Re: External snapshots and using qemu without libvirt

[Simon Becherer]

Am 13.09.21 um 16:34 schrieb Leek, Jim:
> I'm still messing about with qemu snapshots.  I have internal snapshots 
> working OK.  But I read this in the RHEL documentation: "Important: Red Hat 
> recommends the use of external snapshots." Then on a later page I found this: 
> "However, external snapshots are currently not fully implemented on Red Hat 
> Enterprise Linux 7, and are not available when using virt-manager."    Ha!
> 
> Maybe external snapshots will work if I run qemu without libvirt? But I'm 
> having trouble getting that to work as well.  I found this page and followed 
> the instructions: 
> https://developers.redhat.com/blog/2020/03/06/configure-and-run-a-qemu-based-vm-outside-of-libvirt
>  (although he talks about qemu-system-x86_64 and I'm using qemu-kvm, but I 
> hope that doesn't make any difference.)
> 
> But I can't get it to work.  I've tried a number of modifications, and the 
> command line below launches the VM, but I can't access it.  No screen pops 
> up, and I can't get there via ssh.  If I take off the last lines about the 
> display it will say I can use VNC ::1:5900, but when I connect there it with 
> a VNC client it just says "guest has not initialized display yet."
> 
> Anybody have any ideas on any of this?
> Thanks
> 
> Here's the command line I've tried.  The removing the last 2 arguments does 
> change the display behavior, but not to any particular benefit:
> #! /bin/sh 
> export LC_ALL=C 
> export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin 
> export HOME=/var/lib/libvirt/qemu/domain-6-centos8_3 
> export XDG_DATA_HOME=/var/lib/libvirt/qemu/domain-6-centos8_3/.local/share 
> export XDG_CACHE_HOME=/var/lib/libvirt/qemu/domain-6-centos8_3/.cache 
> export XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain-6-centos8_3/.config 
> export QEMU_AUDIO_DRV=spice 
> /usr/libexec/qemu-kvm \
> -name guest=centos8_3,debug-threads=on \
> -S \
> -enable-fips \
> -machine pc-q35-rhel8.2.0,accel=kvm,usb=off,vmport=off,dump-guest-core=off \
> -cpu 
> Skylake-Server-IBRS,ss=on,vmx=on,pdcm=on,hypervisor=on,tsc-adjust=on,clflushopt=on,umip=on,pku=on,md-clear=on,stibp=on,arch-capabilities=on,ssbd=on,xsaves=on,ibpb=on,ibrs=on,amd-stibp=on,amd-ssbd=on,skip-l1dfl-vmentry=on,pschange-mc-no=on
>  \
> -m 24000 \
> -overcommit mem-lock=off \
> -smp 2,sockets=2,cores=1,threads=1 \
> -uuid 8dd20f24-3e31-464c-956e-67d3d9f2a83c \
> -no-user-config \
> -rtc base=utc,driftfix=slew \
> -global kvm-pit.lost_tick_policy=delay \
> -no-hpet \
> -no-shutdown \
> -global ICH9-LPC.disable_s3=1 \
> -global ICH9-LPC.disable_s4=1 \
> -boot strict=on \
> -device 
> pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2
>  \
> -device pcie-root-port,port=0x11,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 \
> -device pcie-root-port,port=0x12,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x2 \
> -device pcie-root-port,port=0x13,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x3 \
> -device pcie-root-port,port=0x14,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x4 \
> -device pcie-root-port,port=0x15,chassis=6,id=pci.6,bus=pcie.0,addr=0x2.0x5 \
> -device pcie-root-port,port=0x16,chassis=7,id=pci.7,bus=pcie.0,addr=0x2.0x6 \
> -device pcie-root-port,port=0x17,chassis=8,id=pci.8,bus=pcie.0,addr=0x2.0x7 \
> -device pcie-pci-bridge,id=pci.9,bus=pci.1,addr=0x0 \
> -device qemu-xhci,p2=15,p3=15,id=usb,bus=pci.2,addr=0x0 \
> -device virtio-serial-pci,id=virtio-serial0,bus=pci.3,addr=0x0 \
> -blockdev 
> '{"driver":"file","filename":"/home/leek2/qemu/rhel8_1-clone-1.qcow2","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}'
>  \
> -blockdev 
> '{"node-name":"libvirt-1-format","read-only":false,"driver":"qcow2","file":"libvirt-1-storage","backing":null}'
>  \
> -device 
> virtio-blk-pci,scsi=off,bus=pci.4,addr=0x0,drive=libvirt-1-format,id=virtio-disk0,bootindex=1
>  \
> -device 
> virtio-net-pci,netdev=hostnet0,id=net0,mac=6c:2b:59:e9:44:49,bus=pci.7,addr=0x0
>  \
> -netdev bridge,id=hostnet0,br=virbr0 \
> -chardev spicevmc,id=charchannel0,name=vdagent \
> -device 
> virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
>  \
> -device virtio-balloon-pci,id=balloon0,bus=pci.5,addr=0x0 \
> -object rng-random,id=objrng0,filename=/dev/urandom \
> -device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.6,addr=0x0 \
> -msg timestamp=on \
> -device 
> qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pcie.0,addr=0x1
>  \
> -spice 
> port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on
> 


Without checking all of your config:
> -spice 
> port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on
should be: disable-ticketing=on

i would suggest you fire up your quemu with libvirt and then check the 
generated startline
with
ps fax |grep qemu

regards,

simoN

-- 
www.becherer.de

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