Linux下KVM虚拟机基本管理及常用命令

迈不过友情╰ 2022-04-16 03:58 242阅读 0赞

**说明：可能有重复**

**一、KVM的基本管理**

**1、查看KVM虚拟机配置文件**

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#Kvm虚拟机默认配置文件位置
    [root@kvm qemu]# pwd
    /etc/libvirt/qemu
    [root@kvm qemu]# ll
    total 12
    -rw------- 1 root root 3863 Nov  6 17:26 CentOS6.5.xml
    -rw------- 1 root root 3771 Nov  7 00:57 CentOS6u7.xml
    -rw------- 1 root root 3628 Nov  7 02:04 centos.xml
    drwx------ 3 root root   40 Nov  7 00:46 networks

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**2、启动与关闭**

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#显示正在运行的虚拟机
    [root@kvm ~]# virsh list
     Id    Name                           State
    ----------------------------------------------------
    
    #显示所有虚拟机
    [root@kvm ~]# virsh list --all
     Id    Name                           State
    ----------------------------------------------------
     -     centos                         shut off
     -     CentOS6.5                      shut off
     -     CentOS6u7                      shut off
    
    #启动名字为CentOS6.5的虚拟机
    [root@kvm ~]# virsh start CentOS6.5
    
    #关闭名字为CentOS6.5的虚拟机
    [root@kvm ~]# virsh shutdown CentOS6.5
    
    #强制关闭名字为Centos6.5的虚拟机 
    [root@kvm ~]# virsh destroy CentOS6.5
    
    #移除名字为CentOS6.5的虚拟机 
    [root@kvm ~]# virsh undefine CentOS6.5
    
    #设置CentOS6.5虚拟机开机启动 
    [root@kvm ~]# virsh autostart CentOS6.5
    
    #默认情况下virsh工具不能对linux虚拟机进行关机操作
    #linux操作系统需要开启与启动acpid服务。在安装KVM linux虚拟机必须配置此服务。
    # yum -y install acpid
    # /etc/init.d/acpid start

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**3、通过配置文件启动虚拟机**

[root@kvm ~]# virsh create /etc/libvirt/qemu/CentOS6.5.xml

**4、其它（挂起，恢复）virsh命令**

#挂起服务器
    [root@kvm qemu]# virsh suspend CentOS6.5
    
    #恢复服务器
    [root@kvm qemu]# virsh resume CentOS6.5

**5、重命名虚拟机**

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#停止虚拟机
    [root@kvm qemu]# virsh shutdown CentOS6u5
    
    #导出虚拟机的配置文件
    [root@kvm qemu]# pwd
    /etc/libvirt/qemu
    [root@kvm qemu-img]# virsh dumpxml CentOS6u5 > test-CentOS6u5.xml
    
    #更改配置文件
    [root@kvm qemu]# sed -i 's/CentOS6u5/test-CentOS6u5/g' test-CentOS6u5.xml
    #注 可以不用更改镜像名
    
    #移除原有的虚拟机
    [root@kvm qemu]# virsh undefine CentOS6u5
    
    #加载新建的虚拟机
    [root@kvm qemu]# virsh define test-CentOS6u5.xml
    
    #启动虚拟机
    [root@kvm qemu]# virsh start test-CentOS6u5

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**6、虚拟机创建快照**

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#转换磁盘镜像文件格式为qcow2
    [root@kvm ~]# virsh shutdown test-CentOS6u5
    [root@kvm qemu-img]# qemu-img convert -f raw CentOS6u5.raw -O qcow2 CentOS6u5.raw.qcow2
    #快照一定需要qcow2格式才行 
    #我这边从新建立一个虚拟机以qcow2
    
    #创建快照
    [root@kvm qemu-img]# virsh snapshot-create CentOS6u5
    
    #查看快照
    [root@kvm qemu-img]# virsh snapshot-list CentOS6u5
     Name                 Creation Time             State
    ------------------------------------------------------------
     1479043349           2016-11-13 08:22:29 -0500 shutoff
    
