一、虚拟化介绍
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
- 半虚拟化
全虚拟化：
Hypervisor 直接安装在物理机上，多个虚拟机在 Hypervisor 上运行。Hypervisor 实现方式一般是一个特殊定制的 Linux 系统。Xen 和 VMWare 的 ESXi 都属于这个类型
半虚拟化：
物理机上首先安装常规的操作系统，比如 Redhat、Ubuntu 和 Windows。Hypervisor 作为 OS 上的一个程序模块运行，并对管理虚拟机进行管理。KVM、VirtualBox 和 VMWare Workstation 都属于这个类型
理论上讲：
全虚拟化一般对硬件虚拟化功能进行了特别优化，性能上比半虚拟化要高；
半虚拟化因为基于普通的操作系统，会比较灵活，比如支持虚拟机嵌套。嵌套意味着可以在KVM虚拟机中再运行KVM。
二、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
三、kvm部署
环境说明
| 系统类型 | IP | 职责 |
|---|---|---|
| centos8 | 192.168.91.137 | KVM |
| centos7 | 192.168.91.140 | KVM-web |
kvm安装（centos8）
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
准备工作
// 关闭防火墙和selinux
[root@centos8 ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@centos8 ~]# vi /etc/selinux/config
SELINUX=disabled
[root@centos8 ~]# reboot
[root@centos8 ~]# setenforce 0
setenforce: SELinux is disabled
[root@centos7 ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@centos7 ~]# vi /etc/selinux/config
SELINUX=disabled
[root@centos7 ~]# reboot
[root@centos7 ~]# setenforce 0
setenforce: SELinux is disabled
下载工具包
[root@centos8 ~]# dnf -y install epel-release vim wget net-tools unzip zip gcc gcc-c++
// 验证cpu是否支持kvm
[root@centos8 ~]# egrep -o 'vmx|svm' /proc/cpuinfo
vmx
vmx
vmx
vmx
vmx
vmx
vmx
vmx
// 结果中有vmx或svm字样，就说明cpu是支持的
kvm安装
[root@centos8 ~]# 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@centos8 ~]# cd /etc/sysconfig/network-scripts/
[root@centos8 network-scripts]# ls
ifcfg-ens33
[root@centos8 network-scripts]# cp ifcfg-ens33 ifcfg-br0
[root@centos8 network-scripts]# vi ifcfg-br0
[root@centos8 network-scripts]# cat ifcfg-br0
TYPE=Bridge
BOOTPROTO=static
NAME=br0
DEVICE=br0
ONBOOT=yes
IPADDR=192.168.91.137
PREFIX=24
GATEWAY=192.168.91.2
DNS1=114.114.114.114
[root@centos8 network-scripts]# vi ifcfg-ens33
[root@centos8 network-scripts]# cat ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
ONBOOT=yes
IPV6_PRIVACY=no
BRIDGE=br0
// 重启网卡
[root@centos8 network-scripts]# systemctl restart NetworkManager
[root@centos8 network-scripts]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:8a:0d:b0 brd ff:ff:ff:ff:ff:ff
inet 192.168.91.137/24 brd 192.168.91.255 scope global dynamic noprefixroute ens33
valid_lft 1718sec preferred_lft 1718sec
inet6 fe80::f9bd:6b78:9231:1fca/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: br0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether d6:b7:6d:60:18:cb brd ff:ff:ff:ff:ff:ff
inet 192.168.91.137/24 brd 192.168.91.255 scope global noprefixroute br0
valid_lft forever preferred_lft forever
启动kvm并验证安装结果
// 启动KVM
[root@centos8 network-scripts]# systemctl enable --now libvirtd
[root@centos8 network-scripts]# systemctl status libvirtd
● libvirtd.service - Virtualization daemon
Loaded: loaded (/usr/lib/systemd/system/libvirtd.service>
Active: active (running) since Wed 2021-10-20 22:49:02 C>
Docs: man:libvirtd(8)
https://libvirt.org
Main PID: 6659 (libvirtd)
Tasks: 19 (limit: 32768)
Memory: 47.3M
CGroup: /system.slice/libvirtd.service
├─1574 /usr/sbin/dnsmasq --conf-file=/var/lib/li>
├─1575 /usr/sbin/dnsmasq --conf-file=/var/lib/li>
└─6659 /usr/sbin/libvirtd --timeout 120
