虚拟化：
全虚拟化 裸金属(没有操作系统，纯硬件)上部署，性能强，不能嵌套
半虚拟化 OS(系统)部署 嵌套

虚拟化实现方式：

• kvm *
• esxi *
• xen
• citrix (银行)
• hyper-v
• vmware workstation
• virualbox

1. 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）。

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

讯享网
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

2. kvm介绍

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

3. kvm部署

环境说明：

3.1 kvm安装

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 ~]# hostnamectl set-hostname kvm [root@localhost ~]# bash [root@kvm ~]# systemctl stop firewalld [root@kvm ~]# systemctl disable firewalld Removed /etc/systemd/system/multi-user.target.wants/firewalld.service. Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service. [root@kvm ~]# setenforce 0 [root@kvm ~]# sed -ri 's/^(SELINUX=).*/\1disabled/g' /etc/selinux/config [root@kvm ~]# reboot //安装需要的包 [root@kvm ~]# dnf -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@kvm ~]# egrep -o 'vmx|svm' /proc/cpuinfo vmx //kvm安装 [root@kvm ~]# dnf -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@kvm ~]# cd /etc/sysconfig/network-scripts/ [root@kvm network-scripts]# cp ifcfg-ens33 ifcfg-br0 [root@kvm network-scripts]# ls ifcfg-br0 ifcfg-ens33 [root@kvm network-scripts]# cat ifcfg-ens33  TYPE=Ethernet BOOTPROTO=static NAME=ens33 DEVICE=ens33 ONBOOT=yes BRIDGE=br0 [root@kvm network-scripts]# vim ifcfg-br0  [root@kvm network-scripts]# cat ifcfg-br0  TYPE=Bridge BOOTPROTO=static NAME=br0 DEVICE=br0 ONBOOT=yes IPADDR=192.168.235.160 NETMASK=255.255.255.0 GATEWAY=192.168.235.1 DNS1=114.114.114.114 DNS2=8.8.8.8 [root@kvm ~]# systemctl restart NetworkManager [root@kvm ~]# ifdown ens33;ifup ens33 错误："/etc/sysconfig/network-scripts/ifcfg-ens33" 不是活动的连接。 错误：未提供活动连接。 连接已成功激活（D-Bus 活动路径：/org/freedesktop/NetworkManager/ActiveConnection/4） [root@kvm ~]# 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 master br0 state UP group default qlen 1000 link/ether 00:0c:29:b8:d0:10 brd ff:ff:ff:ff:ff:ff 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether 52:54:00:2c:34:37 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 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 state DOWN group default qlen 1000 link/ether 52:54:00:2c:34:37 brd ff:ff:ff:ff:ff:ff 5: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 00:0c:29:b8:d0:10 brd ff:ff:ff:ff:ff:ff inet 192.168.235.160/24 brd 192.168.235.255 scope global noprefixroute br0 valid_lft forever preferred_lft forever inet6 fe80::20c:29ff:feb8:d010/64 scope link valid_lft forever preferred_lft forever //启动服务 [root@kvm ~]# systemctl start libvirtd [root@kvm ~]# systemctl enable libvirtd //验证安装结果 [root@kvm ~]# lsmod|grep kvm kvm_intel  0 kvm  1 kvm_intel irqbypass 16384 1 kvm //测试并验证安装结果 [root@kvm ~]# virsh -c qemu:///system list Id 名称 状态 ------------------- [root@kvm ~]# ln -s /usr/libexec/qemu-kvm /usr/bin/qemu-kvm [root@kvm ~]# ll /usr/bin/qemu-kvm lrwxrwxrwx 1 root root 21 10月 20 19:28 /usr/bin/qemu-kvm -> /usr/libexec/qemu-kvm [root@kvm ~]# which qemu-kvm /usr/bin/qemu-kvm //查看网桥信息 [root@kvm ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.000c29b8d010 no ens33 virbr0 8000.c3437 yes virbr0-nic 