    #恢复快照
    [root@kvm qemu-img]# virsh snapshot-revert CentOS6u5  1479043349
    
    #删除快照
    [root@kvm qemu-img]# virsh snapshot-delete CentOS6u5 1479043349

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**二、常用命令**

列出所有的虚拟机

virsh list --all

显示虚拟机信息

virsh dominfo kvm-1

显示虚拟机内存和cpu的使用情况

yum install virt-top -y
    virt-top

显示虚拟机分区信息

virt-df kvm-1

关闭虚拟机（shutodwn）

virsh shutdown kvm-1

启动虚拟机

virsh start kvm-1

设置虚拟机（kvm-1）跟随系统自启

virsh autostart kvm-1

关闭虚拟及自启

virsh autostart --disable kvm-1

删除虚拟机

virsh undefine kvm-1

通过控制窗口登录虚拟机

virsh console kvm-1

其它

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virsh shutdown centos        关闭centos虚拟机
    virsh destroy centos            强制关闭centos虚拟机
    virsh suspend centos        暂停centos虚拟机
    vrish resume centos            恢复centos虚拟机
    virsh reboot centos            重启centos虚拟机
    virsh edit centos                编辑centos虚拟机
    virsh vncdisplay  centos    vnc显示

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**给虚拟机添加硬盘**

添加硬盘（lvm卷）或者USB到虚拟机上

virsh attach-disk kvm-1 /dev/sdb vbd --driver qemu --mode shareable

使用完成之后可以卸载usb

virsh detach-disk kvm vdb

添加lvm卷，并挂载

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[root@sh-kvm-1 ~]# lvcreate -n kvm-1-data -L 50G vg_shkvm1
    [root@sh-kvm-1 ~]# virsh attach-disk kvm-1 /dev/vg_shkvm1/kvm-1-data vdb --driver qemu --mode shareable
    Disk attached successfully
    # 登录到kvm-1上查看lvm是否已经被挂载
    [root@sh-kvm-1 ~]# virsh console kvm-1 # 输入kvm-1的用户和密码
    [root@sh-kvm-1-1 ~]# fdisk -l # 查看硬盘挂载情况
    
    Disk /dev/vda: 21.5 GB, 21474836480 bytes
    16 heads, 63 sectors/track, 41610 cylinders
    Units = cylinders of 1008 * 512 = 516096 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00058197
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/vda1   *           3        1018      512000   83  Linux
    Partition 1 does not end on cylinder boundary.
    /dev/vda2            1018       41611    20458496   8e  Linux LVM
    Partition 2 does not end on cylinder boundary.
    
    Disk /dev/mapper/VolGroup-lv_root: 18.8 GB, 18798870528 bytes
    255 heads, 63 sectors/track, 2285 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00000000
    
    
    Disk /dev/mapper/VolGroup-lv_swap: 2147 MB, 2147483648 bytes
    255 heads, 63 sectors/track, 261 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00000000
    
    
    Disk /dev/vdb: 53.7 GB, 53687091200 bytes  # 新添加的硬盘
    16 heads, 63 sectors/track, 104025 cylinders
    Units = cylinders of 1008 * 512 = 516096 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00000000

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格式化新添加的vdb，并添加到lvm组中

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# 对新添加的硬盘分区
    [root@sh-kvm-1-1 ~]# fdisk /dev/vdb
    Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
    Building a new DOS disklabel with disk identifier 0xf04b6807.
    Changes will remain in memory only, until you decide to write them.
    After that, of course, the previous content won't be recoverable.
    
    Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
    
    WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
             switch off the mode (command 'c') and change display units to
             sectors (command 'u').
    
    Command (m for help): m  # 查看帮助
    Command action
       a   toggle a bootable flag
       b   edit bsd disklabel
       c   toggle the dos compatibility flag
       d   delete a partition
       l   list known partition types
       m   print this menu
       n   add a new partition
       o   create a new empty DOS partition table
       p   print the partition table
       q   quit without saving changes
       s   create a new empty Sun disklabel
       t   change a partition's system id
       u   change display/entry units
       v   verify the partition table
       w   write table to disk and exit
       x   extra functionality (experts only)
    Command (m for help): n  #添加一个分区
    Command action
       e   extended
       p   primary partition (1-4)
    p  #选择添加一个扩展分区
    Partition number (1-4):
    Value out of range.
    Partition number (1-4): 1
    First cylinder (1-104025, default 1):
    Using default value 1
    Last cylinder, +cylinders or +size{K,M,G} (1-104025, default 104025):
    Using default value 104025
    
