kvm虚拟化

虚拟化是云计算的基础。简单的说，虚拟化使得在一台物理的服务器上可以跑多台虚拟机，虚拟机共享物理机的 CPU、内存、IO 硬件资源，但逻辑上虚拟机之间是相互隔离的。

物理机我们一般称为宿主机（Host），宿主机上面的虚拟机称为客户机（Guest）。

那么 Host 是如何将自己的硬件资源虚拟化，并提供给 Guest 使用的呢？
这个主要是通过一个叫做 Hypervisor 的程序实现的。

根据 Hypervisor 的实现方式和所处的位置，虚拟化又分为两种：

全虚拟化：裸金属（没有装操作系统的纯硬件服务器）上部署
优：性能强，工作在真实的服务器的资源里面
缺：不能嵌套

半虚拟化：某一个OS（系统）上部署
缺：比全虚拟化性能低
优：可以嵌套

面向服务器的

kvm
esxi
xen
citrix 银行用的比较多
hyper-v windows上用的多
vmware workstation 面向个人电脑
virualbox 既可以面向个人电脑也可以面向服务器

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 管工具；
• virsh 是我们经常要用的 KVM 命令行工具

部署前请确保你的CPU虚拟化功能已开启。分为两种情况：

• 虚拟机要关机设置CPU虚拟化
• 物理机要在BIOS里开启CPU虚拟化

//关闭防火墙与SELINUX
[root@localhost ~]# systemctl disable --now firewalld.service
[root@localhost ~]# setenforce 0
[root@localhost ~]# reboot 

//安装所需的工具
[root@localhost ~]# yum -y install epel-release vim wget net-tools unzip zip gcc gcc-c++

//验证CPU是否支持KVM；如果结果中有vmx（Intel）或svm(AMD)字样，就说明CPU的支持的
[root@localhost ~]# egrep -o 'vmx|svm' /proc/cpuinfo     //只要是看见了vmx或svm就说明，系统支持虚拟化
vmx

//kvm安装
[root@localhost ~]# yum -y install qemu-kvm qemu-kvm-common qemu-img virt-manager libvirt python3-libvirt libvirt-client virt-install virt-viewer bridge-utils libguestfs-tools

//因为虚拟机中网络，我们一般都是和公司的其他服务器是同一个网段，所以我们需要把 
KVM服务器的网卡配置成桥接模式。这样的话KVM的虚拟机就可以通过该桥接网卡和公司内部 
其他服务器处于同一网段
//此处我的网卡是ens33，所以用br0来桥接ens33网卡
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# ls
ifcfg-ens33
[root@localhost network-scripts]# cp ifcfg-ens33 ifcfg-br0
[root@localhost network-scripts]# cat ifcfg-br0 
TYPE=Bridge
DEVICE=br0
BOOTPROTO=static
NAME=br0
onBOOT=yes
IPADDR=192.168.35.138
NETMASK=255.255.255.0
GATEWAY=192.168.35.2
DNS1=114.114.114.114
DNS2=8.8.8.8
[root@localhost network-scripts]# cat ifcfg-ens33 
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
onBOOT=yes
BRIDGE=br0

//重启网络
[root@localhost network-scripts]# systemctl restart Networkmanager
[root@localhost network-scripts]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33:  mtu 1500 qdisc fq_codel master br0 state UP group default qlen 1000
    link/ether 00:0c:29:b1:e1:b3 brd ff:ff:ff:ff:ff:ff
3: br0:  mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:0c:29:b1:e1:b3 brd ff:ff:ff:ff:ff:ff
    inet 192.168.35.138/24 brd 192.168.35.255 scope global noprefixroute br0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:feb1:e1b3/64 scope link 
       valid_lft forever preferred_lft forever
4: virbr0:  mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:14:58:95 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
5: virbr0-nic:  mtu 1500 qdisc fq_codel master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:14:58:95 brd ff:ff:ff:ff:ff:ff

//启动服务
[root@localhost ~]# systemctl start libvirtd
[root@localhost ~]# systemctl enable libvirtd

//验证安装结果
[root@localhost ~]# lsmod|grep kvm
kvm_intel             311296  0
kvm                   839680  1 kvm_intel
irqbypass              16384  1 kvm

//测试并验证安装结果
[root@localhost ~]# virsh -c qemu:///system list
 Id   名称   状态
-------------------

