KVM虚拟化

KVM虚拟化

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1、虚拟化介绍

虚拟化是云计算的基础。简单来说，虚拟化使得一台物理服务器上可以跑多台虚拟机，虚拟机共享物理主机的CPU、内存、IO等硬件资源，但是逻辑上虚拟机之间是互相隔阂的。

物理机一般称之为宿主机子，宿主机上面的虚拟机称之为客户机

那么Host是如何将硬件资源虚拟化，并且提供给Guest使用的呢？

这个主要通过一个叫做Hypervisor的来实现的。

• 全虚拟化
• 半虚拟化

全虚拟化：

Hypervisor直接安装在物理机子上，多个虚拟机在Hypervisor运行，其方式一般是一个特殊定制的Linux系统。Xen和VMWare的ESXI都属于这种类型

半虚拟化：

物理机上常见的操作系统，如：windows、Ubuntu等。Hypervisor作为OS上的一个程序模块运行，并且对管理虚拟机管理。KVM、VirtualBox和VMWare Workstation都属于

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2、KVM介绍

kVM 全称是 Kernel-Based Virtual Machine。也就是说 KVM 是基于 Linux 内核实现的。
KVM有一个内核模块叫 kvm.ko，只用于管理虚拟 CPU 和内存。

那 IO 的虚拟化，比如存储和网络设备则是由 Linux 内核与Qemu来实现。

作为一个 Hypervisor，KVM 本身只关注虚拟机调度和内存管理这两个方面。IO 外设的任务交给 Linux 内核和 Qemu。

大家在网上看 KVM 相关文章的时候肯定经常会看到 Libvirt 这个东西。

Libvirt 就是 KVM 的管理工具。

其实，Libvirt 除了能管理 KVM 这种 Hypervisor，还能管理 Xen，VirtualBox 等。

Libvirt 包含 3 个东西：后台 daemon 程序 libvirtd、API 库和命令行工具 virsh

libvirtd是服务程序，接收和处理 API 请求；
API 库使得其他人可以开发基于 Libvirt 的高级工具，比如 virt-manager，这是个图形化的 KVM 管理工具；
virsh 是我们经常要用的 KVM 命令行工具

功能：

基于内核实现虚拟化，KVM包含了一个加载的内核模块kvm.ko。此外，由于KVM对硬件×86架构的依赖，会需要一个处理器规范模块。处理器规范模块与处理器类型相关，如果使用的是Intel的CPU，那么就加载kvm-intel.ko；如果使用的是AMD的CPU，就加载kvm-amd.ko模块。当Linux内核加载KVM模块之后，KVM模块只负责对虚拟机的虚拟CPU、虚拟内存进行管理和调度。

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3、KVM部署

KVM环境准备

系统	IP
redhad	192.168.7.31

如果为虚拟机

部署前需要开启虚拟化功能

关闭防火墙和selinux

#关闭防火墙
[root@kvm ~]# systemctl stop firewalld 
[root@kvm ~]# systemctl disable firewalld
[root@kvm ~]# setenforce 0 
[root@kvm ~]# sed -ri 's/^(SELINUX=).*/1disabled/g' /etc/selinux/config 
[root@kvm ~]# reboot

配置网络源

[root@kvm yum.repos.d]# curl -o /etc/yum.repos.d/CentOS7-Base-163.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo 
[root@kvm ~]# sed -i 's/$releasever/7/g' /etc/yum.repos.d/CentOS7-Base-163.repo 
[root@kvm ~]# sed -i 's/^enabled=.*/enabled=1/g' /etc/yum.repos.d/CentOS7-Ba se-163.repo 

