KVM: Difference between revisions
→Creating a RHEL 8.2 VM: Checking which port VNC is connected to |
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* Image management | * Image management | ||
** https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c02814204 | ** https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c02814204 | ||
* QEMU (System Emulation) | |||
** [https://www.qemu.org/docs/master/system/quickstart.html System Emulation User Guide] |
Revision as of 20:46, 16 October 2020
Kernel-based Virtual Machine. A hypervisor technology featuring tight integration to Linux kernel.
Installation
Creating a RHEL 8.2 VM
- Last tested on RHEL 8.2 (2020-06-30)
# virt-install --name=iqbal --vcpus=2 --memory=2048 --cdrom=/home/mhan/Downloads/rhel-8.2-x86_64-boot.iso --disk size=5 --os-variant=rhel8.2 --graphics vnc
Checking which port VNC is connected to
# virsh vncdisplay vm-name
Attaching a CD-ROM
# virsh attach-disk iqbal /var/lib/libvirt/boot/rhel-8.2-x86_64-boot.iso --type cdrom --mode readonly --target sda --targetbus sata
Installing on CentOS 7.5
- Tested on CentOS 7.5.1804
Install packages and start libvirtd
Install required packages:
# yum install qemu-kvm libvirt libvirt-python libguestfs-tools virt-install
Start the libvirtd service:
# systemctl enable libvirtd
# systemctl start libvirtd
Make sure KVM module loaded using lsmod command:
# lsmod | grep -i kvm
kvm_intel 178927 0
kvm 578558 1 kvm_intel
irqbypass 13503 1 kvm
Configuration
Configure bridged networking
Libvirtd configures a dhcpd-based network bridge by default. You can check in the following way:
# brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.525400f0c02d yes virbr0-nic
# virsh net-list
Name State Autostart Persistent
----------------------------------------------------------
default active yes yes
Default configuration allows all VMs to access other VMs but not the network that the host machine is on. You can check the private network created by default:
# virsh net-dumpxml default
<network>
<name>default</name>
<uuid>51beab57-eb0c-40b9-bb5e-957f31c1b489</uuid>
<forward mode='nat'>
<nat>
<port start='1024' end='65535'/>
</nat>
</forward>
<bridge name='virbr0' stp='on' delay='0'/>
<mac address='52:54:00:f0:c0:2d'/>
<ip address='192.168.122.1' netmask='255.255.255.0'>
<dhcp>
<range start='192.168.122.2' end='192.168.122.254'/>
</dhcp>
</ip>
</network>
Add the following line to /etc/sysconfig/network-scripts/ifconfig-enp3s0:
BRIDGE=br0
Create a new file /etc/sysconfig/network-scripts/ifcfg-br0:
DEVICE="br0"
# I am getting ip from DHCP server #
BOOTPROTO="dhcp"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
ONBOOT="yes"
TYPE="Bridge"
DELAY="0"
Restart the networking service:
# systemctl restart NetworkManager
Check with brctl command:
# brctl show
Create and set up a storage pool
Define a storage pool:
# virsh pool-define-as --name libvirt-images --type dir --target /var/lib/libvirt/images --source-format raw
Pool libvirt-images defined
Set it to autostart on boot:
# virsh pool-autostart libvirt-images
Pool libvirt-images marked as autostarted
Start for now:
# virsh pool-start libvirt-images
Pool libvirt-images started
Instantiation
Create a VM
This example creates an Ubuntu VM:
# virt-install --virt-type=kvm --name ubuntu1 --memory 4096 --vcpus 2 --os-variant ubuntu17.04 --os-type Linux --cdrom=/var/lib/libvirt/boot/ubuntu-18.04-desktop-amd64.iso --network bridge=br0,model=virtio --graphics vnc --disk path=/var/lib/libvirt/images/ubuntu1.qcow2,size=40,bus=virtio,format=qcow2
WARNING Unable to connect to graphical console: virt-viewer not installed. Please install the 'virt-viewer' package.
WARNING No console to launch for the guest, defaulting to --wait -1
Starting install...
Allocating 'ubuntu1.qcow2' | 40 GB 00:00:00
Domain installation still in progress. Waiting for installation to complete.
Connect via VNC and complete installation
Get port number for VNC:
# virsh dumpxml ubuntu1 | grep vnc
<graphics type='vnc' port='5900' autoport='yes' listen='127.0.0.1'>
Create a SSH tunnel:
$ ssh mhan@chara -L 5900:127.0.0.1:5900
and then use a VNC client to connect to 127.0.0.1 (aka localhost) with port of 5900.
Mount guest image
Make sure to have right packages:
# yum install libguestfs-tools
Mount to /mnt:
# guestmount -a /var/lib/libvirt/images/ubuntu1.qcow2 -m /dev/sda1 /mnt
Unmount /mnt:
# guestunmount /mnt
Links
- https://www.cyberciti.biz/faq/how-to-install-kvm-on-centos-7-rhel-7-headless-server/
- https://www.thegeekstuff.com/2014/10/linux-kvm-create-guest-vm/
- https://www.techotopia.com/index.php/Installing_a_KVM_Guest_OS_from_the_Command-line_(virt-install)
- https://www.tecmint.com/kvm-management-tools-to-manage-virtual-machines/
- https://www.server-world.info/en/note?os=Ubuntu_18.04&p=kvm&f=2
- Image management
- QEMU (System Emulation)