[root@localhost ~]# virsh --version
6.0.0
[root@localhost ~]# virt-install --version
2.2.1
[root@localhost ~]# ln -s /usr/libexec/qemu-kvm /usr/bin/qemu-kvm
[root@localhost ~]# ll /usr/bin/qemu-kvm
lrwxrwxrwx 1 root root 21 10月 20 16:31 /usr/bin/qemu-kvm -> /usr/libexec/qemu-kvm
[root@localhost ~]# lsmod |grep kvm
kvm_intel             311296  0
kvm                   839680  1 kvm_intel
irqbypass              16384  1 kvm

//查看网桥信息
[root@localhost ~]# brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.000c29b1e1b3       no              ens33
virbr0          8000.525400145895       yes             virbr0-nic

kvm 的 web 管理界面是由 webvirtmgr 程序提供的。

//安装依赖包
[root@localhost ~]# yum -y install git python-pip libvirt-python libxml2-python python-websockify supervisor nginx python-devel

//从github上下载webvirtmgr代码
[root@localhost ~]# cd /usr/local/src/
[root@localhost src]# git clone git://github.com/retspen/webvirtmgr.git
正克隆到 'webvirtmgr'...
remote: Enumerating objects: 5614, done.
remote: Total 5614 (delta 0), reused 0 (delta 0), pack-reused 5614
接收对象中: 100% (5614/5614), 2.97 MiB | 161.00 KiB/s, 完成.
处理 delta 中: 100% (3606/3606), 完成.

//安装webvirtmgr
[root@localhost src]# cd webvirtmgr/
[root@localhost webvirtmgr]# ls
conf                  images       networks          setup.py
console               instance     README.rst        storages
create                interfaces   requirements.txt  templates
deploy                locale       secrets           Vagrantfile
dev-requirements.txt  manage.py    serverlog         vrtManager
hostdetail            MANIFEST.in  servers           webvirtmgr
[root@localhost webvirtmgr]# pip2 install -r requirements.txt

//检查sqlite3是否安装
[root@localhost webvirtmgr]# ln -s /usr/bin/python2 /usr/bin/python
[root@localhost webvirtmgr]# python
Python 2.7.18 (default, Sep 22 2021, 16:02:57) 
[GCC 8.5.0 20210514 (Red Hat 8.5.0-3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlite3    // 如果有输出别的东西就代表有问题
>>> exit()

//初始化帐号信息
[root@localhost webvirtmgr]# python manage.py syncdb
WARNING:root:No local_settings file found.
Creating tables ...
Creating table auth_permission
Creating table auth_group_permissions
Creating table auth_group
Creating table auth_user_groups
Creating table auth_user_user_permissions
Creating table auth_user
Creating table django_content_type
Creating table django_session
Creating table django_site
Creating table servers_compute
Creating table instance_instance
Creating table create_flavor

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       //问你是否创建超级管理员帐号
Username (leave blank to use 'root'): admin       //指定超级管理员帐号用户名，默认留空为root
Email address: 2350233390@qq.com       //设置超级管理员邮箱
Password:         //设置超级管理员密码
Password (again):         //再次输入超级管理员密码
Superuser created successfully.
Installing custom SQL ...
Installing indexes ...
Installed 6 object(s) from 1 fixture(s)

//拷贝web网页至指定目录
[root@localhost webvirtmgr]# mkdir /var/www
[root@localhost webvirtmgr]# cp -r webvirtmgr /var/www/
[root@localhost webvirtmgr]# ls /var/www/
webvirtmgr
[root@localhost src]# chown -R nginx.nginx /var/www/webvirtmgr

//生成密钥
[root@localhost ~]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:PiIUTYAfd5U20ewBR25lOOGc5ywjVOOQOGxdUYH18EA root@localhost.localdomain
The key's randomart image is:
+---[RSA 3072]----+
|   ..... +=XOOE. |
|  . .o. * *OB= = |
|   ..o.o o.oBo. o|
|    ..   . ..+   |
|    .   S . o o  |
|   .   .   . o   |
|    . . o        |
|     . . .       |
|                 |
+----[SHA256]-----+

//由于这里webvirtmgr和kvm服务部署在同一台机器，所以这里本地信任。如果kvm部署在其他机器，那么这个是它的ip
[root@localhost ~]# ssh-copy-id 192.168.35.138
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
The authenticity of host '192.168.35.138 (192.168.35.138)' can't be established.
ECDSA key fingerprint is SHA256:y8UuseADpYv8QEpZIVRu4glCDufNJsCHp1dNWVOpSyQ.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.35.138's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '192.168.35.138'"
and check to make sure that only the key(s) you wanted were added.

