Virsh commands cheatsheet to manage KVM guest virtual machines

This is a comprehensive virsh commands cheatsheet: Virsh is a management user interface for virsh guest domains. Virsh can be used to create, pause, restart, and shutdown domains. In addition, virsh can be used to list current domains available in your Virtualization hypervisor platform.

Virsh interacts with Libvirt which is a library aimed at providing a long-term stable C API. It currently supports Xen, QEMU, KVM, LXC, OpenVZ, VirtualBox and VMware ESX.

For installation guide of KVM on most Linux distributions, check the link below:

• Install KVM on CentOS / RHEL / Ubuntu / Debian / SLES / Arch Linux

Virsh commands cheatsheet

In this virsh commands cheatsheet, I’ll show you most used virsh commands to manage Guest Virtual Machines running on KVM or Xen Hypervisor.

The basic structure of most virsh usage is:

$ virsh [OPTION]... <command> <domain> [ARG]...

Virsh display node information:

This is the first item on our virsh commands cheatsheet. This displays the host node information and the machines that support the virtualization process.

$ sudo virsh nodeinfo 
CPU model:           x86_64
CPU(s):              8
CPU frequency:       2200 MHz
CPU socket(s):       1
Core(s) per socket:  4
Thread(s) per core:  2
NUMA cell(s):        1
Memory size:         12238908 KiB

List os variants

To get the value for the --os-variant run the following command:

$ osinfo-query os

Virsh list all domains

To list both inactive and active domains, use the command:

$ sudo virsh list --all
 Id    Name                           State
 ----------------------------------------------------
-     admin                          shut off
-     cloudstack                     shut off
-     hyperv                         shut off
-     ipa                            shut off
-     katello                        shut off
-     node1                          shut off
-     node2                          shut off
-     node3                          shut off
-     server1                        shut off
-     server2                        shut off
-     test                           shut off
-     ubuntu14.04                    shut off
-     win12k                         shut off
-     xen                            shut off
-     zenoss                         shut off

List only active domains

To list only active domains with virsh command, use:

$ sudo virsh list
 Id    Name                           State
 ----------------------------------------------------

Virsh rename domain

Syntax:

virsh domrename currentname  newname

List available domains

$ sudo virsh list --all
 Id   Name         State
----------------------------
 4    centos-8.2   running

$ sudo virsh domrename centos-8.2 apacheserver01
Domain successfully renamed

We’ve changed the name of the domain from centos-8.2 to apacheserver01

Virsh change domain boot disk

Edit the domain by passing its name:

$ sudo virsh  edit domain

Scroll down until <devices> section and modify values for the line below:

<source file=''/>

Example

<source file='/var/lib/libvirt/images/apacheserver01.qcow2'/>

Virsh start vm

This is an example on how to use virsh command to start a guest virtual machine. We’re going to start test domain displayed above:

$ sudo virsh start test
Domain test started

$ sudo virsh list      
 Id    Name                           State
 ----------------------------------------------------
  3     test                           running

Virsh autostart vm

To set a vm to start automatically on system startup, do:

$ sudo virsh autostart test
Domain test marked as autostarted

$ sudo virsh dominfo test  
Id:             9
Name:           test
UUID:           a943ed42-ba62-4270-a41d-7f81e793d754
OS Type:        hvm
State:          running
CPU(s):         2
CPU time:       144.6s
Max memory:     2048 KiB
Used memory:    2048 KiB
Persistent:     yes
Autostart:      enable
Managed save:   no
Security model: none
Security DOI:   0

Keep an eye on the option Autostart: enable.

Virsh autostart disable

To disable autostart feature for a vm:

 $ sudo virsh autostart --disable test
 Domain test unmarked as autostarted

 $ sudo virsh dominfo test
 Id:             -
 Name:           test
 UUID:           a943ed42-ba62-4270-a41d-7f81e793d754
 OS Type:        hvm
 State:          shut off
 CPU(s):         2
 Max memory:     2048 KiB
 Used memory:    2048 KiB
 Persistent:     yes
 Autostart:      disable
 Managed save:   no
 Security model: none
 Security DOI:   0

Virsh stop vm, virsh shutdown vm

To shutdown a running vm gracefully use:

$ sudo virsh shutdown test
Domain test is being shutdown

$ sudo virsh list
 Id    Name                           State
 ----------------------------------------------------

Virsh force shutdown vm

You can do a forceful shutdown of active domain using the command:

