KVM : Management tools for VM

	Install useful tools for virtual machine management.
[1]	Install required packages.

root@dlp:~#  apt -y install libguestfs-tools

[2]	Get official OS image and Create a Virtual Machine. ( If you'd like to create VM from OS installation, refer to here of [1] )

# display available OS template root@dlp:~#  virt-builder -l ..... ..... debian-6 x86_64 Debian 6 (Squeeze) debian-7 sparc64 Debian 7 (Wheezy) (sparc64) debian-7 x86_64 Debian 7 (wheezy) debian-8 x86_64 Debian 8 (jessie) debian-9 x86_64 Debian 9 (stretch) debian-10 x86_64 Debian 10 (buster) debian-11 x86_64 Debian 11 (bullseye) debian-12 x86_64 Debian 12 (bookworm) ..... ..... # create an image of Debian 12 root@dlp:~#  virt-builder debian-12 --format qcow2 --size 10G -o /var/kvm/images/debian-12.qcow2 --root-password password:myrootpassword [ 7.4] Downloading: http://builder.libguestfs.org/debian-12.xz [ 82.7] Planning how to build this image [ 82.7] Uncompressing [ 85.2] Resizing (using virt-resize) to expand the disk to 10.0G [ 100.4] Opening the new disk [ 107.9] Setting a random seed [ 107.9] Setting passwords [ 108.5] SELinux relabelling [ 108.6] Finishing off Output file: /var/kvm/images/debian-12.qcow2 Output size: 10.0G Output format: qcow2 Total usable space: 9.8G Free space: 8.6G (87%) # to configure VM with the image above, run virt-install root@dlp:~# virt-install \ --name debian-12 \ --ram 4096 \ --disk path=/var/kvm/images/debian-12.qcow2 \ --vcpus 2 \ --os-variant debian12 \ --network bridge=br0 \ --graphics none \ --noautoconsole \ --boot hd \ --noreboot \ --import Starting install... Creating domain... | 00:00:00 Domain creation completed. You can restart your domain by running: virsh --connect qemu:///system start debian-12

[3]	[ls] a directory in a virtual machine.

root@dlp:~#  virt-ls -l -d debian13 /root total 32 drwx------ 4 0 0 4096 Aug 21 00:07 . drwxr-xr-x 19 0 0 4096 Aug 20 23:53 .. -rw------- 1 0 0 58 Aug 21 01:08 .bash_history -rw-r--r-- 1 0 0 607 May 12 19:25 .bashrc drwx------ 2 0 0 4096 Aug 20 23:56 .cache -rw------- 1 0 0 20 Aug 21 00:07 .lesshst -rw-r--r-- 1 0 0 132 May 12 19:25 .profile drwx------ 2 0 0 4096 Aug 20 23:49 .ssh

[4]	[cat] a file in a virtual machine.

root@dlp:~#  virt-cat -d debian13 /etc/passwd root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin bin:x:2:2:bin:/bin:/usr/sbin/nologin sys:x:3:3:sys:/dev:/usr/sbin/nologin sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/usr/sbin/nologin man:x:6:12:man:/var/cache/man:/usr/sbin/nologin lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin mail:x:8:8:mail:/var/mail:/usr/sbin/nologin ..... .....

[5]	Edit a file in a virtual machine.

root@dlp:~#  virt-edit -d debian13 /etc/fstab # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # systemd generates mount units based on this file, see systemd.mount(5). # Please run 'systemctl daemon-reload' after making changes here. # # <file system> <mount point> <type> <options> <dump> <pass> /dev/mapper/debian--vg-root / ext4 errors=remount-ro 0 1 # /boot was on /dev/vda1 during installation UUID=7fd24747-f3ac-4c8e-9c37-92cd30cc4220 /boot ext4 defaults 0 2 /dev/mapper/debian--vg-swap_1 none swap sw 0 0 /dev/sr0 /media/cdrom0 udf,iso9660 user,noauto 0 0

[6]	Display disk usage in a virtual machine.

root@dlp:~#  virt-df -d debian13 Filesystem 1K-blocks Used Available Use% debian13:/dev/sda1 954840 93308 795692 10% debian13:/dev/debian-vg/root 18421584 4445036 13015424 25%

[7]	Mount disk image of a virtual machine.

root@dlp:~#  guestmount -d debian13 -i /mnt root@dlp:~#  ll /mnt total 84 lrwxrwxrwx 1 root root 7 Aug 21 08:49 bin -> usr/bin drwxr-xr-x 4 root root 4096 Aug 21 08:55 boot drwxr-xr-x 4 root root 4096 Aug 21 08:49 dev drwxr-xr-x 125 root root 12288 Aug 21 09:59 etc drwxr-xr-x 3 root root 4096 Aug 21 08:55 home ..... .....