Category: Virtualization

Install virt-manager on Ubuntu
virt-manager is a GUI tool used to manage KVM virtial machines. To install virt-manager on Ubuntu, run
```
apt install virt-manager
```
September 5, 2019
Clone VM on VMware ESXi using vmkfstools
Free version of VMware ESXi don’t provide option to clone virtual machine. If you want to clone a VM, you need to purchase expensive vSphere license.

There is a work around for this, you need to clone disk of an existing Virtual machine using vmkfstools.

To make clone of a VM disk, SSH into your VMWare ESXi server as user root. Then create clone of disk with
```
vmkfstools -i "source.vmdk" "destination.vmdk"
```
For new VM, i created a directory. Path to datastore directory may be differnt on your server, you can find it using “df -h” command and checking the file system.
```
mkdir /vmfs/volumes/disk2/ubuntu-clone/
```
Shutdown the Virtual Machine you want to clone the disk from. Run
```
[root@ns3048991:~] vmkfstools -i "/vmfs/volumes/disk2/Ubuntu/Ubuntu.vmdk" "/vmfs/volumes/disk2/ubuntu-clone/ubuntu-clone.vmdk"
Destination disk format: VMFS zeroedthick
Cloning disk '/vmfs/volumes/disk2/Ubuntu/Ubuntu.vmdk'...
Clone: 100% done.
[root@ns3048991:~] 
```
In screenshot below, i first tried to clone with out creating destination folder. That resulted in error. After creating destination folder, vmkfstools command worked.

Creating VM using cloned disk

Login to VMware ESXi web interface. Create a new VM. On the step where you select hardware, delete the existing Disk. Add a new disk, browse and select the newly created clone disk. In this case – “/vmfs/volumes/disk2/ubuntu-clone/ubuntu-clone.vmdk”

Once the VM creation is finished, you will be able to start the new VM. You can create a VM, then use it as the template for creating new virtual machines.

See VMWare
September 4, 2019

virsh

virsh command is used to manage KVM vps. It is part of libvirt package.

To list KVM virtual machines, run

virsh list

Start a VM

virsh start VM_ID

To shutdown a VM, run

virsh shutdown VM_ID

To delete a VM, run

virsh shutdown VM_ID

Connect to a Remote Server

virsh --connect qemu+ssh://[email protected]/system

You need SSH Key based authentication setup.

List All VM

boby@fwhlin:~ $ virsh list --all
 Id    Name                           State
----------------------------------------------------
 -     vm1                            shut off

boby@fwhlin:~ $

List All Running VM

[root@server70 ~]# virsh list
 Id    Name                           State
----------------------------------------------------
 1     vm10                           running
 3     vm12                           running
 5     vm15                           running
 7     vm17                           running
 12    vm16                           running

[root@server70 ~]#

Get Info About a VM

virsh dominfo VM_NAME

example

[root@server70 ~]# virsh dominfo vm18
Id:             10
Name:           vm18
UUID:           b6c3a3d8-d96a-c3fa-1fad-04aff28e476a
OS Type:        hvm
State:          running
CPU(s):         2
CPU time:       422.9s
Max memory:     524288 KiB
Used memory:    524288 KiB
Persistent:     yes
Autostart:      disable
Managed save:   no
Security model: none
Security DOI:   0

[root@server70 ~]#

Change the Memory of a VM

virsh dumpxml vm18 > vm18.xml
virsh shutdown vm18

vi vm18.xml

Find

<memory unit='KiB'>524288</memor<memory unit='KiB'>524288</memory>
<currentMemory unit='KiB'>524288</currentMemory>

To change Memory to 1 GB, Replace it with

<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>

Load configuration

virsh define vm18.xml

Example

[root@server70 ~]# virsh define vm18.xml
Domain vm18 defined from vm18.xml

[root@server70 ~]#

Start VM

virsh start vm18

[root@server70 ~]# virsh start vm18
Domain vm18 started

[root@server70 ~]#

See kvm

August 31, 2019

LXD container snapshot and restore

lxc allow you to take snapshot, restore snapshot of a container.

