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Table of Contents
KVM hypervisor host
Instructions to setup the host system (the iron, of the frame).
Distribution: Debian 6 (Squeeze) or 7 (Wheezy) or 8 (jessie)
preparation
Install a minimal debian system with a static IP-number.
Configure locale (for perl and apt-get tooling):
export LANGUAGE=en_US.UTF-8 export LANG=en_US.UTF-8 export LC_ALL=en_US.UTF-8 locale-gen en_US.UTF-8 dpkg-reconfigure locales
Install the software:
apt-get install qemu-kvm libvirt-bin virtinst virt-top
For multiple networking cards:
apt-get install bridge-utils vlan
Install usefull tooling:
apt-get install htop iftop iotop dnsutils tcpdump kpartx mc xfsprogs
config
Add to /etc/network/interfaces
auto br0
iface br0 inet static
bridge_ports eth0
bridge_stp off
bridge_maxwait 0
address 10.11.12.10
netmask 255.255.255.0
broadcast 10.11.12.255
gateway 10.11.12.1
dns-nameservers 10.11.12.66 10.110.12.66
dns-search intra.example.com
auto br1
iface br1 inet manual
bridge_ports eth1
bridge_stp off
bridge_maxwait 0
auto br2
iface br2 inet manual
bridge_ports eth2
bridge_stp off
bridge_maxwait 1
## dot1q Trunk
iface eth3.11 inet manual
vlan-raw-device eth3
iface eth3.12 inet manual
vlan-raw-device eth3
auto br3-vlan11
iface br3-vlan11 inet manual
bridge_ports eth3.11
bridge_stp off
bridge_maxwait 0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
up /sbin/ifconfig $IFACE up || /bin/true
automatic suspend/resume
Debian 7
Enable automatic save2disk at shutdown + resume at startup in /etc/default/libvirt-guests by setting:
ON_BOOT=start ON_SHUTDOWN=suspend
Debian 6
Configure automatic suspend/resume for the guests:
cd /etc/init.d cp /usr/share/doc/libvirt-bin/examples/libvirt-suspendonreboot virsh-suspend update-rc.d libvirt-suspendonreboot defaults 29 71 mkdir /var/lib/libvirt/autosuspend
real text-mode console
Debian 7 (Grub 2)
/etc/default/grub
GRUB_DEFAULT=0 GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="" GRUB_CMDLINE_LINUX="nomodeset" GRUB_TERMINAL=console GRUB_GFXMODE=800x600 GRUB_GFXPAYLOAD_LINUX=keep GRUB_INIT_TUNE="480 440 1"
Power
For APC equipment, there is software ready in the Debian repository. Good reason to buy this if you need uninterrupted power. After connecting the equipment (power and USB-cabling), install the ups-daemon software:
apt-get install apcupsd apcupsd-doc apcupsd-cgi
Edit the configfile /etc/apcupsd/apcupsd.conf
## apcupsd.conf v1.1 ## # for apcupsd release 3.14.12 (29 March 2014) - debian UPSNAME apcups01 UPSCABLE usb UPSTYPE usb DEVICE LOCKFILE /var/lock SCRIPTDIR /etc/apcupsd PWRFAILDIR /etc/apcupsd NOLOGINDIR /etc ONBATTERYDELAY 6 BATTERYLEVEL 90 MINUTES 10 TIMEOUT 0 ANNOY 300 ANNOYDELAY 60 NOLOGON disable KILLDELAY 0 NETSERVER off NISIP 127.0.0.1 NISPORT 3551 EVENTSFILE /var/log/apcupsd.events EVENTSFILEMAX 10 UPSCLASS standalone UPSMODE disable STATTIME 0 STATFILE /var/log/apcupsd.status LOGSTATS off DATATIME 0
And flag the parameter ISCONFIGURED in /etc/default/apcupsd to yes.
docs
Distribution: Ubuntu 12.04 / 14.04 LTS
Use the Debian 6 howto.
Below some specific Ubuntu actions.
real text-mode console
/etc/default/grub
GRUB_DEFAULT=0 #GRUB_HIDDEN_TIMEOUT=0 #GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` #GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" #GRUB_CMDLINE_LINUX_DEFAULT="text" #GRUB_CMDLINE_LINUX="" #GRUB_CMDLINE_LINUX="init=/sbin/init -v noplymouth INIT_VERBOSE=yes" #GRUB_CMDLINE_LINUX="vga=769" GRUB_CMDLINE_LINUX="nomodeset" GRUB_TERMINAL=console #GRUB_GFXMODE=640x480
locales
locale-gen nl_NL.UTF-8 dpkg-reconfigure locales
Distribution: CentOS 6.0
preparation
Install a minimal CentOS 6.0 system with a static IP-number.
