How to do it...

The following steps outline the process of listing, starting, and stopping KVM instances using the virsh command:

1. List all instances in all states:

root@kvm:~# virsh list --all
 Id Name State
----------------------------------------------------
 - kvm1 shut off
root@kvm:~#

1. Start the newly defined instance and verify its status:

root@kvm:~# virsh start kvm1
Domain kvm1 started

root@kvm:~#
root@kvm:~# virsh list --all
 Id Name State
----------------------------------------------------
 1 kvm1 running

root@kvm:~#

1. Examine the running process for the virtual machine:

root@kvm:~# pgrep -lfa qemu
1686 /usr/bin/qemu-system-x86_64 -name kvm1 -S -machine pc-i440fx-trusty,accel=kvm,usb=off -m 1024 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid a9dfd1a1-7dd1-098e-a926-db9526785a9e -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/kvm1.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/tmp/debian.img,if=none,id=drive-ide0-0-0,format=raw -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -netdev tap,fd=24,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:ce:dd:f2,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc 146.20.141.158:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4
root@kvm:~#

1. Terminate the VM and ensure its status changed from running to shut off:

root@kvm:~# virsh destroy kvm1
Domain kvm1 destroyed

root@kvm:~# virsh list --all
 Id Name State
----------------------------------------------------
 - kvm1 shut off

root@kvm:~#

1. Remove the instance definition:

root@kvm:~# virsh undefine kvm1
Domain kvm1 has been undefined

root@kvm:~# virsh list --all
 Id Name State
----------------------------------------------------

root@kvm:~#