Setup a KVM Hypervisor on Ubuntu to Host Virtual Machines
Today we will setup a KVM (Kernel Virtual Machine) Hypervisor, where we can host Virtual Machines. In order to do so, your host needs to Support Hardware Virtualization.
What we will be doing today:
- Check if your host supports Hardware Virtualization
- Setup the KVM Hypervisor
- Setup a Alpine VM
Check for Hardware Virtualization Support:
We will install the package required to do the check:
$ sudo apt update && sudo apt install cpu-checker -y
Once that is installed, run kvm-ok and if its supported, your output should look something like this:
$ kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used
Installing KVM
Update your System and get the Packages required to Setup KVM:
$ sudo apt update && sudo apt upgrade -y
$ apt install bridge-utils qemu-kvm libvirt-bin virtinst -y
Add your user to the libvirtd group:
$ sudo usermod -G libvirtd $USER
Check that the libvirtd service is running:
$ sudo systemctl is-active libvirtd
active
You will also find that there is a new interface configured called virbr0 in my case.
Provision the Alpine VM and Setup OpenSSH:
Get the ISO:
$ wget http://dl-cdn.alpinelinux.org/alpine/v3.7/releases/x86_64/alpine-virt-3.7.0-x86_64.iso
Provision the VM:
$ virt-install \
--name alpine1 \
--ram 256 \
--disk path=/var/lib/libvirt/images/alpine1.img,size=8 \
--vcpus 1 \
--os-type linux \
--os-variant generic \
--network bridge:virbr0,model=virtio \
--graphics none \
--console pty,target_type=serial \
--cdrom ./alpine-virt-3.7.0-x86_64.iso
After this, you will be dropped into the console:
Starting install...
Allocating 'alpine1.img' | 8 GB 00:00:01
Creating domain... | 0 B 00:00:00
Connected to domain alpine1
Escape character is ^]
ISOLINUX 6.04 6.04-pre1 Copyright (C) 1994-2015 H. Peter Anvin et al
boot:
OpenRC 0.24.1.a941ee4a0b is starting up Linux 4.9.65-1-virthardened (x86_64)
Welcome to Alpine Linux 3.7
Kernel 4.9.65-1-virthardened on an x86_64 (/dev/ttyS0)
localhost login:
Login with the root user and no password, then setup the VM by running setup-alpine:
localhost login: root
Welcome to Alpine!
localhost:~# setup-alpine
After completing the prompts reboot the VM by running reboot, then you will be dropped out of the console. Check the status of the reboot:
$ virsh list
Id Name State
----------------------------------------------------
2 alpine1 running
As we can see our guest is running, lets console to our guest, provide the root user and password that you provided during the setup phase:
$ virsh console 2
Connected to domain alpine1
Escape character is ^]
alpine1 login: root
Password:
Welcome to Alpine!
Setup OpenSSH so that we can SSH to our guest over the network:
$ apk update
$ apk add openssh
Configure SSH to accept Root Passwords, this is not advisable for production environments, but for testing this is okay. For Production servers, we will rather look at Key Based Authentication etc.
$ sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/g' /etc/ssh/sshd_config
$ /etc/init.d/sshd restart
Get the IP Address:
$ ifconfig
eth0 Link encap:Ethernet HWaddr 52:54:00:D0:48:0C
inet addr:192.168.122.176 Bcast:192.168.122.255 Mask:255.255.255.0
inet6 addr: fe80::5054:ff:fed0:480c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:55 errors:0 dropped:28 overruns:0 frame:0
TX packets:34 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4545 (4.4 KiB) TX bytes:3345 (3.2 KiB)
Exit the guest by running exit and Ctrl + ] to exit the console session.
Now SSH to your Alpine VM:
$ ssh root@192.168.122.176
root@192.168.122.176's password:
Welcome to Alpine!
Some Useful Commands:
List Running VMs:
$ virsh list
Id Name State
----------------------------------------------------
3 alpine1 running
Shutdown a VM:
$ virsh shutdown alpine1
Domain alpine1 is being shutdown
List all VMs:
$ virsh list --all
Id Name State
----------------------------------------------------
- alpine1 shut off
Delete a VM:
$ virsh shutdown alpine1 #or to force shutdown:
$ virsh destroy alpine1
$ virsh undefine alpine1
Any future KVM posts will be tagged under KVM and Alpine posts will be available under the Alpine tag.