    Command (m for help): t  #改变分区的格式
    Selected partition 1
    Hex code (type L to list codes): 8e  #改成lvm
    Changed system type of partition 1 to 8e (Linux LVM)
    
    Command (m for help): w  # 保存更改
    root@sh-kvm-1-1 ~]# mkfs.ext4 /dev/vdb1  # 格式化分区
    mke2fs 1.41.12 (17-May-2010)
    Filesystem label=
    OS type: Linux
    Block size=4096 (log=2)
    Fragment size=4096 (log=2)
    Stride=0 blocks, Stripe width=0 blocks
    3276800 inodes, 13107142 blocks
    655357 blocks (5.00%) reserved for the super user
    First data block=0
    Maximum filesystem blocks=4294967296
    400 block groups
    32768 blocks per group, 32768 fragments per group
    8192 inodes per group
    Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424
    
    Writing inode tables: done
    Creating journal (32768 blocks): done
    Writing superblocks and filesystem accounting information: done
    
    This filesystem will be automatically checked every 28 mounts or
    180 days, whichever comes first.  Use tune2fs -c or -i to override.
    [root@sh-kvm-1-1 ~]# pvc reate /dev/vdb1   # 创建pv
    vdb   vdb1
    [root@sh-kvm-1-1 ~]# vgextend VolGroup /dev/vdb  # 扩展lvm vg
    vdb   vdb1
    [root@sh-kvm-1-1 ~]# vgs
      VG       #PV #LV #SN Attr   VSize  VFree
      VolGroup   2   2   0 wz--n- 69.50g 50.00g
    # 从上面能看出，新添加的 已经加到lvm组中

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**改变虚拟机的参数**

通过命令行更改创建之后虚拟机的内存，cpu等信息

更改内存

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# 1. 查看虚拟机当前内存
    [root@sh-kvm-1 ~]# virsh dominfo kvm-1 | grep memory
    Max memory:     4194304 KiB
    Used memory:    4194304 KiB
    
    # 2、动态设置内存为512MB，内存减少
    virsh setmem kvm-1 524288
    # 注意单位必须是KB
    
    # 3、查看内存变化
    # virsh dominfo kvm-1 | grep memory
    Max memory: 14194304 KiB
    Used memory: 524288 kiB
    
    # 4、内存增加
    virsh shutdown kvm-1
    virsh edit kvm-1  # 直接更改memory
    virsh create /etc/libvirt/demu/kvm-1/xml
    # 之后操作1,2,3步骤增加内存

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更改CPU

需要修改配置文件，因此需要停止虚拟机

virsh shutdown kvm-1
    virsh edit kvm-1
    #  <vcpu>2</vcpu>  # 4 > 2
    virsh create /etc/libvirt/demu/kvm-1/xml

硬盘扩容

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1. Create a 10-GB non-sparse file:
    # dd if=/dev/zero of=/vm-images/vm1-add.img bs=1M count=10240
    2. Shutdown the VM:
     # virsh shutdown vm1
    3. Add an extra entry for ‘disk’ in the VM's XML file in /etc/libvirt/qemu. You can look copy & paste the entry for your mail storage device and just change the target and address tags. For example:
     # virsh edit vm1
     <disk type='file' device='disk'>
     <driver name='qemu' type='raw' cache='none' io='threads'/>
     <source file='/vm-images/vm1.img'/>
     <target dev='vda' bus='virtio'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
     </disk>
     Add:
     <disk type='file' device='disk'>
     <driver name='qemu' type='raw' cache='none' io='threads'/>
     <source file='/vm-images/vm1-add.img'/>
     <target dev='vdb' bus='virtio'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
     </disk>
     # 这里建议使用上面的添加硬盘的方式添加

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**删除虚拟机**

第一步，停掉虚拟机

virsh shutdown kvm-1

第二步

virsh destroy kvm-1

第三步

virsh undefine kvm-1

第四步

rm /dev/vg_shkvm1/kvm-1  # 不建议删除硬

[Image 1]: