Virtualization Questions

Which command is used in KVM for VMs live migration?

'virsh migrate --live machine__name qemu +ssh://destination__sever/system'

How to connect to a particular VM using virt-viewer?

'virt viewer -c qemu:///system <VM__name>

What is Dom0 to Xen?

Dom0 or Domain0 is the initial domain started by the Xen hypervisor. It has special rights to access the domain and access the hardware directly. Dom0 is responsible for running all of the device drivers on the hardware.

What are the differences between Xen and KVM?

For Xen hypervisor first we have to install Xen kernel and have to boot the machine with Xen kernel where is as KVM is kernal based Virtualization, we don't need any extra kernel for KVM. Xen by default doesn't support full virtualization whereas KVM does.

What is the difference between full virtualization and para virtualization?

Full virtualization and para virtualization both come in the form of hardware virtualization.

What is a hypervisor?

Hypervisor is a piece of software being installed on the physical machine, which then further runs and creates the virtual machine. Virtual machines are known as guest machines and the host machine is the hypervisor on which guest machines are created.

Para Virtualization

It is a virtualization in which the guest machine is aware of that it is in a virtualized environment. If guest machine requires resource like cpu & memory it issues commands to the virtual operating system instead of directly communicating with actual hardware.

Full Virtualization

It is virtualization where guest machines(virtual machines) are unaware they are virtual environments therefore hardware is virtualized by the host operating system so the host can issue commands to what it thinks is actual hardware but is just simulated hardware from the host.

What are the basic requirements of VM live migration in KVM?

Some of the basic requirements are listed below. 1. The guest image or virtual machine image must be located on a shared storage and it must be accessible using iSCSI, NFS, GFS2 or Fibre Channel. 2. The shared storage must be mounted on the same path as both hypervisors and host. 3. Both hypervisors and host must run on the same version of KVM. 4. Both guest or VMs must have the same network configuration and bridging configuration (their ips must be different)

How to identify the KVM version?

To find the KVM version use the command virsh version.

What are Type-1 and Type-2 hypervisors?

Type-1 hypervisor runs on the bare metal of hardware. Hyper-V and ESXI server are examples of Type-1 hypervisor. Type-2 hypervisor is hosted by the operating system e.g., Microsoft Virtual Server and VMware server.

How to get the hardware information of KVM guest machine.

Use the command 'virsh dominfo <domain-name/ VM name>'

How to shutdown, reboot & start VMs (domain-ids) in Xen?

Use xm command: # xm shutdown [domain-id] # xm reboot [domain-id] # xm start [domain-id]

Which command is used to list all virtual machines running on the KVM hypervisor?

Using the command 'virsh list-all' one can list all of the virtual machines running irrespective of state.

What is the use of virsh command?

Virsh is the interface or command for managing the virtual machines based on KVM and Xen hypervisor. On virsh interface virtual machines are identified by their domain name, virsh is generally used to list current domain names, or to create, pause, and shut down domains.

What are the different types of virtualization?

Virtualization can be used in many ways and can take many forms. 1. Server virtualization 2. Network virtualization 3. Hardware 4. Desktop 5. Application 6. User

What is virtualization?

Virtualization is a technique used for creating virtual resources (rather than actual) such as, server, storage device, network and operating system. Virtualization is disassociating the tight bond between software and hardware.

How to force shutdown the KVM virtual machine from the command line?

We can forcefully shutdown the VM using the command 'virsh destroy machine_name'. This command should only be used in a case where VM is in a hung state because force shutdown may harm the system.

What are different hypervisors available in linux?

Xen and KVM are two hypervisors available in Linux.

How to verify Virtualization Technology (VT) is enabled in your server's BIOS or not.

grep -E 'svm|vmx' /proc/cpuinfo (vmx for intel, svm for AMD)

How to get the console or guest of virtual machine in Xen?

xm console <domain-id>