$ sudo virsh destroy test

Virsh stop all running vms

In case you would like to shutdown all running domains, just issue the command below:

for i in `sudo virsh list | grep running | awk '{print $2}'` do
    sudo virsh shutdown $i
done

Virsh reboot vm

To restart a vm named test, the command used is:

sudo virsh reboot test

Virsh remove vm

To cleanly remove a vm including its storage columes, use the commands shown below. The domain test should be replaced with the actual domain to be removed.

sudo virsh destroy test 2> /dev/null
sudo virsh undefine  test
sudo virsh pool-refresh default
sudo virsh vol-delete --pool default test.qcow2

In this example, storage volume is named /var/lib/libvirt/images/test.qcow2

You can also use undefine with–remove-all-storage option:

sudo virsh undefine test --remove-all-storage

Virsh create a vm

If you would like to create a new virtual machine with virsh, the relevant command to use is virt-install. This is crucial and can’t miss on virsh commands cheatsheet arsenal. The example below will install a new operating system from CentOS 7 ISO Image.

sudo virt-install \
  --name centos7 \
  --description "Test VM with CentOS 7" \
  --ram=1024 \
  --vcpus=2 \
  --os-type=Linux \
  --os-variant=rhel7 \
  --disk path=/var/lib/libvirt/images/centos7.qcow2,bus=virtio,size=10 \
  --graphics none \
  --location $HOME/iso/CentOS-7-x86_64-Everything-1611.iso \
  --network bridge:virbr0 \
  --console pty,target_type=serial -x 'console=ttyS0,115200n8 serial'

Virsh connect to vm console

To connect to the guest console, use the command:

sudo virsh console test

This will return a fail message if an active console session exists for the provided domain. To solve this run:

sudo virsh console test --force

Virsh edit vm xml file

To edit a vm xml file, use:

export EDITOR=vim
sudo virsh edit test

To use nano text editor

export EDITOR=nano
sudo virsh edit test

Virsh suspend vm, virsh resume vm

To suspend a guest called testwith virsh command, run:

$ sudo virsh suspend test
Domain test suspended

NOTE: When a domain is in a suspended state, it still consumes system RAM. Disk and network I/O will not occur while the guest is suspended.

Resuming a guest vm:

To restore a suspended guest with virsh using the resume option:

$ sudo virsh resume test
Domain test resumed

Virsh save vm

To save the current state of a vm to a file using the virsh command :

The syntax is:

$ sudo virsh save test test.saved
Domain test saved to test.save

$ ls -l test.save
-rw------- 1 root root 328645215 Mar 18 01:35 test.saved

Restoring a saved vm

To restore saved vm from the file:

$ sudo virsh restore test.save 
Domain restored from test.save

$ sudo virsh list
 Id    Name                           State
 ----------------------------------------------------
  7     test                           running

Virsh Manage Volumes

Here we’ll cover how to create a storage volume , attach it to a vm , detach it from a vm and how to delete a volume.

Virsh create volume

To create a 2GB volume named test_vol2 on the default storage pool, use:

$ sudo virsh vol-create-as default test_vol2.qcow2 2G
Vol test_vol2.qcow2 created

$ sudo du -sh /var/lib/libvirt/images/test_vol2.qcow2
2.0G/var/lib/libvirt/images/test_vol2.qcow2

• default: Is the pool name.
• test_vol2: This is the name of the volume.
• 2G: This is the storage capacity of the volume.

List volumes

sudo virsh vol-list --pool default
sudo virsh vol-list --pool images

Virsh attach a volume to vm

To attach created volume above to vm test, run:

sudo virsh attach-disk --domain test \
  --source /var/lib/libvirt/images/test_vol2.qcow2 \
  --persistent --target vdb

• --persistent: Make live change persistent
• --target vdb: Target of a disk device

You can confirm that the volume was added to the vm as a block device /dev/vdb

$ ssh test
Last login: Fri Mar 17 19:30:54 2017 from gateway
[root@test ~]# 

[root@test ~]# lsblk --output NAME,SIZE,TYPE
NAME              SIZE TYPE
sr0              1024M rom
vda                10G disk
├─vda1              1G part
└─vda2              9G part
  ├─cl_test-root    8G lvm
    └─cl_test-swap    1G lvm
    vdb                 2G disk

Example showing how to create and attach secondary virtual disk:

export VM=test-vm
sudo qemu-img create -f qcow2 /var/lib/libvirt/images/${VM}-disk2.qcow2 20g

sudo virsh attach-disk  \
  --source /var/lib/libvirt/images/${VM}-disk2.qcow2 \
  --target vdb \
  --persistent \
  --subdriver qcow2 \
  --driver qemu \
  --type disk

