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[libvirt-users] issue with openssh-server running in a libvirt based centos virtual machine
by Adrian Pascalau 27 Jan '18

27 Jan '18

Hi, I have a strange issue in a libvirt environment, and I do not know how to solve it. I have two centos hosts: first one is a physical server called server1, that acts as a host for the second one, called centos1. The centos1 is a virtual machine (VM) running in server1. A linux bridge in forwarding mode is used to connect the centos1 VM network interface to the server1 network interface and to the external network. The centos1 VM and the linux bridge are managed with libvirt (well, the bridge itself in this case is created manually). # virsh net-dumpxml br0 <network connections='1'> <name>br0</name> <uuid>5aaf72a5-023d-4b84-9d7c-d68b0918f620</uuid> <forward mode='bridge'/> <bridge name='br0'/> </network> # brctl show bridge name bridge id STP enabled interfaces br0 8000.fc15b4137688 no eno1 vnet0 Both server1 and centos1 have IP addresses in the same subnet, and both are reachable with ping from every other host in my network. In both server1 and centos1, the openssh-server configuration in /etc/ssh/sshd_config is the default one, and has not been changed. When I ssh with Putty to the physical server server1 IP address, everything works as expected: I get a login prompt, I enter my password and I log in. However, when I use Putty to connect to the centos1 VM, I do not get a login prompt whatsoever. So I think there might be some issue in between the server1 physical interface and my centos VM. I used openssh-server in debug mode, so see where the ssh connection hangs, and here is what I get: [...] debug1: Server will not fork when running in debugging mode. debug1: rexec start in 5 out 5 newsock 5 pipe -1 sock 8 debug1: sshd version OpenSSH_7.4, OpenSSL 1.0.2k-fips 26 Jan 2017 debug1: private host key #0: ssh-rsa SHA256:pEuFQsodwK+0PoRzbVRba1ahHLEpwp8DG2KGQmxOGJk debug1: private host key #1: ecdsa-sha2-nistp256 SHA256:F6HrSNWZhYaU7LMweI+RBviqTCHcTYyMBGPDz5OjT4c debug1: private host key #2: ssh-ed25519 SHA256:aG3V6jjPHXUnNeavbxT/xozqrb5q3yWDkkAmXBCdnGk debug1: inetd sockets after dupping: 3, 3 Connection from x.x.x.181 port 49436 on x.x.x.115 port 22 debug1: Client protocol version 2.0; client software version PuTTY_Release_0.70 debug1: no match: PuTTY_Release_0.70 debug1: Local version string SSH-2.0-OpenSSH_7.4 debug1: Enabling compatibility mode for protocol 2.0 debug1: SELinux support enabled [preauth] debug1: permanently_set_uid: 74/74 [preauth] debug1: list_hostkey_types: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519 [preauth] debug1: SSH2_MSG_KEXINIT sent [preauth] I tried with other windows based ssh clients (MobaXterm) and the same issue happens. I discussed this with people in the openssh mailing list, and they said this issue could most probably be caused by a path MTU/fragmentation problem... Then I moved my centos1 qcow2 image in another physical server called server2, with exactly the same hw specs and network connections, where I have installed an all-in-one OpenStack Pike. The network would be managed with neutron in this case, however I have configured neutron exactly so that the centos1 VM interface connects through a linux bridge (managed by neutron) to the server1 physical network interface, like in the libvirt case. # brctl show bridge name bridge id STP enabled interfaces brqa13eec69-a4 8000.0e7faabad6d4 no eno1 tap8cb53db0-fb tapb24a1cc5-20 Above the tapb24a1cc5-20 is the tap interface towards my centos1 VM. In this case, the Putty issue is gone, and I do not have any issue anymore. If I go back to the libvirt environment in server1, I get the same issue again. So I tend to think that my ssh connection issue is caused by the libvirt and the way networking is configured, however I do not know how to troubleshoot this further anymore. Any help is greatly appreciated. Adrian

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[libvirt-users] Create virtual machine failed using virDomainCreateXML
by netsurfed 25 Jan '18

