Linux KVM related tutorial/FAQ

How to create VM using the qcow2 image file in KVM

last updated November 17, 2018 in CentOS, Debian / Ubuntu, Linux, Linux KVM, Suse

I have image.qcow2 file. How do I install the qcow2 image provided in the qcow2 format? How do I create Linux KVM VM from provided image (say image.qcow2) file?

KVM forward ports to guests VM with UFW on Linux

last updated July 30, 2018 in CentOS, Debian / Ubuntu, Iptables, Linux, Linux KVM

My Debian/Ubuntu/CentOS Linux server using KVM as a hypervisor. I would like to forward ports to guests VM with UFW iptables. How do I forward ports on a Linux server running libvirt/KVM to specified ports on VM’s, when using NAT?

Slow performance issues of OpenBSD or FreeBSD KVM guest on Linux

last updated July 22, 2018 in CentOS, Linux KVM, RedHat and Friends, Troubleshooting

I run a couple of OpenBSD and FreeBSD guest/virtual machines under KVM. My server has 32GB ram and 4C/8T Intel Xeon CPU. Everything was working fine until recent CentOS Linux 7 kernel update. After a fresh reboot of my CentOS 7 Linux box OpenBSD and FreeBSD machine become very slow and after 24 hours stop responding to the network request. How can I solve significant performance problems with BSD family of oses running on CentOS 7 KVM?

How to reset a KVM clone virtual Machines with virt-sysprep on Linux

last updated October 13, 2018 in CentOS, Debian / Ubuntu, Linux KVM, RedHat and Friends, Suse, Virtualization

I know how to clone a KVM VM. Once cloned I would like to reset cloned VM. How do I reset, unconfigure or customize a virtual machine so clones can be made? How can I reset a KVM clone virtual Machines with virt-sysprep command on a Linux server based hypervisor?

Linux list a KVM vm guest using virsh command

last updated July 19, 2018 in CentOS, Debian / Ubuntu, Linux KVM, RedHat and Friends, Suse

How do I list a KVM vm guest using virsh command on a Linux based hypervisor?

How to find ip address of Linux KVM guest virtual machine

last updated May 2, 2018 in CentOS, Debian / Ubuntu, Linux, Linux KVM, RedHat and Friends, Suse

How do I find out an IP address of Linux KVM guest from Linux host itself? I wanted to ssh into KVM guest VM. How can I find the IP address of a KVM Virtual Machine Guest on a CentOS Linux 7.x server?

How to reset forgotten root password for Linux KVM qcow2 image/vm

last updated February 10, 2018 in Debian / Ubuntu, Linux, Linux KVM, Troubleshooting

I have Debian Linux VM running on KVM. I think I forgotten the password for the root account and I am no longer able to run ‘su -‘ command. How do I reset the password for the root account for KVM VM which is in qcow2 format?
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