//配置端口转发
[root@localhost ~]# ssh 192.168.35.138 -L localhost:8000:localhost:8000 -L localhost:6080:localhost:60
Last login: Wed Oct 20 16:11:01 2021 from 192.168.35.1
[root@localhost ~]# ss -antl
State  Recv-Q Send-Q Local Address:Port  Peer Address:Port Process 
LISTEN 0      128          0.0.0.0:111        0.0.0.0:*            
LISTEN 0      32     192.168.122.1:53         0.0.0.0:*            
LISTEN 0      128          0.0.0.0:22         0.0.0.0:*            
LISTEN 0      128        127.0.0.1:6080       0.0.0.0:*            
LISTEN 0      128        127.0.0.1:8000       0.0.0.0:*            
LISTEN 0      128             [::]:111           [::]:*            
LISTEN 0      128             [::]:22            [::]:*            
LISTEN 0      128            [::1]:6080          [::]:*            
LISTEN 0      128            [::1]:8000          [::]:*    

//配置nginx
## 配置配置文件
[root@localhost ~]#  cd /etc/nginx/
[root@localhost nginx]# ls
conf.d                  koi-utf             scgi_params
default.d               koi-win             scgi_params.default
fastcgi.conf            mime.types          uwsgi_params
fastcgi.conf.default    mime.types.default  uwsgi_params.default
fastcgi_params          nginx.conf          win-utf
fastcgi_params.default  nginx.conf.default
[root@localhost nginx]# cp nginx.conf{,bak}     //把nginx.conf备份一份
[root@localhost nginx]# ls
conf.d                  koi-utf             nginx.conf.default
default.d               koi-win             scgi_params
fastcgi.conf            mime.types          scgi_params.default
fastcgi.conf.default    mime.types.default  uwsgi_params
fastcgi_params          nginx.conf          uwsgi_params.default
fastcgi_params.default  nginx.confbak       win-utf
[root@localhost nginx]# > nginx.conf      // 弃掉这个文件
[root@localhost nginx]# vi nginx.conf     // 直接写
[root@localhost nginx]# cat nginx.conf
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

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;

    include /etc/nginx/conf.d/*.conf;

    server {
        listen       80;
        server_name  localhost;

        include /etc/nginx/default.d/*.conf;

        location / {
            root html;
            index index.html index.htm;
        }

        error_page 404 /404.html;
            location = /40x.html {
        }

        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }
    }
}

## 配置子文件
[root@localhost nginx]# cd conf.d/
[root@localhost conf.d]# ls
[root@localhost conf.d]# vi /etc/nginx/conf.d/webvirtmgr.conf
[root@localhost conf.d]# cat /etc/nginx/conf.d/webvirtmgr.conf
server {
    listen 80 default_server;

    server_name $hostname;
    #access_log /var/log/nginx/webvirtmgr_access_log;

    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;
    }
}

//确保bind绑定的是本机的8000端口
[root@localhost conf]# vi /var/www/webvirtmgr/conf/gunicorn.conf.py
23 bind = '0.0.0.0:8000'        //确保此处绑定的是本机的8000端口，这个在nginx配置中定义了，被代理的端口

//重启nginx
[root@localhost conf.d]# systemctl restart nginx

//设置supervisor
[root@localhost ~]# vim /etc/supervisord.conf 
在文件最后加上以下内容
[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

//启动supervisor并设置开机自启
[root@localhost ~]# systemctl enable --now supervisord
Created symlink from /etc/systemd/system/multi-user.target.wants/supervisord.service to /usr/lib/systemd/system/supervisord.service.

//配置nginx用户
[root@localhost ~]# su - nginx -s /bin/bash
上一次登录：三 10月 20 20:44:57 CST 2021pts/2 上
-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:SYshlaBNJ2l57oUU2a5RjPwxQ9I5nK9bEDfqW0HcJuo nginx@localhost.localdomain
The key's randomart image is:
+---[RSA 2048]----+
|    +==@.+ .     |
|   +++B.# * o    |
|  ..o+.=.% +     |
|     .++Boo      |
|     ..*So .     |
|      o E o      |
|         =       |
|        o        |
|                 |
+----[SHA256]-----+
-bash-4.2$ touch ~/.ssh/config && echo -e "StrictHostKeyChecking=nonUserKnownHostsFile=/dev/null" >> ~/.ssh/config
-bash-4.2$ cat ~/.ssh/config
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
-bash-4.2$ chmod 0600 ~/.ssh/config
-bash-4.2$ ssh-copy-id root@192.168.35.139
/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 '192.168.35.139' (ECDSA) to the list of known hosts.
root@192.168.35.139's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@192.168.35.139'"
and check to make sure that only the key(s) you wanted were added.

-bash-4.2$ exit
登出

[root@localhost ~]# cat /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@localhost ~]# systemctl restart nginx libvirtd