Here we create a snapshot, then delete the /etc folder from the container. Now the container is useless. Restore the container from snapshot to get it work again.

root@UNUSED:~# lxc snapshot my-vm-2 my-vm-2-snap1
root@UNUSED:~# lxc exec my-vm-2 -- rm -rf /etc
root@UNUSED:~# lxc exec my-vm-2 -- bash
I have no name!@my-vm-2:~# ls -l / | grep etc
I have no name!@my-vm-2:~# exit
root@UNUSED:~# lxc restore my-vm-2 my-vm-2-snap1
root@UNUSED:~# lxc exec my-vm-2 -- bash
root@my-vm-2:~# ls -l / | grep etc
drwxr-xr-x  89 root   root    4096 Aug 27 07:06 etc
root@my-vm-2:~# exit
root@UNUSED:~#

August 31, 2019

Install LXD on Ubuntu

To create LXD containers, run

lxc launch ubuntu:22.04 VM-NAME-HERE
lxc launch ubuntu:24.04 VM-NAME-HERE
lxc launch images:almalinux/8 VM-NAME-HERE
lxc launch images:almalinux/9 VM-NAME-HERE
lxc launch images:amazonlinux/2023 VM-NAME-HERE
lxc launch images:archlinux VM-NAME-HERE
lxc launch images:centos/9-Stream VM-NAME-HERE
lxc launch images:debian/11 VM-NAME-HERE
lxc launch images:debian/12 VM-NAME-HERE
lxc launch images:fedora/39 VM-NAME-HERE
lxc launch images:fedora/40 VM-NAME-HERE
lxc launch images:oracle/8 VM-NAME-HERE
lxc launch images:oracle/9 VM-NAME-HERE

LXD is a tool to manage LXC (Linux Containers). lxd allow you to create and manage lightweight Linux containers, it is like docker, but more like an actual virtual machine. LXD is more user-friendly than using LXC directly, has more features like clustering of servers.

On Ubuntu/Debian, run

apt install -y lxd lxd-client

Before you start using lxd, run

lxd init --auto --storage-backend=dir

lxd init

Just press enter for all questions. Defaults should work. lxd is a demon, only used one time during “lxd init”. After this, you will be using lxc command for everything.

Example

root@b24:~# lxd init
Would you like to use LXD clustering? (yes/no) [default=no]: 
Do you want to configure a new storage pool? (yes/no) [default=yes]: 
Name of the new storage pool [default=default]: 
Name of the storage backend to use (dir, lvm, ceph, btrfs) [default=btrfs]: 
Create a new BTRFS pool? (yes/no) [default=yes]: 
Would you like to use an existing empty block device (e.g. a disk or partition)? (yes/no) [default=no]: 
Size in GB of the new loop device (1GB minimum) [default=30GB]: 
Would you like to connect to a MAAS server? (yes/no) [default=no]: 
Would you like to create a new local network bridge? (yes/no) [default=yes]: 
What should the new bridge be called? [default=lxdbr0]: 
What IPv4 address should be used? (CIDR subnet notation, “auto” or “none”) [default=auto]: 
What IPv6 address should be used? (CIDR subnet notation, “auto” or “none”) [default=auto]: none
Would you like the LXD server to be available over the network? (yes/no) [default=no]: 
Would you like stale cached images to be updated automatically? (yes/no) [default=yes] 
Would you like a YAML "lxd init" preseed to be printed? (yes/no) [default=no]: 
root@b24:~#

When it ask for IPv6, I selected “none”, everything else is the default.

To create a container, run

lxc launch ubuntu:22.04 vm-1

Create CentOS container

lxc launch images:centos/7 vm-2

Create Debian 10 container

lxc launch images:debian/10 vm-3

To list all containers, run

lxc ls

To stop a VM, run

lxc stop VM-NAME

To start VM,

lxc start VM-NAME

To see information about a container

lxc info VM-NAME

Folders

/var/snap/lxd/

To see storage, run

lxc storage ls

All containers share the following disk image.

/var/snap/lxd/common/lxd/disks/default.img

August 30, 2019

lxc
LXC is Linux Container, allows you to run lightweight virtual servers on your computer.