安装KVM和一些依赖

[root@kvm ~]# yum -y install epel-release vim wget net-tools unzip zip gcc gcc-c++
#验证CPU是否支持KVM
[root@kvm ~]# egrep -o 'vmx|svm' /proc/cpuinfo 
vmx
vmx
#安装KVM
[root@kvm ~]# yum -y install qemu-kvm qemu-kvm-tools qemu-img virt-manager libvirt libvirt-python libvirt-client virt-install virt-viewer bridge-utils libguestfs-tools 
#如果为桥接网络，则需要配置网卡。否则直接跳过
[root@kvm ~]# cd /etc/sysconfig/network-scripts/ 
[root@kvm network-scripts]# ls ifcfg-ens33  ifdown-isdn      ifup          ifup-plip      ifup-tunnel ifcfg-lo     ifdown-post      ifup-aliases  ifup-plusb     
[root@kvm network-scripts]# cp ifcfg-ens33 ifcfg-br0 
[root@kvm network-scripts]# cat ifcfg-br0
[root@kvm network-scripts]# cat ifcfg-br0
TYPE=Bridge 
DEVICE=br0 
NM_CONTROLLED=no 
BOOTPROTO=static 
NAME=br0 ONBOOT=yes 
IPADDR=192.168.7.31
NETMASK=255.255.255.0 
GATEWAY=192.168.7.1 
DNS1=114.114.114.114 
DNS2=8.8.8.8 
[root@kvm network-scripts]# cat ifcfg-ens33 
TYPE=Ethernet 
BOOTPROTO=static 
NAME=ens33 
DEVICE=ens33 
ONBOOT=yes 
BRIDGE=br0 
NM_CONTROLLED=no
[root@kvm ~]# systemctl restart network 
#我用的是非桥接网络
[root@kvm ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.7.31  netmask 255.255.255.0  broadcast 192.168.7.255
        inet6 fe80::20c:29ff:fe83:acfa  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:83:ac:fa  txqueuelen 1000  (Ethernet)
        RX packets 3035131  bytes 4249280965 (3.9 GiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 194612  bytes 35114690 (33.4 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1  (Local Loopback)
        RX packets 151327  bytes 34617483 (33.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 151327  bytes 34617483 (33.0 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:0d:4e:ad  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@kvm ~]# 
#启动服务
[root@kvm ~]# systemctl start libvirtd 
[root@kvm ~]# systemctl enable libvirtd
#验证
[root@kvm ~]# lsmod|grep kvm kvm_intel
170086  0 kvm                   566340  
1 kvm_intel irqbypass              13503  1 kvm

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4、KVM的web控制端安装

#安装依赖
[root@kvm ~]# yum -y install git python-pip libvirt-python libxml2-python python-websockify supervisor nginx python-devel
#升级pip
[root@kvm ~]# pip install --upgrade pip -i http://mirrors.aliyun.com/pypi/simple/ --trusted-host mirrors.aliyun.com
#从github上面下载webvirtmgr代码
[root@kvm ~]# cd /usr/local/src/ 
[root@kvm src]# git clone git://github.com/retspen/webvirtmgr.git 
#安装webvirtmgr
[root@kvm src]# cd webvirtmgr/
[root@kvm webvirtmgr]# pip install -r requirements.txt -i http://mirrors.aliyun.com/pypi/simple/ --trusted-host mirrors.aliyun.com
#初始化账号信息
[root@kvm webvirtmgr]# python manage.py syncdb
........省略......
You just installed Django's auth system, which means you don't have any superusers defined.
Would you like to create one now? (yes/no): yes
#用户默认root直接回车
Username (leave blank to use 'root'): 
Error: Enter a valid email address.
#邮箱
Email address: 1956104705@qq.com
#设置web端的登录密码
Password: 
Password (again): 
Error: Your passwords didn't match.
Password: 
Password (again): 
Superuser created successfully.
Installing custom SQL ...
Installing indexes ...
Installed 6 object(s) from 1 fixture(s)
#拷贝web网页到指定/var/www下
[root@kvm webvirtmgr]# mkdir /var/www 
[root@kvm webvirtmgr]# cp -r /usr/local/src/webvirtmgr /var/www/ 
[root@kvm webvirtmgr]# chown -R nginx.nginx /var/www/webvirtmgr/
#生成密钥
[root@kvm ~]# ssh-keygen -t rsa 
...省略......
[root@kvm ~]# ssh-copy-id 192.168.7.31
#配置端口转发
[root@kvm ~]# ssh 192.168.7.31 -L localhost:8000:localhost:8000 -L localh 
#配置nginx
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
# Load dynamic modules. See /usr/share/doc/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  /var/log/nginx/access.log  main;
    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
 keepalive_timeout   65;
    types_hash_max_size 2048;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;
    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;
    server {
        listen       80;
        server_name  localhost;
        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;
        location / {
        }
        error_page 404 /404.html;
            location = /40x.html {
        }
#配置代理
[root@kvm ~]# vim /etc/nginx/conf.d/webvirtmgr.conf 
server {
    listen 80 default_server;
    server_name $hostname;
    location /static/ {
        root /var/www/webvirtmgr/webvirtmgr;
        expires max;
    }
    location / {
        proxy_pass http://127.0.0.1:8000;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-for $proxy_add_x_forwarded_for;
        proxy_set_header Host $host:$server_port;
        proxy_set_header X-Forwarded-Proto $remote_addr;
        proxy_connect_timeout 600;
        proxy_read_timeout 600;
        proxy_send_timeout 600;
        client_max_body_size 1024M;
    }
 }
 #绑定端口为8000
[root@kvm ~]# vim /var/www/webvirtmgr/conf/gunicorn.conf.py 
....
bind = '0.0.0.0:8000' 
....
[root@kvm ~]# systemctl restart nginx 
#设置supervisord
[root@kvm ~]# vim /etc/supervisord.conf 
#尾行添加
[program:webvirtmgr]
command=/usr/bin/python2 /var/www/webvirtmgr/manage.py run_gunicorn -c /var/www/webvirtmgr/conf/gunicorn.conf.py
directory=/var/www/webvirtmgr
autostart=true
autorestart=true
logfile=/var/log/supervisor/webvirtmgr.log
log_stderr=true
user=nginx
[program:webvirtmgr-console]
command=/usr/bin/python2 /var/www/webvirtmgr/console/webvirtmgr-console
directory=/var/www/webvirtmgr
autostart=true
autorestart=true
stdout_logfile=/var/log/supervisor/webvirtmgr-console.log
redirect_stderr=true
user=nginx
[root@kvm ~]# systemctl start supervisord 
[root@kvm ~]# systemctl enable supervisord 
#配置nginx用户
[root@kvm ~]#  su - nginx -s /bin/bash
-bash-4.2$  ssh-keygen -t rsa 
Generating public/private rsa key pair.
Enter file in which to save the key (/var/lib/nginx/.ssh/id_rsa): 
Created directory '/var/lib/nginx/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /var/lib/nginx/.ssh/id_rsa.
Your public key has been saved in /var/lib/nginx/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:e+4AmfxrFND7ACL3VEGH2KEajgulSJur5HULbcFerGw nginx@kvm-web
The key's randomart image is:
+---[RSA 2048]----+
|       *=+.      |
|  . o =.+.       |
| ..o.+.o .       |
|oooo.+oo+        |
|+o. oo=oS+       |
| ...+ +o...      |
| o.o E .+ .      |
|+ . = . .=       |
|..   . ...o      |
+----[SHA256]-----+
-bash-4.2$ 
-bash-4.2$  touch ~/.ssh/config && echo -e "StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null" >> ~/.ssh/config
-bash-4.2$  chmod 0600 ~/.ssh/config
-bash-4.2$  ssh-copy-id root@192.168.7.31
/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/var/lib/nginx/.ssh/id_rsa.pub"
/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
Warning: Permanently added '192.168.7.31' (ECDSA) to the list of known hosts.
root@192.168.7.31's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@192.168.7.31'"
and check to make sure that only the key(s) you wanted were added.