3.2 kvm web管理界面安装

讯享网 [root@webvirtmgr ~]# 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@webvirtmgr ~]# cd /usr/local/src/ [root@webvirtmgr 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 | 789.00 KiB/s, done. 处理 delta 中: 100% (3606/3606), done. [root@webvirtmgr src]# ls webvirtmgr [root@webvirtmgr src]# cd webvirtmgr/ [root@webvirtmgr webvirtmgr]# ls conf dev-requirements.txt interfaces networks serverlog templates console hostdetail locale README.rst servers Vagrantfile create images manage.py requirements.txt setup.py vrtManager deploy instance MANIFEST.in secrets storages webvirtmgr [root@webvirtmgr webvirtmgr]#  //安装webvirtmgr [root@webvirtmgr ~]# cd /usr/local/src/webvirtmgr/ [root@webvirtmgr webvirtmgr]# pip install -r requirements.txt Collecting django==1.5.5 (from -r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/38/49/93511c5d3367b6b21fc2995a0eafc15e4cd6eb57be879ae13ad4/Django-1.5.5.tar.gz (8.1MB) 100% |████████████████████████████████| 8.1MB 96kB/s //检查sqlite3是否安装 [root@webvirtmgr webvirtmgr]# python Python 2.7.5 (default, Nov 16 2020, 22:23:17) [GCC 4.8.5  (Red Hat 4.8.5-44)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import sqlite3 >>> exit() //初始化帐号信息 [root@webvirtmgr 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:  //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@webvirtmgr webvirtmgr]# mkdir /var/www [root@webvirtmgr webvirtmgr]# cp -r /usr/local/src/webvirtmgr /var/www/ [root@webvirtmgr webvirtmgr]# chown -R nginx.nginx /var/www/webvirtmgr/ [root@webvirtmgr webvirtmgr]#  //生成密钥 [root@webvirtmgr 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:amfQhlsLmLCD0u3FZzsZF++sLCOhbrAImAJiqsE root@webvirtmgr The key's randomart image is: +---[RSA 2048]----+ |Xo | |@ | |=E. | |o+ + + o | |+.+ + O S | |o. + = B . | |.o* o + + | |o===.. o | |=+*B. | +----[SHA256]-----+ [root@webvirtmgr webvirtmgr]# ssh-copy-id 192.168.235.160 /usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub" The authenticity of host '192.168.235.160 (192.168.235.160)' can't be established. ECDSA key fingerprint is SHA256:ghl+21XZYuW114MkJUxv0903+4ODkTu9/LSiIwwkBm8. ECDSA key fingerprint is MD5:7d:4b:d0:3f:39:d6:61:5f:20:7a:07:8e:9e:00:65:0b. 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@192.168.235.160's password: Number of key(s) added: 1 Now try logging into the machine, with: "ssh '192.168.235.160'" and check to make sure that only the key(s) you wanted were added. [root@webvirtmgr ~]# ssh root@192.168.235.160 -L localhost:8000:localhost:8000 -L localhost:6080:localhost:60 Last login: Wed Oct 20 21:09:17 2021 from 192.168.235.1 [root@kvm ~]# 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@webvirtmgr ~]# cd /etc/nginx/ [root@webvirtmgr nginx]# ls conf.d fastcgi_params.default nginx.conf uwsgi_params.default default.d koi-utf nginx.conf.default win-utf fastcgi.conf koi-win scgi_params fastcgi.conf.default mime.types scgi_params.default fastcgi_params mime.types.default uwsgi_params [root@webvirtmgr nginx]# cp nginx.conf{,bak} [root@webvirtmgr nginx]# > nginx.conf [root@webvirtmgr nginx]# vi nginx.conf [root@webvirtmgr 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 { } } } [root@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bind绑定的是本机的8000端口 [root@webvirtmgr ~]# vim /var/www/webvirtmgr/conf/gunicorn.conf.py 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 backlog = 2048 //重启nginx [root@webvirtmgr ~]# systemctl restart nginx [root@webvirtmgr ~]# ss -antl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:80 *:* LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* //设置supervisor [root@webvirtmgr ~]# vim /etc/supervisord.conf .....