25 Jan '18

Hi all, When I created a virtual machine using virDomainCreateXML, with virtualport type was openvswitch, and virtual machine creation failed. The error message is: internal error: Child process (/sbin/tc filter add dev vnet110 parent ffff: protocol all u32 match u32 0 0 police rate 0kbps burst 0kb mtu 64kb drop flowid :1) unexpected exit status 2: RTNETLINK answers: Invalid argument The Domain XML file the <interface> section like this: <interface type='bridge'><mac address='52:54:00:71:b1:b6'/><source bridge='ovsbr'/><virtualport type='openvswitch'/><address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/></interface> I looked at the system log and it looked like an ovs port problem: 4560 Jan 22 17:43:33 ubuntu-24 ovs-vsctl: ovs|00001|vsctl|INFO|Called as ovs-vsctl --timeout=5 -- --if-exists del-port vnet110 -- add-port lcs_br_1 vnet110 -- set Interface vnet110 "external- ids:attached-mac=\"52:54:00:21:63:25\"" -- set Interface vnet110 "external-ids:iface-id=\"d0e5c770-6f03-4703-b107-3b074f989b06\"" -- set Interface vnet110 "external-ids:vm-id=\"1c79066e- 46a2-4fa0-984c-a88a7fffcd2b\"" -- set Interface vnet110 external-ids:iface-status=active 4561 Jan 22 17:43:33 ubuntu-24 kernel: [29028.418651] device vnet110 entered promiscuous mode 4562 Jan 22 17:43:33 ubuntu-24 libvirtd[4307]: 2018-01-22 09:43:33.507+0000: 4310: error : virCommandWait:2572 : internal error: Child process (/sbin/tc filter add dev vnet110 parent ffff: pr otocol all u32 match u32 0 0 police rate 0kbps burst 0kb mtu 64kb drop flowid :1) unexpected exit status 2: RTNETLINK answers: Invalid argument 4563 Jan 22 17:43:33 ubuntu-24 libvirtd[4307]: We have an error talking to the kernel 4564 Jan 22 17:43:33 ubuntu-24 kernel: [29028.454028] device vnet110 left promiscuous mode 4565 Jan 22 17:43:33 ubuntu-24 ovs-vsctl: ovs|00001|vsctl|INFO|Called as ovs-vsctl --timeout=5 -- --if-exists del-port vnet110 However, when I use "tc" to manage "vnet*" of an existing virtual machine, it still returns the same error. root@ubuntu-24:~# /sbin/tc filter add dev vnet83 parent ffff: protocol all u32 match u32 0 0 police rate 0kbps burst 0kb mtu 64kb drop flowid :1 RTNETLINK answers: Invalid argument We have an error talking to the kernel Is there any reason for this problem? Thank you very much. Below some information about my machine: libvirt version: 3.4.0 ovs_version: "2.8.90" root@ubuntu-24:~# uname -a Linux ubuntu-24 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

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[libvirt-users] Create virtual machine failed using virDomainCreateXML
by netsurfed 23 Jan '18

23 Jan '18

Hi all, When I created a virtual machine using virDomainCreateXML, with virtualport type was openvswitch, and virtual machine creation failed. The error message is: internal error: Child process (/sbin/tc filter add dev vnet110 parent ffff: protocol all u32 match u32 0 0 police rate 0kbps burst 0kb mtu 64kb drop flowid :1) unexpected exit status 2: RTNETLINK answers: Invalid argument The Domain XML file the <interface> section like this: I looked at the system log and it looked like an ovs port problem. However, when I use "tc" to manage "vnet*" of an existing virtual machine, it still returns the same error. root@ubuntu-24:~# /sbin/tc filter add dev vnet83 parent ffff: protocol all u32 match u32 0 0 police rate 0kbps burst 0kb mtu 64kb drop flowid :1 RTNETLINK answers: Invalid argument We have an error talking to the kernel Is there any reason for this problem? Thank you very much. Below some information about my machine: libvirt version: 3.4.0 ovs_version: "2.8.90" root@ubuntu-24:~# uname -a Linux ubuntu-24 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

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[libvirt-users] Issues Connecting to Remote Host Through SSH
by T A 23 Jan '18

23 Jan '18

Hello, I've been unable to connect to a remote host from within my network using the following argument. virsh/virt-manager -c qemu+ssh://user@host:port/system I've tried libssh & libssh2 as well. Using ssh just prompts me for the host password indefinitely. When using libssh2 the connection is rejected. The host computer is using a custom ssh port which I've added to the above argument. Neither box has an enabled root user. Remote box $ cat /etc/debian_version 9.3 $ ssh -V OpenSSH_7.4p1 Debian-10+deb9u2, OpenSSL 1.0.2l 25 May 2017 $ virsh --version 3.0.0 Host box $ cat /etc/centos-release CentOS Linux release 7.4.1708 (Core) $ ssh -V OpenSSH_7.4p1, OpenSSL 1.0.2k-fips 26 Jan 2017 $ virsh --version 3.2.0 Any help is greatly appreciated.