Oct 20 22:49:02 centos8 systemd[1]: Starting Virtualization>
Oct 20 22:49:02 centos8 systemd[1]: Started Virtualization >
Oct 20 22:49:02 centos8 dnsmasq[1574]: read /etc/hosts - 2 >
Oct 20 22:49:02 centos8 dnsmasq[1574]: read /var/lib/libvir>
Oct 20 22:49:02 centos8 dnsmasq-dhcp[1574]: read /var/lib/l>
// 验证安装结果
[root@centos8 network-scripts]# lsmod | grep kvm
kvm_intel 311296 0
kvm 839680 1 kvm_intel
irqbypass 16384 1 kvm
测试安装结果并查看网桥信息
[root@centos8 network-scripts]# virsh -c qemu:///system list
setlocale: No such file or directory
Id Name State
--------------------
[root@centos8 network-scripts]# virsh --version
setlocale: No such file or directory
6.0.0
[root@centos8 network-scripts]# virt-install --version
2.2.1
[root@centos8 network-scripts]# ln -s /usr/libexec/qemu-kvm /usr/bin/qemu-kvm
[root@centos8 network-scripts]# ll /usr/bin/qemu-kvm
lrwxrwxrwx 1 root root 21 Oct 20 22:52 /usr/bin/qemu-kvm -> /usr/libexec/qemu-kvm
[root@centos8 network-scripts]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.000c298a0db0 no ens33
virbr0 8000.525400211622 yes virbr0-nic
kvm web管理界面安装（centos7）
安装依赖包
[root@centos7 ~]# yum -y install epel-release
[root@centos7 ~]# yum -y install git python-pip libvirt-python libxml2-python python-websockify supervisor nginx python-devel python-*
从github下载webbvirtmgr代码
[root@centos7 ~]# cd /usr/local/src/
[root@centos7 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 | 51.00 KiB/s, done.
处理 delta 中: 100% (3606/3606), done.
安装webvirtmgr
[root@centos7 src]# cd webvirtmgr/
[root@centos7 webvirtmgr]# pip install -r requirements.txt
// 检查sqlite3是否安装
[root@centos7 webvirtmgr]# python
Python 2.7.5 (default, Nov 16 2020, 22:23:17)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlite3
>>> exit()
// 初始化账户信息
[root@centos7 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'): //指定超级管理员帐号用户名，默认留空为root
Email address: 2@1qq.com //设置管理员邮箱
Password:
Password (again): // 设置密码
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@centos7 webvirtmgr]# mkdir /var/www
[root@centos7 webvirtmgr]# cp -r /usr/local/src/webvirtmgr/ /var/www/
[root@centos7 webvirtmgr]# chown -R nginx.nginx /var/www/webvirtmgr/
生成密钥
[root@centos7 webvirtmgr]# 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:QYz85Lh7R0XOu+0AbDIV/ie8Bz81UvBNtLsZ0p4lVc4 root@centos7
The key's randomart image is:
+---[RSA 2048]----+
| . o. . . .+|
| o.o. .. o++|
| =. o+ +E|
| . o+ o+ o..|
| .S +.=+o=o|
| . +...*+oB|
| . . oo+= |
| . . . .o.. |
| . . .. |
+----[SHA256]-----+
[root@centos7 webvirtmgr]# ssh-copy-id 192.168.91.137
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
The authenticity of host '192.168.91.137 (192.168.91.137)' can't be established.
ECDSA key fingerprint is SHA256:CHl+F/ZU1pC0SQ7a5/IlsoVQoRXN/TMa3ikGYM1hsoA.
ECDSA key fingerprint is MD5:48:4a:3f:2f:ae:35:0d:6d:66:f8:f1:bf:c7:d8:f6:96.
Are you sure you want to continue connecting (yes/no)? 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@192.168.91.137's password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh '192.168.91.137'"
and check to make sure that only the key(s) you wanted were added.
