KVM 虚拟化-centos8
目录
一、安装软件
二、开启服务（保证qemu正常运行）
三、使用命令调出图形化工具
四、命令行管理
1.查看默认网桥
2.删除默认网桥
3.通过nmcli创建虚拟bridge
4.使用cloud镜像拉取虚拟机
1）下载
2）创建目录存放qcow2文件
3)自定义qcow2文件
4）利用修改后的qcow2文件拉取虚拟机
5）查看虚拟机
6)进去虚拟机控制台
7）配置虚拟机的ip地址
5.扩展虚拟机的根分区
1）干掉虚拟机
2）使用virt-filesystems命令查看qcow2文件的分区情况
3）重新创建更大的qcow2文件
4）查看重新创建qcow2文件
5）让重新生成的qcow2文件替换原先的qcow2文件
6）再次查看qcow2文件分区
7）再次拉取虚拟机
8）ssh进入虚拟机进行测试
五、为虚拟机配置桥接网络（选做）
一、安装软件
[root@KVM ~]# yum -y install virt*
二、开启服务（保证qemu正常运行）
[root@KVM ~]# systemctl enable libvirtd --now
三、使用命令调出图形化工具
[root@KVM ~]# virt-manager 本文不在详细说明图形化管理，侧重于命令行。利用现有qocw2文件拉取虚拟机
四、命令行管理
1.查看默认网桥
[root@KVM ~]# virsh net-list --all
Name State Autostart Persistent
--------------------------------------------
default active yes yes
2.删除默认网桥
[root@KVM ~]# virsh net-destroy default
Network default destroyed
[root@KVM ~]# virsh net-undefine default
Network default has been undefined
[root@KVM ~]# virsh net-list --all
Name State Autostart Persistent
----------------------------------------
3.通过nmcli创建虚拟bridge
[root@KVM ~]# nmcli con add con-name vm-1 ifname vm-1 type bridge ipv4.address 100.100.100.100/24 ipv4.method manual
Connection 'vm-1' (2c4531f3-7658-45a5-b320-acfab8898100) successfully added.
4.使用cloud镜像拉取虚拟机
1）下载
网址: CentOS Cloud images
[root@KVM ~]wget https://cloud.centos.org/centos/8-stream/x86_64/images/CentOS-StreamGenericCloud-8-20220125.1.x86_64.qcow22）创建目录存放qcow2文件
[root@KVM ~]# mkdir /usr/images
[root@KVM ~]# mv CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2 /usr/images/#一般不会将qcow2文件放到/tmp下，因为默认情况下/tmp目录会周期性的自我清理，容易干掉qcow2文件， 所以你可以将qcow2文件放到别的目录，但是这个目录必须要对qemu有rwx权限才可以拉起虚拟机。
3)自定义qcow2文件
当我们使用qcow2文件拉取虚拟机时，不知道root用户密码，无法正常进入虚拟机，在进行批量部署时，我们不可能每次都进入系统破解root密码，所以通过修改现有的qocw2文件，设置密码，便于我们正常进入系统。
[root@KVM ~]# virt-customize -a /usr/images/CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2 --root-password password:1 --selinux-relabel
[ 0.0] Examining the guest ...
[ 33.4] Setting a random seed
[ 33.4] Setting the machine ID in /etc/machine-id
[ 33.4] Setting passwords
[ 35.5] SELinux relabelling
[ 50.3] Finishing off4）利用修改后的qcow2文件拉取虚拟机
[root@KVM ~]# virt-install --name centos-stream8-1 --memory 1024 --vcpus 1 --import --os-variant centos-stream8 --disk /usr/images/CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2,bus=virtio --network bridge=vm-1,model=virtio --noautoconsole
WARNING Requested memory 1024 MiB is less than the recommended 1536 MiB for OS centos-stream8
Starting install...
Domain creation completed.
5）查看虚拟机
[root@KVM ~]# virsh list --all
Id Name State
----------------------------------
1 centos-stream8-1 running6)进去虚拟机控制台
[root@KVM ~]# virsh console centos-stream8-1
Connected to domain 'centos-stream8-1'
Escape character is ^] (Ctrl + ])
CentOS Stream 8
Kernel 4.18.0-358.el8.x86_64 on an x86_64
Activate the web console with: systemctl enable --now cockpit.socket
localhost login: root
Password:
[root@localhost ~]#
7）配置虚拟机的ip地址
nmcli con add con-name node1 ifname eth0 type ethernet ipv4.address 100.100.100.2/24 ipv4.method man
nmcli con up node1此时通过ssh即可连接虚拟机
[root@KVM ~]# ssh 100.100.100.2
The authenticity of host '100.100.100.2 (100.100.100.2)' can't be established.
ECDSA key fingerprint is SHA256:xzzxEjrvLCi131Ou5M0N059a0SPXoJpTUX4Ai7aGgi8.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '100.100.100.2' (ECDSA) to the list of known hosts.