-bash-4.2$ exit

[root@kvm ~]#  vim /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla
[Remote libvirt SSH access]
Identity=unix-user:root
Action=org.libvirt.unix.manage
ResultAny=yes
ResultInactive=yes
ResultActive=yes
[root@kvm ~]#  chown -R root.root /etc/polkit-1/localauthority/50-local.d/50libvirt-remote-access.p^Ca[root@kvm-web ~]# -local.d/50libvirt-remote-access.
[root@kvm ~]#  chown -R root.root /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla 
[root@kvm ~]#  systemctl restart nginx 
[root@kvm ~]#  systemctl enable nginx 
Created symlink from /etc/systemd/system/multi-user.target.wants/nginx.service to /usr/lib/systemd/system/nginx.service.
[root@kvm ~]# systemctl restart libvirtd
[root@kvm ~]# ss -antl
State       Recv-Q Send-Q               Local Address:Port                              Peer Address:Port              
LISTEN      0      128                              *:111                                          *:*                  
LISTEN      0      128                              *:80                                           *:*                  
LISTEN      0      5                    192.168.122.1:53                                           *:*                  
LISTEN      0      128                              *:22                                           *:*                  
LISTEN      0      100                      127.0.0.1:25                                           *:*                  
LISTEN      0      128                      127.0.0.1:6010                                         *:*                  
LISTEN      0      100                              *:6080                                         *:*                  
LISTEN      0      128                              *:8000                                         *:*                  
LISTEN      0      128                             :::111                                         :::*                  
LISTEN      0      128                             :::22                                          :::*                  
LISTEN      0      100                            ::1:25                                          :::*                  
LISTEN      0      128                            ::1:6010                                        :::*                  
[root@kvm ~]# 

web界面效果

访问：http://192.168.7.31/login

后续操作：请见第二篇