Install the software:
yum install kvm virt-manager libvirt
Nested KVM
(this feature is only for the purpose of testing, not for production)
Check the CPU-architecture of the physical system with:
lscpu
Create or edit /etc/modprobe.d/kvm.conf (or /etc/modprobe.d/qemu-system-x86.conf on ubuntu) on the host/hypervisor system and add:
options kvm_intel nested=1 #options kvm_amd nested=1
Reboot the system to effect the setting.
Create a VM, and use “copy host CPU configuration” in the cpu-section of the VM-definition.
In the VM you can check the kvm nesting with:
cat /sys/module/kvm_intel/parameters/nested
Also:
egrep '(vmx|svm)' /proc/cpuinfo
will give one or more lines.
KVM guest actions
Usefull tooling for a VM
ACPI-stuff
Requirements Debian:
apt-get install acpid
disk-changes changes
Requirements Debian:
apt-get install parted
Probe the changed partition-table:
partprobe
enlarge a vdisk
First enlarge the vdisk in the KVM host (with lvm or whatever).
In case the (v)disk is larger dan 2TB, use parted instead of fdisk. Below an example of a 3 TB disk, which is enlarged to 3.5TB. The KVM guest is rebooted, and the filesystem on it is umounted. The trick is to delete te partition (rm) and to recreate it directly afterwards, with the same startingpoint, and with a lager number as the endpoint.
parted -l /dev/vdc
# parted /dev/vdc (parted) p Model: Virtio Block Device (virtblk) Disk /dev/vdc: 3848GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 3299GB 3299GB xfs
# parted /dev/vdc (parted) rm 1
# parted /dev/vdc (parted) mkpart Partition name? []? File system type? [ext2]? xfs Start? 1049kB End? 3848GB
Instead of a number as an answer to the question “End”, it is also possible to use -1. This will use the largest possible value, ie. the end of the disk.
The action above can also be done in a one-liner:
# parted /dev/vdc (parted) mkpart primary xfs 1049kB -1
View the result:
# parted /dev/vdc (parted) p Model: Virtio Block Device (virtblk) Disk /dev/vdc: 3848GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 3848GB 3848GB xfs (parted) q
The partitioning part is done now.
Resize the filesystem on the partition. For example with resizefs or xfs_growfs.
KVM administration workstation
Ubuntu/Debian
For a Ubuntu/Debian based workstation with graphical display:
apt-get install ssh virt-manager
Only when it is needed to run kvm-vpsses on the workstation also, install also the package kvm.
Start virtmanager, and click on 'add-connection'.
MS-windows
Using Virt-manager via XMing and putty:
http://blog.allanglesit.com/2011/03/linux-kvm-managing-kvm-guests-using-virt-manager-on-windows/
KVM administration
Instructions how to administer the KVM host system (the iron, of the frame).
disk administration of the VPSses
creation of diskspace for a VPS
A wide range of storage formats are available to choose from. A few thoughts:
- for the best performance, use a raw partition as storage backend for a VPS. You can create a partition on the host or a logical-volume on the host. This will be assigned to the guest.
- if you are using raw volumes or partitions, it is best to set the caching option to 'none' (to avoid the cache completely, which reduces data copies and bus traffic).
- if you are using files, and you are not in the need of storage guarantees, for example for testing purposes, you can choose 'writeback caching' which offers maximum speed.
- if your guest supports it, use the 'virtio' interface.
- don't the linux filesystem btrfs on the host for image files. It will result in low I/O performance.
enlarge diskspace inside a VPS
To enlarge a disk of a VPS , use the following procedure:
On the VM-host:
In case of raw-devices, enlarge the logical-volume:
lvresize -L +2G /dev/vg01/VPSfoo01
to grow the disk/LUN of VPSfoo with 2G
In case of file-devices:
cd /var/lib/libvirt/images dd if=/dev/null of=VPSfoo.img bs=1 count=0 seek=10G
to grow the disk/LUN of VPSfoo to 10G
After this, stop and start the VPS. This is needed, because the new disk-geometry has to be read by the kernel.
In the VPS:
Now start fdisk, and it will detect a larger disk. Add a partition, or repartition the partition at the end of the disk (you did have this procedure in mind, when designing the disk-layout, didn't you 
Now run pvresize on this partition, and after this, the volume-group has free-extents. Use these to grow one or more logical-volumes.
add a lun to a VPS
To attach a storage lun to a running VPS , use the following procedure:
On the VM-host:
Create a new raw-device (and optionally make a symlink).
Attach the raw-device to the vps (in this case, the name is vpsfoo2 and it is the second virtio-disk aka vdb):
virsh attach-disk vpsfoo2 /var/lib/libvirt/images/vpsfoo2data.img vdb --targetbus virtio --live