Virsh detach volume on vm

To detach above volume test_vol2 from the vm test:

$ sudo virsh detach-disk --domain test --persistent --live --target vdb
Disk detached successfully

$ ssh test
Last login: Sat Mar 18 01:52:33 2017 from gateway
[root@test ~]#
[root@test ~]# lsblk --output NAME,SIZE,TYPE
NAME SIZE TYPE
sr0 1024M rom
vda 10G disk
├─vda1 1G part
└─vda2 9G part
├─cl_test-root 8G lvm
└─cl_test-swap 1G lvm
[root@test ~]#

You can indeed confirm from this output that the device /dev/vdb has been detached

Please note that you can directly grow disk image for the vm using qemu-img command, this will look something like this:

sudo qemu-img resize /var/lib/libvirt/images/test.qcow2 +1G

The main shortcoming of above command is that you cannot resize an image which has snapshots.

Virsh delete volume

List storage pools:

$ sudo virsh pool-list
 Name     State    Autostart
------------------------------
 default   active   yes

To delete volume with virsh command, use:

# List volumes
$ sudo virsh vol-list --pool default

$ sudo virsh vol-delete test_vol2.qcow2 --pool default
Vol test_vol2.qcow2 deleted

$ sudo virsh pool-refresh default
Pool default refreshed

$ sudo virsh vol-list default
 Name                 Path                                    
 ------------------------------------------------------------------------------
admin.qcow2          /var/lib/libvirt/images/admin.qcow2     
cloudstack.qcow2     /var/lib/libvirt/images/cloudstack.qcow2
ipa.qcow2            /var/lib/libvirt/images/ipa.qcow2       
katello.qcow2        /var/lib/libvirt/images/katello.qcow2   
node1.qcow2          /var/lib/libvirt/images/node1.qcow2     
node2.qcow2          /var/lib/libvirt/images/node2.qcow2     
node3.qcow2          /var/lib/libvirt/images/node3.qcow2     
test.qcow2           /var/lib/libvirt/images/test.qcow2      
ubuntu14.04.qcow2    /var/lib/libvirt/images/ubuntu14.04.qcow2
zenoss.qcow2         /var/lib/libvirt/images/zenoss.qcow2  

Virsh Manage Snapshots

In this second last section of managing kvm guest machines with virsh command, we’ll have a look at managing VM snapshots.

Virsh Create Snapshot for a vm

Let’s create a snapshot for our test vm.

sudo virsh snapshot-create-as \
  --domain test \
  --name "test_vm_snapshot1" \
  --description "test vm snapshot 1-working"

Virsh list Snapshots for a vm

To list available snapshots for a vm, use:

$ sudo virsh snapshot-list test
 Name                 Creation Time             State
 ------------------------------------------------------------
  1489689679           2017-03-16 21:41:19 +0300 shutoff
  test_fresh           2017-03-16 22:11:48 +0300 shutoff
  test_vm_snapshot1    2017-03-18 02:15:58 +0300 running

Virsh display info about a snapshot:

To retrieve more information about a domain, use:

$ sudo virsh snapshot-info --domain test --snapshotname test_vm_snapshot1
Name:           test_vm_snapshot1
Domain:         test
Current:        yes
State:          running
Location:       internal
Parent:         test_fresh
Children:       0
Descendants:    0
Metadata:       yes

Virsh revert vm snapshot

Here we’ll create another snapshot called test_vm_snapshot2, then revert to snapshot test_vm_snapshot1

$ sudo virsh snapshot-create-as \
  --domain test --name "test_vm_snapshot2" \
  --description "test vm snapshot 2-working"

Domain snapshot test_vm_snapshot2 created

Let’s revert the snapshot we created before:

$ sudo virsh snapshot-list test
 Name                 Creation Time             State
 ------------------------------------------------------------
  1489689679           2017-03-16 21:41:19 +0300 shutoff
  test_fresh           2017-03-16 22:11:48 +0300 shutoff
  test_vm_snapshot1    2017-03-18 02:15:58 +0300 running
  test_vm_snapshot2    2017-03-18 02:23:29 +0300 running

$ sudo virsh snapshot-revert --domain test  --snapshotname test_vm_snapshot1  --running

Virsh delete snapshot

Let’s delete the two snapshots we created:

$ sudo  virsh snapshot-delete --domain test --snapshotname  test_vm_snapshot2
Domain snapshot test_vm_snapshot2 deleted

$ sudo  virsh snapshot-delete --domain test --snapshotname  test_vm_snapshot1
Domain snapshot test_vm_snapshot1 deleted

$ sudo virsh snapshot-list test
 Name                 Creation Time             State
 ------------------------------------------------------------
  1489689679           2017-03-16 21:41:19 +0300 shutoff
  test_fresh           2017-03-16 22:11:48 +0300 shutoff

Virsh clone a vm

Domain with devices to clone must be paused or shutoff. So let’s shut it down:

$ sudo virsh destroy test
Domain test destroyed

Then clone a vm, do it as shown below:

$ sudo virt-clone --connect qemu:///system \
--original test \
--name test_clone \
--file /var/lib/libvirt/images/test_clone.qcow2 

Allocating 'test_clone.qcow2'       |  10 GB  00:00:06

Clone 'test_clone' created successfully.

$ sudo virsh dominfo test_clone
Id:             -
Name:           test_clone
UUID:           be0621fd-51b5-4d2b-a05c-ce76e59baafa
OS Type:        hvm
State:          shut off
CPU(s):         1
Max memory:     1048576 KiB
Used memory:    1048576 KiB
Persistent:     yes
Autostart:      disable
Managed save:   no
Security model: none
Security DOI:   0

Virsh manage VM vcpus

This virsh commands cheatsheet section covers how to add additional virtual cpus to a virtual machine:

sudo virsh setvcpus --domain test --maximum 2 --config
sudo virsh setvcpus --domain test --count 2 --config
sudo virsh shutdown test
sudo virsh start test

Confirm that the number of vcpu has changed, the previous was 1, the current value is 2:

$ sudo virsh dominfo test
Id:             -
Name:           test
UUID:           a943ed42-ba62-4270-a41d-7f81e793d754
OS Type:        hvm
State:          shut off
CPU(s):         2
Max memory:     1048576 KiB
Used memory:    1048576 KiB
Persistent:     yes
Autostart:      disable
Managed save:   no
Security model: none
Security DOI:   0

Virsh manage VM memory

Also on virsh commands cheatsheet is managing RAM with virsh. To adjust the total ram used by the guest operating system, the following commands are used:

# In MB
sudo virsh setmaxmem test 2048 --config
sudo virsh setmem test 2048 --config
sudo virsh shutdown test
sudo virsh start test

# Same in GB
sudo virsh setmaxmem test 16G --config
sudo virsh setmem test 16G --config
sudo virsh shutdown test
sudo virsh start test

Check domain info to confirm the current RAM allocated to the VM.

$ sudo virsh dominfo test                     
Id:             9
Name:           test
UUID:           a943ed42-ba62-4270-a41d-7f81e793d754
OS Type:        hvm
State:          running
CPU(s):         2
CPU time:       70.7s
Max memory:     2048 KiB
Used memory:    2048 KiB
Persistent:     yes
Autostart:      disable
Managed save:   no
Security model: none
Security DOI:   0

Notice that the current ram allocated to the VM is 2048

Mount Virtual Disk

You can mount a virtual disk on KVM for offline administration. For this, we have a ready article which you can reference from the link below:

• How to mount VM virtual disk on KVM hypervisor

ls a directory in a virtual machine

To ls a directory on a running VM, you need the libguestfs-tools installed.

The run:

$ sudo virt-ls -l -d <domain>  <directory>

E.g

$ sudo virsh list
 Id Name State
----------------------------------------------------
 10 allot_netxplorer_01 running
 19 sg-ve-01 running

$ sudo virt-ls -l -d allot_netxplorer_01 /root
total 28
dr-xr-x---. 2 root root 135 Mar 22 14:26 .
dr-xr-xr-x. 17 root root 224 Mar 21 10:37 ..
-rw-------. 1 root root 385 Mar 22 14:26 .bash_history
-rw-r--r--. 1 root root 18 Dec 29 2013 .bash_logout
-rw-r--r--. 1 root root 176 Dec 29 2013 .bash_profile
-rw-r--r--. 1 root root 176 Dec 29 2013 .bashrc
-rw-r--r--. 1 root root 100 Dec 29 2013 .cshrc
-rw-r--r--. 1 root root 129 Dec 29 2013 .tcshrc
-rw-------. 1 root root 1447 Mar 21 10:38 anaconda-ks.cfg

Common options are:

-R |--recursive --> Recursive listing
-h |--human-readable --> Human-readable sizes in output
-d |--domain guest --> Add disks from libvirt guest
-l |--long --> Long listing

cat a file in a virtual machine

You can as well cat a file without doing ssh to the VM or accessing it via the console. You need the libguestfs tools installed on the hypervisor for this to work.

