grep -E --color=always 'vmx|svm| lm ' /proc/cpuinfo | uniq
Ubuntu
apt install qemu-kvm bridge-utils apt install virtinst libosinfo-bin libguestfs-tools
Debian
apt-get install qemu-system libvirt-clients libvirt-daemon-system apt-get install --no-install-recommends qemu-system libvirt-clients libvirt-daemon-system
make virsh commands available to some non-root user
usermod -aG libvirt USER
check for hardware accel and other things
lsmod | grep kvm #rmmod kvm #modprobe -a kvm kvm-ok virt-host-validate #ls -lF /sys/hypervisor/ #cat /sys/hypervisor/properties/capabilities cat /sys/module/kvm_amd/parameters/nested #cat /sys/module/kvm_amd/parameters/amd_iommu ls -lF /var/run/libvirt/libvirt-sock # root:libvirt ls -lF /dev/kvm # root:kvm systemctl status libvirtd systemctl status libvirt-guests ps auxww | grep libvirtd$ virsh list --all virsh nodeinfo osinfo-query os libguestfs-test-tool
to enable nested virtualization e.g. to setup XEN dom0 within KVM
vi /etc/modprobe.d/kvm.conf
options kvm_amd nested=1
# doesn't show up
#options kvm_amd amd_iommu=pt
rmmod kvm_amd
modprobe kvm_amd
modinfo kvm_amd | grep nested
assuming /data/ is an NFS mount point already, enable it as KVM storage
virsh pool-list
virsh pool-dumpxml default > pool.xml
virsh pool-destroy default
vi pool.xml
<path>/data/kvm</path>
mkdir /data/kvm
virsh pool-create pool.xml
virsh pool-list
brctl show virbr0
on ubuntu, this gets enabled by default
virsh net-list --all
on debian, you need to proceed manually
virsh net-start default virsh net-autostart default
the other way around is to NAT with NETFILTER
virsh net-autostart default --disable virsh net-destroy default
then point the guests against the bridge of your choice
--network bridge=xenbr0,model=virtio \
be ready for virt-install
mkdir -p /data/guests/ ifconfig xenbr0 ifconfig virbr0 osinfo-query os | less
and install some guests
to be able to talk to the other hypervisors and enable the farm, you will have to share a few SSH keys.
to migrate a guest, make sure the machine type is compatible on both ends,
kvm -M ?
and fix it (DO NOT USE the pc alias that is pointing to different latest versions depending on the hypervisors – choose the latest available on all hypervisors e.g. pc-i440fx-2.5) if required,
virsh shutdown GUESTNAME
virsh edit GUESTNAME
<os>
<type arch='x86_64' machine='pc-i440fx-2.5'>hvm</type>
<boot dev='hd'/>
</os>
the available virtual network devices can be displayed as such,
qemu-system-x86_64 -net nic,model=? /dev/null
e.g.,
qemu: Supported NIC models: ne2k_pci,i82551,i82557b,i82559er,rtl8139,e1000,pcnet,virtio
replacing rtl8139 with virtio,
<interface type='bridge'>
<mac address='xx:xx:xx:xx:xx:xx'/>
<source bridge='xenbr0'/>
<model type='virtio'/>
<driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rx_queue_size='256' tx_queue_size='256'>
<host csum='off' gso='off' tso4='off' tso6='off' ecn='off' ufo='off' mrg_rxbuf='off'/>
<guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/>
</driver>
</interface>
you may also have to disable caching on the virtual drive,
<driver name='qemu' type='qcow2' cache='none'/>
refs https://access.redhat.com/solutions/158363
you will then be able to live-migrate,
virsh -c qemu+ssh://ANOTHER-KVM-SRV/system list virsh migrate GUESTNAME qemu+ssh://ANOTHER-KVM-SRV/system
prepare a new bridge config for libvirt and get rid of the crapy defaults,
virsh net-dumpxml default > net-dumpxml.xml virsh net-destroy default #virsh net-undefine default service libvirtd restart cp net-dumpxml.xml br0.xml vi br0.xml <network> <name>br0</name> <uuid>SOME-UUID-HERE</uuid> <bridge name='br0' stp='off' delay='0'/> </network> virsh net-create br0.xml
https://help.ubuntu.com/community/KVM/Networking
https://wiki.libvirt.org/page/VirtualNetworking
https://www.cyberciti.biz/faq/linux-kvm-disable-virbr0-nat-interface/
https://help.ubuntu.com/lts/serverguide/libvirt.html
https://help.ubuntu.com/community/KVM/Installation
https://wiki.xen.org/wiki/Libvirt
https://www.cyberciti.biz/faq/installing-kvm-on-ubuntu-16-04-lts-server/
https://wiki.debian.org/libvirt
https://computingforgeeks.com/virsh-commands-cheatsheet/
Tuning KVM https://www.linux-kvm.org/page/Tuning_KVM
Tuning Kernel https://www.linux-kvm.org/page/Tuning_Kernel
Memory https://www.linux-kvm.org/page/Memory
Chapter 6. Overcommitting with KVM https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/virtualization_administration_guide/chap-virtualization-tips_and_tricks-overcommitting_with_kvm
Chapter 7. KSM https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/virtualization_administration_guide/chap-KSM
How to use the Kernel Samepage Merging feature https://www.kernel.org/doc/Documentation/vm/ksm.txt
KVM host won’t use memory for caching https://serverfault.com/questions/710172/kvm-host-wont-use-memory-for-caching
Virtualization (KVM) and excessive cached RAM https://unix.stackexchange.com/questions/241142/virtualization-kvm-and-excessive-cached-ram
Kernel same-page merging https://en.wikipedia.org/wiki/Kernel_same-page_merging
https://wiki.debian.org/LXC/LibVirtDefaultNetwork
https://wiki.debian.org/KVM#Libvirt_default_network
https://unix.stackexchange.com/questions/340521/create-virbr0-for-virsh
https://linuxconfig.org/how-to-use-bridged-networking-with-libvirt-and-kvm
https://mike42.me/blog/libvirt-migrate-a-vm-from-qemusession-to-qemusystem https://wiki.libvirt.org/page/Failed_to_connect_to_the_hypervisor http://blog.programster.org/kvm-offline-migration https://libvirt.org/migration.html https://libvirt.org/formatdomain.html https://libvirt.org/formatdomain.html#elementsNICS https://wiki.ubuntu.com/QemuKVMMigration https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1617214 https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1637438 https://www.linux-kvm.org/page/Management_Tools https://www.linux-kvm.org/page/Networking https://www.redhat.com/archives/libvirt-users/2015-February/msg00024.html https://access.redhat.com/errata/RHSA-2016:2577
http://ask.xmodulo.com/change-default-location-libvirt-vm-images.html
https://storpool.com/blog/nested-virtualization-with-kvm-and-opennebula
https://wiki.gentoo.org/wiki/QEMU/Linux_guest
https://www.linux-kvm.org/page/Boot_from_virtio_block_device
https://wiki.archlinux.org/title/KVM