43-KVM虚拟化-利用libvirt服务进行KVM虚拟机管理

[root@ubuntu2204 ~]#virsh list --all
Id Name State
------------------------------------
2 centos7-mooreyxia running
- rocky8 shut off

[root@ubuntu2204 ~]#systemctl status libvirtd
● libvirtd.service - Virtualization daemon
Loaded: loaded (/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled)
Active: active (running) since Sat 2022-12-31 17:53:28 CST; 17h ago
TriggeredBy: ● libvirtd-ro.socket
● libvirtd.socket
● libvirtd-admin.socket
Docs: man:libvirtd(8)
https://libvirt.org
Main PID: 871 (libvirtd)
Tasks: 23 (limit: 32768)
Memory: 72.6M
CPU: 9.258s
CGroup: /system.slice/libvirtd.service
├─871 /usr/sbin/libvirtd
├─987 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
└─988 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

Dec 31 17:53:30 ubuntu2204.wang.org dnsmasq[987]: using nameserver 127.0.0.53#53
Dec 31 17:53:30 ubuntu2204.wang.org dnsmasq[987]: read /etc/hosts - 7 addresses
Dec 31 17:53:30 ubuntu2204.wang.org dnsmasq[987]: read /var/lib/libvirt/dnsmasq/default.addnhosts - 0 addresses
Dec 31 17:53:30 ubuntu2204.wang.org dnsmasq-dhcp[987]: read /var/lib/libvirt/dnsmasq/default.hostsfile
Jan 01 11:11:55 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPDISCOVER(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:11:55 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPOFFER(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:11:55 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPREQUEST(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:11:55 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPACK(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:18:35 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPREQUEST(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:18:35 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPACK(virbr0) 192.168.122.23 52:54:00:18:b7:d2

#停止libvirtd服务，socket还在运行，systemctl会自动激活socket，所以libvirtd会自动重启
[root@ubuntu2204 ~]#systemctl stop libvirtd
Warning: Stopping libvirtd.service, but it can still be activated by:
libvirtd-ro.socket
libvirtd.socket
libvirtd-admin.socket
[root@ubuntu2204 ~]#systemctl status libvirtd-ro.socket
● libvirtd-ro.socket - Libvirt local read-only socket
Loaded: loaded (/lib/systemd/system/libvirtd-ro.socket; enabled; vendor preset: enabled)
Active: active (listening) since Sat 2022-12-31 17:53:24 CST; 17h ago
Triggers: ● libvirtd.service
Listen: /run/libvirt/libvirt-sock-ro (Stream)
CGroup: /system.slice/libvirtd-ro.socket

Dec 31 17:53:24 ubuntu2204.wang.org systemd[1]: Listening on Libvirt local read-only socket.
[root@ubuntu2204 ~]#systemctl status libvirtd
○ libvirtd.service - Virtualization daemon
Loaded: loaded (/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Sun 2023-01-01 11:27:32 CST; 1min 32s ago
TriggeredBy: ● libvirtd-ro.socket
● libvirtd.socket
● libvirtd-admin.socket
Docs: man:libvirtd(8)
https://libvirt.org
Process: 871 ExecStart=/usr/sbin/libvirtd $LIBVIRTD_ARGS (code=exited, status=0/SUCCESS)
Main PID: 871 (code=exited, status=0/SUCCESS)
Tasks: 2 (limit: 32768)
Memory: 57.1M
CPU: 9.370s
CGroup: /system.slice/libvirtd.service
├─987 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
└─988 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

Jan 01 11:11:55 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPREQUEST(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:11:55 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPACK(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:18:35 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPREQUEST(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:18:35 ubuntu2204.wang.org dnsmasq-dhcp[987]: DHCPACK(virbr0) 192.168.122.23 52:54:00:18:b7:d2
Jan 01 11:27:32 ubuntu2204.wang.org systemd[1]: Stopping Virtualization daemon...
Jan 01 11:27:32 ubuntu2204.wang.org systemd[1]: libvirtd.service: Deactivated successfully.
Jan 01 11:27:32 ubuntu2204.wang.org systemd[1]: libvirtd.service: Unit process 987 (dnsmasq) remains running after unit stopped.
Jan 01 11:27:32 ubuntu2204.wang.org systemd[1]: libvirtd.service: Unit process 988 (dnsmasq) remains running after unit stopped.
Jan 01 11:27:32 ubuntu2204.wang.org systemd[1]: Stopped Virtualization daemon.
Jan 01 11:27:32 ubuntu2204.wang.org systemd[1]: libvirtd.service: Consumed 9.370s CPU time.