此处省略上面的内容，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@webvirtmgr ~]# systemctl start supervisord [root@webvirtmgr ~]# systemctl enable supervisord Created symlink from /etc/systemd/system/multi-user.target.wants/supervisord.service to /usr/lib/systemd/system/supervisord.service. [root@webvirtmgr ~]# systemctl status supervisord ● supervisord.service - Process Monitoring and Control Daemon Loaded: loaded (/usr/lib/systemd/system/supervisord.service; enabled; vendor preset: disabled) Active: active (running) since 三 2021-10-20 21:35:40 CST; 12s ago Main PID: 62125 (supervisord) CGroup: /system.slice/supervisord.service ├─62125 /usr/bin/python /usr/bin/supervisord -c /etc/supervisord.conf ├─62159 /usr/bin/python2 /var/www/webvirtmgr/console/webvirtmgr-console ├─62160 /usr/bin/python2 /var/www/webvirtmgr/manage.py run_gunicorn -c /var/... ├─62178 /usr/bin/python2 /var/www/webvirtmgr/manage.py run_gunicorn -c /var/... ├─62179 /usr/bin/python2 /var/www/webvirtmgr/manage.py run_gunicorn -c /var/... └─62180 /usr/bin/python2 /var/www/webvirtmgr/manage.py run_gunicorn -c /var/... 10月 20 21:35:40 webvirtmgr systemd[1]: Starting Process Monitoring and Control Daemon... 10月 20 21:35:40 webvirtmgr systemd[1]: Started Process Monitoring and Control Daemon. Hint: Some lines were ellipsized, use -l to show in full. [root@webvirtmgr ~]# ss -antl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:8000 *:* LISTEN 0 100 *:6080 *:* LISTEN 0 128 *:80 *:* LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* //配置nginx用户 [root@webvirtmgr ~]# 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:O95E0FNNI0jAW2rFdfg6DgkdESyG76oOx5Ya+T2UKaw nginx@webvirtmgr The key's randomart image is: +---[RSA 2048]----+ | o.=+=+++ | | . +.B..o.. | | o.Bo. . | | *... . | | . =S... . | | oo.+ .oo o | | +.=o .o .o . | | EB .o. + . | | ..+.... . | +----[SHA256]-----+ -bash-4.2$ touch ~/.ssh/config && echo -e "StrictHostKeyChecking=no\nUserKnownHostsFile=/dev/null" StrictHostKeyChecking=no UserKnownHostsFile=/dev/null -bash-4.2$ chmod 0600 ~/.ssh/config -bash-4.2$ ssh-copy-id root@192.168.235.160 /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 '192.168.235.160' (ECDSA) to the list of known hosts. root@192.168.235.160's password: Number of key(s) added: 1 Now try logging into the machine, with: "ssh 'root@192.168.235.160'" and check to make sure that only the key(s) you wanted were added. -bash-4.2$ exit 登出 [root@webvirtmgr ~]# vim /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla [root@webvirtmgr ~]# 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@webvirtmgr ~]# chown -R root.root /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla [root@kvm ~]# systemctl restart libvirtd  [root@webvirtmgr ~]# systemctl restart nginx 

3.3.2 kvm存储管理

创建存储：

 [root@kvm ~]# cd /var/lib/libvirt/images/ [root@kvm images]# ls [root@kvm images]# ls CentOS-7-x86_64-DVD-1804-7.5.iso 

3.3.3 kvm网络管理

3.3.4 实例管理

4.故障案例

web界面配置完成后可能会出现以下错误界面

第一次通过web访问kvm时可能会一直访问不了，一直转圈，而命令行界面一直报错(too many open files)
此时需要对nginx进行配置

讯享网[root@localhost ~]# vim /etc/nginx/nginx.conf ....此处省略N行 user nginx; worker_processes auto; error_log /var/log/nginx/error.log; pid /run/nginx.pid; worker_rlimit_nofile ; //添加此行配置 # Load dynamic modules. See /usr/share/nginx/README.dynamic. ....此处省略N行 [root@localhost ~]# systemctl restart nginx 然后对系统参数进行设置 [root@localhost ~]# vim /etc/security/limits.conf ....此处省略N行 # End of file * soft nofile  * hard nofile