$ sudo virt-cat -d <domain>  <file_path>
$ sudo virt-cat -d sg-ve-01 /etc/redhat-release
CentOS Linux release 7.1.1503 (Core)

$ sudo dufo virt-cat -d sg-ve-01 /etc/redhat-release > check_os
$ cat check_os 
CentOS Linux release 7.1.1503 (Core)

Edit a file in a virtual machine

After installing libguestfs-tools on the hypervisor, use the virsh-edit command:

sudo virt-edit -d sg-ve-01 /etc/hosts

Display VM disk usage

Use the virt-df command:

$ sudo virt-df -d sg-ve-01 
Filesystem 1K-blocks Used Available Use%sg-ve-01:/dev/sda1 20469760 3954792 16514968 20%
sg-ve-01:/dev/sda2 27739924 173828 27566096 1%

List filesystems, partitions, block devices, LVM
in a virtual machine or disk image

$ sudo virt-filesystems -l -d sg-ve-01
Name Type VFS Label Size Parent
/dev/sda1 filesystem xfs - 20971520000 -
/dev/sda2 filesystem xfs - 28419555328 -

$ sudo virt-filesystems -l -h -d sg-ve-01
Name Type VFS Label Size Parent
/dev/sda1 filesystem xfs - 20G -
/dev/sda2 filesystem xfs - 26G -

$ sudo virt-filesystems -l -h -d sg-ve-01 --partitions
Name       Type    MBR Size Parent
/dev/sda1 partition 83 20G /dev/sda
/dev/sda2 partition 83 26G /dev/sda
/dev/sda3 partition 82 4.0G /dev/sda

$ sudo virt-filesystems -d sg-ve-01 --all --long --uuid -h
Name Type VFS Label MBR Size Parent UUID
/dev/sda1 filesystem xfs - - 20G - 97074514-612e-4d1c-8433-935dbb3ec775
/dev/sda2 filesystem xfs - - 26G - 8cc9e0cd-282d-46a4-9a37-069dfb93c4f2
/dev/sda3 filesystem swap - - 4.0G - ad7dcd49-fe1a-4938-8600-f7299a59c57a
/dev/sda1 partition - - 83 20G /dev/sda -
/dev/sda2 partition - - 83 26G /dev/sda -
/dev/sda3 partition - - 82 4.0G /dev/sda -
/dev/sda device - - - 100G - -

Show stats of virtualized domains

Use virt-top to display stats of virtualized domains. You can filter by CPU, RAM e.t.c and save the output to a CSV file.

$ virt-top
$ sudo virt-top --csv file.csv

You can also send debug and error messages to a filename. To send error messages to syslog you can do:

sudo virt-top --debug >(logger -t virt-top)

Enable VNC on existing VM instance

List domains on KVM

$ virsh list --all

Stop the instance

virsh shutdown <domain-name>

Edit the VM domain config using virsh edit command.

$ virsh edit <domain-name>

Add below XML contents within <devices> block (Accessible from outside)

<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'>
  <listen type='address' address='0.0.0.0'/>
</graphics>

Local loopback listen – (Accessible only locally on the host)

<graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1' keymap='en-us'>
  <listen type='address' address='127.0.0.1'/>
</graphics>

Display log files from a virtual machine

“virt-log” is a command line tool to display the log files from the named virtual machine (or disk image). This tool understands and displays both plain text log files (eg. /var/log/messages) and binary formats such as the systemd journal.

sudo virt-log -d <domain> | less
sudo virt-log -d <domain> | grep 'dhclient.*bound to'

Virsh Manage networking

To wrap up our virsh commands cheatsheet content, please read my previous article:

• Configure KVM Networking With virsh, nmcli and brctl in Linux

Conclusion

Our virsh commands cheatsheet is now complete. In our next tutorial on virsh commands, I’ll share with you my bash functions that come in handy when managing Guest machines on KVM.

I would like to thank you for taking your time to read this post. Please share and comment if you have any issue.

More guides on Virtualization:

• Enable Nested Virtualization on Xen | XCP-ng Virtual Machine
• How To Deploy and Use KubeVirt on Minikube
• Using Dnsmasq DHCP Server in Proxmox for VMs IP