KVM (Kernel-based Virtual Machine) is an open source full virtualization solution for Linux like systems, KVM provides virtualization functionality using the virtualization extensions like Intel VT or AMD-V. Whenever we install KVM on any linux box then it turns it into the hyervisor by loading the kernel modules like kvm-intel.ko( for intel based machines) and kvm-amd.ko ( for amd based machines).
KVM allows us to install and run multiple virtual machines (Windows & Linux). We can create and manage KVM based virtual machines either via virt-manager graphical user interface or virt-install & virsh cli commands.
In this article we will discuss how to install and configure KVM hypervisor on Ubuntu server.
Login to your server and perform the following steps:-
Step 1:- Pre-installation checklist
Check that your CPU supports hardware virtualization
To run KVM, you need a processor that supports hardware virtualization. Intel and AMD both have developed extensions for their processors, deemed respectively Intel VT-x (code name Vanderpool) and AMD-V (code name Pacifica). To see if your processor supports one of these, you can review the output from this command:
egrep -c '(vmx|svm)' /proc/cpuinfo
If 0 it means that your CPU doesn't support hardware virtualization.
If 1 or more it does - but you still need to make sure that virtualization is enabled in the BIOS.
By default, if you booted into XEN kernel it will not display svm or vmx flag using the grep command. To see if it is enabled or not from xen, enter:
cat /sys/hypervisor/properties/capabilities
You must see hvm flags in the output.
Alternatively, you may execute:
kvm-ok
which may provide an output like this:
INFO: /dev/kvm exists KVM acceleration can be used
If you see :
INFO: Your CPU does not support KVM extensions KVM acceleration can NOT be used
You can still run virtual machines, but it'll be much slower without the KVM extensions.
NOTE: You may see a message like "KVM acceleration can/can NOT be used". This is misleading and only means if KVM is *currently* available (i.e. "turned on"), *not* if it is supported.
Use a 64 bit kernel (if possible)
Running a 64 bit kernel on the host operating system is recommended but not required.
To serve more than 2GB of RAM for your VMs, you must use a 64-bit kernel (see 32bit_and_64bit). On a 32-bit kernel install, you'll be limited to 2GB RAM at maximum for a given VM.
- Also, a 64-bit system can host both 32-bit and 64-bit guests. A 32-bit system can only host 32-bit guests.
To see if your processor is 64-bit, you can run this command:
egrep -c ' lm ' /proc/cpuinfo
If 0 is printed, it means that your CPU is not 64-bit.
If 1 or higher, it is. Note: lm stands for Long Mode which equates to a 64-bit CPU.
Now see if your running kernel is 64-bit, just issue the following command:
uname -m
x86_64 indicates a running 64-bit kernel. If you use see i386, i486, i586 or i686, you're running a 32-bit kernel.
Note: x86_64 is synonymous with amd64.
No comments:
Post a Comment