linux:kvm [Starlab knowledge base]

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====== Instalace KVM ======
TODO: udelat tutorial :)
<code bash>aptitude -y install qemu-kvm libvirt-bin virtinst bridge-utils </code>
====== Vytvoreni guesta ======
===== Debian 8 =====
  - Install gues:<code bash>virt-install -n vps1 --ram=2048 --vcpus=2 --location='http://ftp.cz.debian.org/debian/dists/jessie/main/installer-amd64/' --disk path=/dev/shared_vg/vps1  --network bridge=br0 --os-type linux --console pty,target_type=serial --graphics none --os-variant generic --extra-args 'console=ttyS0,115200n8 serial'</code>
  - put following line into grubu in line starting with linux <code>console=tty0 console=ttyS0,115200</code>
  - put "console=tty0 console=ttyS0,115200" into /etc/default/grub in GRUB_CMDLINE_LINUX_DEFAULT <code>GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200"</code>
  - update grub (this one i always forget and wondering why it doesn't work :))<code bash>update-grub</code>

====== Vzdaleny pristup ======
===== Pres certifikaty =====
https://libvirt.org/remote.html
  * note: nepovedlo se mi rozbehat
===== Pres libvirt + ssh =====
<code python>
import libvirt
conn = libvirt.open("qemu+ssh://root@10.0.0.120")

# vypis bezicich vps (interni ID)
conn.listDomainsID()

# nalezeni vps podle ID (pouze bezici)
vps = conn.lookupByID(1)

# nalezeni vps podle jmena (bere i masiny, ktere jsou nebezici, ale nadefinovane)
vps1 = conn.lookupByName("vps1")

# spusteni
vps1.start()

# pause
vps1.suspend()

# unpause
vps1.resume()

# shut down
vps1.shutdown()

# force shutdown
vps1.destroy()

# close connection
conn.close()
</code>
====== HOT migration ======
  * NOTE: we cannot use kvm migration, since we use mirrored clustered LVM (mirrored volume could not be activated on more than one node in time)
  * use following script instead:<code bash>
#!/bin/bash

if [ $# != 2 ]; then
        echo "Usage: move_vps.sh domain destination"
        exit 1
fi

MACHINE=$1
DESTINATION=$2

XML_NAME=/tmp/$MACHINE
virsh dumpxml $MACHINE > $XML_NAME
scp ${XML_NAME} root@${DESTINATION}:${XML_NAME}
rm $XML_NAME

IMG_NAME=/tmp/${MACHINE}.img
virsh save $MACHINE $IMG_NAME
scp $IMG_NAME root@${DESTINATION}:${IMG_NAME}
rm $IMG_NAME

lvchange -an /dev/shared_vg/$MACHINE
ssh root@$DESTINATION "lvchange -ay /dev/shared_vg/$MACHINE"
ssh root@$DESTINATION "virsh define ${XML_NAME}"
ssh root@$DESTINATION "virsh restore $IMG_NAME"
ssh root@$DESTINATION "rm $IMG_NAME"</code>


====== Correct shutdown ======
// Keywords: Libvirt Can't shutdown or reboot virtual guest.\
I can't reboot or shutdown the guest vm from the host mac//

<code bash>
modprobe virtio_console
apt install qemu-guest-agent
service qemu-ga restart
apt install acpid
</code>

Test if the agent is running
<code bash>
    virsh qemu-agent-command jakub-sevcik '{"execute":"guest-info"}'
</code>
linux/kvm.txt · Last modified: 2019/01/11 13:14 by admin