Month: November 2016

As part of my KVM/QEMU setup I needed to be able to copy media from a Windows PC to a Linux Ubuntu Server, for ease I wanted to do this via SMB/ CIFS – I was also using NFS for linux <> linux file sharing, so opted to use the same bind mount point for both NFS and SMBD.

Relevant /etc/fstab entries as below:

# Physical drive mount point
/dev/sdb1 /mnt/media1 ext4 defaults 0 2

# Media1; NFS/ SMBD mountpoint
/mnt/media1 /export/media1 none bind 0 0

Install smbd on Ubuntu server:

apt-get install samba
cp /etc/samba/smb.conf ~
vi /etc/samba/smb.conf

Create a samba login for your user account – in my case, my linux user account was “chris” – you will use this to access the share form your windows client (expect a prompt for username/ password when you browse to the share):

sudo smbpasswd -a chris

Configure smbd – modify paths/ username accordingly:

vi /etc/samba/smbd.conf
# add this to the bottom of the file

[Media]
comment = My Share
path = /export/media1
browsable = yes
valid users = chris
read only = no
create mask = 0755

Finally, start SMBD and set to start automatically on boot – once started, you should be able to browse to “\\<IP/DNS Name of Ubuntu Server>”

# start smbd
service smbd restart

# enable smbd on boot
systemctl enable smbd

I recently bought and setup a Asrock DeskMini with a i5 6400 (will take any desktop S1151 65W CPU), 16GB RAM and an SSDs to act as a KVM/ QEMU host at home. At some point I’ll share the end-to-end setup, but for now suffice to say I am really happy with this very flexible and tiny box of computing power!

I did however want to share some useful VM setup and management commands I have been using, some useful background information:

• Host O/S Ubuntu Server 16.10 – with “Virtual Machine host” option select at install time.
• Network configuration as below

apt-get install -y bridge-utils

cat /etc/network/interfaces

 # The loopback network interface
 auto lo
 iface lo inet loopback

 # The primary network interface
 auto br0
 iface br0 inet static
             address 192.168.1.240
             netmask 255.255.255.0
             broadcast 192.168.1.255
             gateway 192.168.1.1
             dns-nameserver 192.168.1.1
             bridge_ports enp0s31f6
             bridge_stp off
             bridge_fd 0

• Storage layout as below:

 sdb
 ├─sdb4 /var/kvm/images
 ├─sdb2 [SWAP]
 ├─sdb3 part /
 └─sdb1 part /boot/efi

Install virtinst:

apt-get install virtinst

Create directories to store vhd files and iso files used for installing VMs

mkdir -p /var/kvm/images/vm
mkdir -p /var/kvm/images/iso

 

Creating New Virtual Machines

Ubuntu Server 16.04 LTS (from an ISO)

First download Ubuntu server 16.04 LTS ISO:

cd /var/kvm/images/iso
wget http://releases.ubuntu.com/16.04.1/ubuntu-16.04.1-server-amd64.iso

Create the virtual machine – requires the use of sudo – this machine will have 4 vCPUs, 4GB RAM and a 32GB vhd.

virt-install \
 --virt-type=kvm \
 --hvm \
 --name vlinux1 \
 --ram 4096 \
 --disk path=/var/kvm/images/vm/vlinux1.qcow2,size=32,bus=virtio,format=qcow2 \
 --vcpus=4 \
 --os-type linux \
 --os-variant ubuntu16.04 \
 --network bridge=br0 \
 --graphics vnc,listen=0.0.0.0 \
 --noautoconsole \
 --console pty,target_type=serial \
 --cdrom /var/kvm/images/iso/ubuntu-16.04.1-server-amd64.iso

Complete the installation using TightVNC (or another VNC client) to connect via <kvmhostip>:59000

Once completed, the virtual machine will shutdown. Once shutdown the VNC graphics will no longer function, even when you restart the mahcine.

You can configure persistent VNC-based graphics by modifying the XML file associated with the virtual machine – stored under /etc/libvirt/qemu/

vi /etc/libvirt/qemu/vlinux1.xml

# Now remove all lines relating to <graphics> and replace with single line as below:

<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'/>

When you start the machine, you’ll be able to reconnect via VNC. The port number automatically increments for every VM configured like this – based on the order in which the machines start up/ are started up.

 

Managing Virtual Machines

Use virsh to manage and configure VMs – examples below – all require the use of sudo.

# List powered-on / running virtual machines
virsh list --all

# Start / power-on virtual machine "vlinux1"
virsh start vlinux1

# Reset virtual machine "vlinux1"
 virsh reset vlinux1

# Hard power-off virtual machine "vlinux1"
virsh destory vlinux1

# Shutdown virtual machine "vlinux1"
 virsh shutdown vlinux1

# Remove from inventory virtual machine "vlinux1"
 virsh undefine vlinux1

# Set power-on at host start-up for virtual machine "vlinux1"
 virsh autostart vlinux1

# Display VM information for virtual machine "vlinux1"
virsh dominfo vlinux1