#彻底停掉libvirt服务，发现虚拟机还在运行，只是连接虚拟机的窗口失效
[root@ubuntu2204 ~]#systemctl stop libvirtd libvirtd.socket libvirtdadmin.socket libvirtd-ro.socket
Failed to stop libvirtdadmin.socket: Unit libvirtdadmin.socket not loaded.
[root@ubuntu2204 ~]#virsh list --all
error: failed to connect to the hypervisor
error: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Connection refused
[root@ubuntu2204 ~]#ps aux |grep kvm
root 1247 0.0 0.0 0 0 ? I 10:52 0:02 [kworker/5:0-kvm-irqfd-cleanup]
libvirt+ 1575 5.8 3.2 3853876 532360 ? Sl 11:17 0:55 /usr/bin/qemu-system-x86_64 -name guest=centos7-mooreyxia,debug-threads=on -S -object {"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain-2-centos7-mooreyxia/master-key.aes"} -machine pc-q35-6.2,usb=off,vmport=off,dump-guest-core=off,memory-backend=pc.ram -accel kvm -cpu host,migratable=on -m 2048 -object {"qom-type":"memory-backend-ram","id":"pc.ram","size":2147483648} -overcommit mem-lock=off -smp 2,sockets=2,cores=1,threads=1 -uuid 3492dccc-468d-4fe9-8ec8-b4a251dccf00 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=33,server=on,wait=off -mon chardev=charmonitor,id=monitor,mode=control -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=16,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 -device pcie-root-port,port=17,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 -device pcie-root-port,port=18,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x2 -device pcie-root-port,port=19,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x3 -device pcie-root-port,port=20,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x4 -device pcie-root-port,port=21,chassis=6,id=pci.6,bus=pcie.0,addr=0x2.0x5 -device pcie-root-port,port=22,chassis=7,id=pci.7,bus=pcie.0,addr=0x2.0x6 -device pcie-root-port,port=23,chassis=8,id=pci.8,bus=pcie.0,addr=0x2.0x7 -device pcie-root-port,port=24,chassis=9,id=pci.9,bus=pcie.0,multifunction=on,addr=0x3 -device pcie-root-port,port=25,chassis=10,id=pci.10,bus=pcie.0,addr=0x3.0x1 -device pcie-root-port,port=26,chassis=11,id=pci.11,bus=pcie.0,addr=0x3.0x2 -device pcie-root-port,port=27,chassis=12,id=pci.12,bus=pcie.0,addr=0x3.0x3 -device pcie-root-port,port=28,chassis=13,id=pci.13,bus=pcie.0,addr=0x3.0x4 -device pcie-root-port,port=29,chassis=14,id=pci.14,bus=pcie.0,addr=0x3.0x5 -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":"/var/lib/libvirt/images/centos7-mooreyxia.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":false,"discard":"unmap","driver":"qcow2","file":"libvirt-2-storage","backing":null} -device virtio-blk-pci,bus=pci.4,addr=0x0,drive=libvirt-2-format,id=virtio-disk0,bootindex=1 -device ide-cd,bus=ide.0,id=sata0-0-0 -netdev tap,fd=34,id=hostnet0,vhost=on,vhostfd=36 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:18:b7:d2,bus=pci.1,addr=0x0 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev socket,id=charchannel0,fd=32,server=on,wait=off -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 -chardev spicevmc,id=charchannel1,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0 -device usb-tablet,id=input0,bus=usb.0,port=1 -audiodev {"id":"audio1","driver":"spice"} -spice port=5900,addr=127.0.0.1,disable-ticketing=on,image-compression=off,seamless-migration=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 -device ich9-intel-hda,id=sound0,bus=pcie.0,addr=0x1b -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0,audiodev=audio1 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=2 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=3 -device virtio-balloon-pci,id=balloon0,bus=pci.5,addr=0x0 -object {"qom-type":"rng-random","id":"objrng0","filename":"/dev/urandom"} -device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.6,addr=0x0 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
root 1581 0.0 0.0 0 0 ? S 11:17 0:00 [kvm-nx-lpage-re]
root 1586 0.0 0.0 0 0 ? S 11:17 0:00 [kvm-pit/1575]
root 1781 0.0 0.0 9696 2404 pts/1 S+ 11:33 0:00 grep --color=auto kvm

#重启libvirtd服务，就可以继续连接kvm进行管理
[root@ubuntu2204 ~]#systemctl start libvirtd
[root@ubuntu2204 ~]#virsh list --all
Id Name State
------------------------------------
2 centos7-mooreyxia running
- rocky8 shut off