LSA2 - 01 Virtualization with KVM
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Virtualization allows hardware to be virtualized so that multiple operating systems can run on a single physical machine. It works by inserting a virtualization layer that provides a virtual operating system for each guest operating system. This document discusses full virtualization, para virtualization, and partial virtualization approaches. It also covers configuring KVM and libvirt for Linux virtualization and managing VMs, networks, storage, and migration.
![Storage pools
●
Create a pool
# virsh pool-create pool.xml
# virsh pool-create-as --name pesho
--type [dir,disk,fs,logical,netfs...]
--target (depending on the type)
●
Refresh the files/volume in a pool
# virsh pool-refresh pool_name](https://image.slidesharecdn.com/01-kvm-140303213700-phpapp01/85/LSA2-01-Virtualization-with-KVM-16-320.jpg)
![Volumes
●
Create
# virsh vol-create volume.xml
# virsh vol-create-as --pool=pool_name
--name pesho_be
--capacity (int in Bytes)
--format [raw,bochs,qcow,qcow2,qed,vmdk]
●
Clone
# virsh vol-clone vol_name new_name --pool pool_name
●
Delete
# virsh vol-delete vol_name --pool pool_name](https://image.slidesharecdn.com/01-kvm-140303213700-phpapp01/85/LSA2-01-Virtualization-with-KVM-17-320.jpg)
![Console &
Debugging
●
Console
–
–
virsh console vm_name
/usr/bin/virsh -c
'qemu+ssh://root@IP:22/system' console vm_name
–
●
Install virt-manager and setup connection to the host node,
then connect to the vm with double click :)
Debugging
# qemu -gdb tcp:127.0.0.1:1212 [...]
# gdb vmlinux-of-guest
(gdb) target remote tcp:127.0.0.1:1212](https://image.slidesharecdn.com/01-kvm-140303213700-phpapp01/85/LSA2-01-Virtualization-with-KVM-23-320.jpg)
LSA2 - 01 Virtualization with KVM
- 3. What is virtualization? ● ● ● mov Full virtualization cmp jmp Para virtualization call push Partial virtualization pop int RAM nop MMU CPU
- 4. What is virtualization? ● ● ● mov Full virtualization cmp jmp Para virtualization call push Partial virtualization pop int RAM nop MMU CPU
- 5. Find out if your CPU is virtualization enabled For Intel VT-x $ grep –color vmx /proc/cpuinfo For AMD V $ grep –color svm /proc/cpuinfo flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer xsave avx lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid
- 6. Organization Host kernel ● KVM ● ● Kernel Kernel VM VM Kernel Kernel VM VM Kernel Kernel VM VM KVM - in the kernel QEMU - System virtualization Libvirt - management simplification
- 7. KVM Kernel configuration CONFIG_KVM_GUEST=y CONFIG_PARAVIRT=y # CONFIG_KVM_DEBUG_FS is not set # CONFIG_PARAVIRT_DEBUG is not set CONFIG_HAVE_KVM=y CONFIG_HAVE_KVM_IRQCHIP=y CONFIG_PARAVIRT_SPINLOCKS=y CONFIG_PARAVIRT_TIME_ACCOUNTING=y CONFIG_PARAVIRT_CLOCK=y CONFIG_HAVE_KVM_IRQ_ROUTING=y CONFIG_VIRT_TO_BUS=y CONFIG_HAVE_KVM_EVENTFD=y CONFIG_VIRTIO_BLK=m CONFIG_KVM_APIC_ARCHITECTURE=y CONFIG_SCSI_VIRTIO=m CONFIG_KVM_MMIO=y CONFIG_VIRTIO_NET=m CONFIG_KVM_ASYNC_PF=y CONFIG_HAVE_KVM_MSI=y CONFIG_VIRTIO_CONSOLE=y CONFIG_HW_RANDOM_VIRTIO=m CONFIG_VIRT_DRIVERS=y CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT CONFIG_VIRTIO=y =y # Virtio drivers CONFIG_KVM=y CONFIG_VIRTIO_PCI=y CONFIG_KVM_INTEL=y CONFIG_VIRTIO_BALLOON=m # CONFIG_KVM_AMD is not set CONFIG_VIRTIO_MMIO=m # CONFIG_KVM_MMU_AUDIT is not set CONFIG_KVM_DEVICE_ASSIGNMENT=y CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES=y # CONFIG_DEBUG_VIRTUAL is not set CONFIG_VIRTUALIZATION=y
- 8. KVM Kernel configuration Processor type and features -> Linux guest support -> * BUS options -> PCI IOV Device Drivers -> Block devices -> Virtio block driver SCSI device support -> SCSI low-level drivers -> virtio-scsi Network device support -> Virtio network driver Character devices -> * HW Random Number Generator Virtio console Virtio drivers -> * Virtualization -> *
