人都形成了自己的固定格式,因为随机数用处比较大,用的时候比较多,拿过来就用了.但是新手不这么干,他们总是抱有疑惑,我就是一个新手,而且较菜…… ...
JavaScript 中的日期和时间
前言本篇的介绍涵盖以下部分: 1. 时间标准指的是什么?UCT和GMT 的概念.关联和区别? 2. 时间表示标准有哪些? 3. JS 中时间的处理日期时间标准日期的标准就不多说了 -- 公元纪年 ...
arm: 使用结构体操作寄存器
使用结构体操作寄存器: //寄存器赋值和取值的时候,要注意寄存器的长度,有的寄存器的值只有8位. //还要注意,使用volatile修饰寄存器变量.volatile 参考http://www.cnbl ...
java--继承的一些笔记
public class Person { public void display(){ System.out.println("Play Person..."); } stati ...
基于RAF的一个小动画框
RAF也即是requestAnimationFrame,之前的动画都是基于setTimeout写的,所以为了性能方面的考虑,开始使用requestAnimationFrame写动画. function ...
jsp截取字符串
<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn"%> < ...
J2EE基础篇——十三个规范
背景: 1.企业级应用框架的需求,在很多企业级应用中.比如数据库连接.邮件服务.事务处理等都是一些通用企业需求模块,这些模块假设每次在开发中都由开发者来完毕的话,将会造成开发周期长和代码可靠性差等问题 ...

《转》OpenStack Live Migration