It is better use LXD instead of LXC. LXD provides a much easier-to-use interface to LXC.
To install lxc, run
```
apt install -y lxc
```
To create a VM, use
```
lxc-create -t download -n first-vm
```
To list VM, use the command lxc-ls
```
root@UNUSED:~# lxc-ls
first-vm 
root@UNUSED:~# lxc-ls -f
NAME     STATE   AUTOSTART GROUPS IPV4      IPV6 UNPRIVILEGED 
first-vm RUNNING 0         -      10.0.3.26 -    false        
root@UNUSED:~#
```
To start a VM, run
```
lxc-start VM_NAME
```
To login to a VM, run
```
lxc-attach VM_NAME
```
lxc config files
```
/etc/lxc/default.conf
/etc/lxc/lxc-usernet
/var/lib/lxc
```
August 26, 2019
Create lxc container with lxc-create
lxc-create is used to create lxc container. To create a container, run
```
lxc-create -t download -n CONTAINER_NAME_HERE
```
This will list all available containers. You can select the OS you want to use.

To specify OS, you can use the following examples
```
lxc-create -t download -n mycontainer-1 -- -d ubuntu -r focal -a amd64
lxc-create -t download -n mycontainer-2 -- -d debian -r buster -a amd64
```
To list all containers, run
```
lxc-ls -f
```
To start a container, run
```
lxc-start NAME
```
To connect to a container, use the command
```
lxc-attach NAME
```
Example
```
root@b24:~# lxc-attach boby2
root@boby2:~# cat /etc/*issue
Debian GNU/Linux 10 \n \l

root@boby2:~# 
```
To delete a container, run
```
lxc-destroy NAME
```
See lxc
August 26, 2019
xe vm-list
xe vm-list command is used to list all VM on a Xen Server.
```
xe vm-list
```
See Xen
March 17, 2019
Xen

xe vm-list
Manage XenServer from command line with xe

xsconsole

March 17, 2019

Delete a disk partition in VMWare ESXI

To delete a partition in VMWare ESXI, you can use command

partedUtil

First find out all disks available on your server using command

ls /vmfs/devices/disks/

On my server, it show following

[root@ns3048991:~] ls /vmfs/devices/disks/
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________    vml.01000000004e34473354343459202020202020202020202020484753542048
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:1  vml.01000000004e34473354343459202020202020202020202020484753542048:1
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:2  vml.01000000004e34473354343459202020202020202020202020484753542048:2
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:3  vml.01000000004e34473354343459202020202020202020202020484753542048:3
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:5  vml.01000000004e34473354343459202020202020202020202020484753542048:5
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:6  vml.01000000004e34473354343459202020202020202020202020484753542048:6
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:7  vml.01000000004e34473354343459202020202020202020202020484753542048:7
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:8  vml.01000000004e34473354343459202020202020202020202020484753542048:8
t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:9  vml.01000000004e34473354343459202020202020202020202020484753542048:9
t10.ATA_____HGST_HUS726020ALA610____________________N4G3TSMY____________    vml.01000000004e34473354534d59202020202020202020202020484753542048
t10.ATA_____HGST_HUS726020ALA610____________________N4G3TSMY____________:1  vml.01000000004e34473354534d59202020202020202020202020484753542048:1
[root@ns3048991:~]

I want to delete the partition

t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________:3  vml.01000000004e34473354343459202020202020202020202020484753542048:3

To do this, i run

partedUtil delete "/vmfs/devices/disks/t10.ATA_____HGST_HUS726020ALA610____________________N4G3T44Y____________" 3

Here is help for partedUtil

[root@ns3048991:~] partedUtil
Not enough arguments

Usage: 
 Get Partitions : get  
 Set Partitions : set  ["partNum startSector endSector type attr"]* 
 Delete Partition : delete  
 Resize Partition : resize    
 Get Partitions : getptbl  
 Set Partitions : setptbl   ["partNum startSector endSector type/guid attr"]* 
 Fix Partition Table : fix  
 Create New Label (all existing data will be lost): mklabel   
 Show commonly used partition type guids : showGuids 
 Get usable first and last sectors : getUsableSectors  
 Fix GPT Table interactively : fixGpt  
 Show Partition Information : partinfo   
 Add Partition Information : add   ["partNum startSector endSector type/guid attr"] 

[root@ns3048991:~]

March 4, 2019