配置端口转发
[root@centos7 webvirtmgr]# ssh 192.168.91.137 -L localhost:8000:localhost:8000 -L localhost:6080:localhost:60
Last login: Wed Oct 20 22:46:25 2021 from 192.168.91.1
[root@centos8 ~]# 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 [::]:111 [::]:*
LISTEN 0 128 [::]:22 [::]:*
配置nginx
[root@centos7 webvirtmgr]# vim /etc/nginx/nginx.conf
[root@centos7 webvirtmgr]# cat /etc/nginx/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 {
}
}
}
[root@centos7 webvirtmgr]# vim /etc/nginx/conf.d/webvirtmgr.conf
[root@centos7 webvirtmgr]# 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 $remote_addr;
proxy_connect_timeout 600;
proxy_read_timeout 600;
proxy_send_timeout 600;
client_max_body_size 1024M;
}
}
// 确保绑定的端口为8000
[root@centos7 webvirtmgr]# vim /var/www/webvirtmgr/conf/gunicorn.conf.py
bind = '0.0.0.0:8000'
// 重启nginx
[root@centos7 webvirtmgr]# systemctl restart nginx
[root@centos7 webvirtmgr]# ss -atnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 127.0.0.1:6080 *:*
LISTEN 0 128 127.0.0.1:8000 *:*
LISTEN 0 128 *:80 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 ::1:6080 :::*
LISTEN 0 128 ::1:8000 :::*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
设置supervisor
[root@centos7 webvirtmgr]# vim /etc/supervisord.conf
[program:webvirtmgr]
command=/usr/bin/python2 /var/www/webvirtmgr/manage.py run_gunicorn -c /var/www/webvirtmgr/conf/gunicorn.conf.py
directory=/var/www/webvirtmgr
autostart=true
autorestart=true
logfile=/var/log/supervisor/webvirtmgr.log
log_stderr=true
user=nginx
[program:webvirtmgr-console]
command=/usr/bin/python2 /var/www/webvirtmgr/console/webvirtmgr-console
directory=/var/www/webvirtmgr
autostart=true
autorestart=true
stdout_logfile=/var/log/supervisor/webvirtmgr-console.log
redirect_stderr=true
user=nginx
// 设置开机自启supervisor
[root@centos7 webvirtmgr]# systemctl enable --now supervisord
Created symlink from /etc/systemd/system/multi-user.target.wants/supervisord.service to /usr/lib/systemd/system/supervisord.service.
配置nginx用户
[root@centos7 ~]# su - nginx -s /bin/bash
-bash-4.2$ 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:mKX6w776z4izWhkGKbp9/0AD0+xS6cU7eVwunrjHFok nginx@centos7
The key's randomart image is:
+---[RSA 2048]----+
| |
| . o o |
|. o o = + . |
|.. . * * + o |
|. + O S.+.. |
| o . * .E=oo |
|. . =.. ..o. |
| o.+o+ .+ |
| ..+*B==o |
+----[SHA256]-----+
-bash-4.2$
-bash-4.2$ touch ~/.ssh/config && echo -e "StrictHostKeyChecking=no\nUserKnownHostsFile=/dev/null" >> ~/.ssh/config
-bash-4.2$ chmod 0600 ~/.ssh/config
-bash-4.2$ ssh-copy-id root@192.168.91.137
/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 '192.168.91.137' (ECDSA) to the list of known hosts.
root@192.168.91.137's password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh 'root@192.168.91.137'"
and check to make sure that only the key(s) you wanted were added.
-bash-4.2$ exit
登出
[root@centos7 ~]# 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@centos7 ~]# chown -R root.root /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla
[root@centos7 ~]# systemctl restart nginx
[root@centos8 ~]# systemctl restart libvirtd
四、kvm web界面管理
通过ip地址在浏览器上访问kvm
创建SSH连接
kvm存储管理
通过远程连接软件上传ISO镜像文件至存储目录/var/lib/libvirt/images/
[root@centos8 ~]# cd /var/lib/libvirt/images/
[root@centos8 images]# ls
[root@centos8 images]# ls
CentOS-7-x86_64-DVD-1804-7.5.iso
在 web 界面查看ISO镜像是否存在
添加网络
启动
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