[email protected]'s password:
Activate the web console with: systemctl enable --now cockpit.socket
Last login: Tue May 10 14:43:42 2022
5.扩展虚拟机的根分区
1）干掉虚拟机
[root@KVM ~]# virsh destroy centos-stream8-1
Domain 'centos-stream8-1' destroyed
[root@KVM ~]# virsh undefine centos-stream8-1
Domain 'centos-stream8-1' has been undefined
2）使用virt-filesystems命令查看qcow2文件的分区情况
[root@KVM ~]# virt-filesystems --long -h --all -a /usr/images/CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2
Name Type VFS Label MBR Size Parent
/dev/sda1 filesystem xfs - - 7.8G -
/dev/sda1 partition - - 83 7.8G /dev/sda
/dev/sda device - - - 10G -
3）重新创建更大的qcow2文件
[root@KVM ~]# qemu-img create -f qcow2 /usr/images/os.qcow2 200G
Formatting '/usr/images/os.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=214748364800 lazy_refcounts=off refcount_bits=164）查看重新创建qcow2文件
[root@KVM ~]# qemu-img info /usr/images/os.qcow2
image: /usr/images/os.qcow2
file format: qcow2
virtual size: 200 GiB (214748364800 bytes)
disk size: 196 KiB
cluster_size: 65536
Format specific information:
compat: 1.1
compression type: zlib
lazy refcounts: false
refcount bits: 16
corrupt: false
extended l2: false5）让重新生成的qcow2文件替换原先的qcow2文件
此步骤可以理解为夺舍，/CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2 文件的灵魂去夺舍os.qcow2文件的灵魂。夺舍后新的os.qocw2文件使用新的肉体，老的灵魂。
[root@KVM ~]# virt-resize --expand /dev/sda1 /usr/images/CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2 /usr/images/os.qcow2
[ 0.0] Examining /usr/images/CentOS-Stream-GenericCloud-8-20220125.1.x86_64.qcow2
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
**********
Summary of changes:
/dev/sda1: This partition will be resized from 7.8G to 200.0G. The
filesystem xfs on /dev/sda1 will be expanded using the ‘xfs_growfs’
method.
**********
[ 18.8] Setting up initial partition table on /usr/images/os.qcow2
[ 19.5] Copying /dev/sda1
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
[ 68.3] Expanding /dev/sda1 using the ‘xfs_growfs’ method
Resize operation completed with no errors. Before deleting the old disk,
carefully check that the resized disk boots and works correctly.
6）再次查看qcow2文件分区
[root@KVM ~]# virt-filesystems -lh --all -a /usr/images/os.qcow2
Name Type VFS Label MBR Size Parent
/dev/sda1 filesystem xfs - - 200G -
/dev/sda1 partition - - 83 200G /dev/sda
/dev/sda device - - - 200G -7）再次拉取虚拟机
[root@KVM ~]# virt-install --name centos-stream8-1 --memory 1024 --vcpus 1 --import --os-variant centos-stream8 --disk /usr/images/os.qcow2,bus=virtio --network bridge=vm-1,model=virtio --noautoconsole
WARNING Requested memory 1024 MiB is less than the recommended 1536 MiB for OS centos-stream8
Starting install...
Domain creation completed.8）ssh进入虚拟机进行测试
[root@KVM ~]# ssh 100.100.100.2
[email protected]'s password:
Activate the web console with: systemctl enable --now cockpit.socket
Last failed login: Tue May 10 15:11:06 UTC 2022 from 100.100.100.100 on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Tue May 10 15:10:40 2022 from 100.100.100.100
[root@localhost ~]# df -Th
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 368M 0 368M 0% /dev
tmpfs tmpfs 403M 0 403M 0% /dev/shm
tmpfs tmpfs 403M 11M 392M 3% /run
tmpfs tmpfs 403M 0 403M 0% /sys/fs/cgroup
/dev/vda1 xfs 200G 2.8G 198G 2% /
tmpfs tmpfs 81M 0 81M 0% /run/user/0可以发现虚拟机的根分区已经变为我们想要的大小了
五、为虚拟机配置桥接网络（选做）
当我们想要让虚拟机与internet访问，最简单的方法就是给虚拟机配置一个桥接网络
本文通过 network manager 来实现
[root@KVM ~]# nmcli connection modify manager slave-type bridge master vm-1
[root@KVM ~]# nmcli connection up manager
[root@KVM ~]# bridge link
2: ens33: mtu 1500 master vm-1 state forwarding priority 32 cost 100
11: vnet1: mtu 1500 master vm-1 state forwarding priority 32 cost 100 此时我们只需要给vm-1配一个网络，并且给虚拟机配置一个与vm-1同一网段的ip，即可实现通信。