- 9. Create ● Start ● Talk to QEMU ●
- 11. KVM information ● List VMs – – ● virsh list virsh list – all (including the suspended and stopped) Node Information – virsh nodeinfo – information about the host node – virsh dominfo vm_name - information about the VM – virsh vcpuinfo vm_name - CPU info about the VM
- 12. ● Start – ● VM Management :) virsh start vm_name Stop – - soft shutdown – ● virsh shutdown vm_name virsh destroy vm_name - power down Restart – – virsh shutdown vm_name – virsh destroy vm_name – ● virsh reboot vm_name virsh start vm_name - power cycle Suspend – virsh suspend vm_name - to RAM
- 13. Hibernate ● Save - save the VM state to a file – – ● virsh save vm_name virsh save-image-define save-file.img Restore – ● virsh restore save-file.img File location – /var/lib/libvirt/qemu/
- 14. Network ● List all defined networks – ● Get information for predefined network – ● virsh net-info net_name Activate a network on Host boot – ● virsh net-list virsh net-autostart net_name Start/Stop/Remove network – virsh net-start net_name – virsh net-destroy net_name – virsh net-undefine net_name
- 15. Storage pools ● List all defined storage pools – ● Get information for predefined pool – ● virsh pool-info pool_name Activate a storage pool on Host boot – ● virsh pool-list virsh pool-autostart pool_name Start/Stop/Remove network – virsh pool-start net_name – virsh pool-destroy net_name – virsh pool-undefine net_name
- 16. Storage pools ● Create a pool # virsh pool-create pool.xml # virsh pool-create-as --name pesho --type [dir,disk,fs,logical,netfs...] --target (depending on the type) ● Refresh the files/volume in a pool # virsh pool-refresh pool_name
- 17. Volumes ● Create # virsh vol-create volume.xml # virsh vol-create-as --pool=pool_name --name pesho_be --capacity (int in Bytes) --format [raw,bochs,qcow,qcow2,qed,vmdk] ● Clone # virsh vol-clone vol_name new_name --pool pool_name ● Delete # virsh vol-delete vol_name --pool pool_name
- 18. Snapshots # virsh snapshot-create-as vm_name snapshot1 "backup1" --disk-only --atomic # virsh snapshot-list vm_name # virsh snapshot-info vm_name --snapshotname snapshot1
- 19. Migration ● Migration with shared storage virsh migrate --live Jab2 qemu+ssh://192.168.0.5/system ● Migration with local storage # qemu-img info /vm/vm-test.img image: /vm/jivko-test.img file format: raw virtual size: 8.0G (8589934592 bytes) disk size: 8.0G # qemu-img create -f raw /vm/vm-test.img 8G Formatting '/vm/jivko-test.img', fmt=raw size=8589934592 # virsh migrate --persistent --live --copy-storage-all Jab2 qemu+ssh://192.168.0.5/system
- 20. Create a new VM ● Installation image ● Command – qemu -drive file=ubuntu-lucid.img,if=virtio /path/to/kernel/bzImage -kernel -append "console=ttyS0 root=/dev/vda" -m 512 -smp 1 -fsdev local,id=test_dev,path=shared,security_model=none -enable-kvm
- 21. Backups
- 22. Configuration ● Fuck... it's XML based... /etc/libvirt/qemu/vm_name.xml /etc/libvirt/qemu/autostart /etc/libvirt/qemu/networks /var/lib/libvirt/images
- 23. Console & Debugging ● Console – – virsh console vm_name /usr/bin/virsh -c 'qemu+ssh://root@IP:22/system' console vm_name – ● Install virt-manager and setup connection to the host node, then connect to the vm with double click :) Debugging # qemu -gdb tcp:127.0.0.1:1212 [...] # gdb vmlinux-of-guest (gdb) target remote tcp:127.0.0.1:1212
- 24. Common issues ● Sometimes libvirt can't start some VMs – check if they have .save files in ● – check if there are files with the VM name in ● – /var/lib/libvirt/qemu/images /var/lib/libvirt/qemu/save If there are any files for that VM in either of these dirs, remove them and the VM should start