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[libvirt-users] debug kernel
by llilulu 20 Jan '18

20 Jan '18

libvirt 3.4.0 centos 7.4 Hi: I want usr libvrit create vm to debug linux kernel. Previous , I usr qemu cmd(-gdb tcp::1234) directly. When I search on Internet, I found I can use libvrt xml configure kgdb. <qemu:commandline> <qemu:arg value='-gdb'/> <qemu:arg value='tcp::1234'/> </qemu:commandline> But configure xml use kgdb is differnet on kernel boot. use qemu cmd, before I connect kernel use gdb , the kernel still not boot, When I use gdb connect the vm and put continue cmd on gdb, the kernel will start boot. But I usr libvirt xml configure kgdb, the kernel not stop, I want known that have some way I can use libvirt xml configure kgdb let kernel stop boot before I put continue on gdb? Thanks

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[libvirt-users] debug kernel
by llilulu 20 Jan '18

20 Jan '18

libvirt 3.4.0 centos 7.4 Hi: I want usr libvrit create vm to debug linux kernel. Previous , I usr qemu cmd(-gdb tcp::1234) directly. When I search on Internet, I found I can usr libvrt xml configure kgdb. <qemu:commandline> <qemu:arg value='-gdb'/> <qemu:arg value='tcp::1234'/> </qemu:commandline> But configure xml usr kgdb is differnet on kernel boot. usr qemu cmd, before I connect kernel usr gdb , the kernel still not boot, When I usr gdb connect the vm and put continue cmd on gdb, the kernel will start boot. But I usr libvirt xml configure kgdb, the kernel not stop, I want known that have some way I can use libvirt xml configure kgdb let kernel stop boot before I put continue on gdb? Thanks

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[libvirt-users] How do i programmatically connect to libvirt using tcp
by Shashwat shagun 16 Jan '18

16 Jan '18

Hi, How do i connect to libvirt using tcp with sasl authentication using libvirt-go(Golang) ? -- Regards, Shashwat Shagun

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[libvirt-users] domain xml does not have <target dev='vnetX'/>
by Shashwat shagun 15 Jan '18

15 Jan '18

Hi I'm trying to monitor bandwidth usage of a KVM VM but couldn't find <target dev='vnet0'/> on virsh edit domain_name all i get is this <interface type='network'> <mac address='52:54:00:a1:05:b6'/> <source network='vmango'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> how do i determine which vnet is connected to which domain? -- Regards, Shashwat Shagun

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[libvirt-users] Limiting instructions for guest to help with migration to different host
by R 15 Jan '18

15 Jan '18

Hello, I am migrating a suspended x86-64 guest (disk & state) across different x86-64 hosts with small differences in the available CPU instructions and when I try to resume the guest on the different host libvirt reports an error like this "CPU feature XXX not found" and fails. My question is, is there a way to limit the instructions that are used on the "origin" host when creating the guest to avoid this error? I am pretty sure there is a set of basic instructions that are available across all hosts which could be used for this purpose. Thank you! /R

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Re: [libvirt-users] VM migration upon shutdown in centos 7
by Michal Privoznik 12 Jan '18

12 Jan '18

[Please keed the list CCed] On 01/10/2018 04:43 PM, Raman Gupta wrote: >> Does this command alone succeed? > Yes. I have used this command to migrate VMs successfully, without even > knowing that spelling has changed. > > >> I don't know enough about systemd but maybe it's not waiting for virsh to > finish? > Yes I also think virsh or libvirtd or related service does not wait > before /root/vm_migrate.sh > is called and hence live migration fails. > If I replace Live Migration with a simple ping to peer node in the > vPreShutdownHook.service, then ping goes thru successfully thus indicating > network service was UP at that time. > >> Can you try to get any logs to see what is going on actually? > Jan 8 15:30:58 desktop4 systemd: Stopping Session c1 of user gdm. > Jan 8 15:30:58 desktop4 gdm: Freeing conversation 'gdm-launch-environment' > with active job > Jan 8 15:30:58 desktop4 systemd: Stopped target Sound Card. > Jan 8 15:30:58 desktop4 systemd: Stopping Sound Card. > Jan 8 15:30:58 desktop4 systemd: Stopping LVM2 PV scan on device 8:3... > Jan 8 15:30:58 desktop4 systemd: Removed slice system-getty.slice. > Jan 8 15:30:58 desktop4 systemd: Stopping system-getty.slice. > Jan 8 15:30:58 desktop4 systemd: Stopping Authorization Manager... > Jan 8 15:30:58 desktop4 systemd: Stopping Virtual Machine and Container > Registration Service... > Jan 8 15:30:58 desktop4 systemd: Stopping GlusterFS brick processes > (stopping only)... > Jan 8 15:30:58 desktop4 systemd: Removed slice > system-selinux\x2dpolicy\x2dmigrate\x2dlocal\x2dchanges.slice. > Jan 8 15:30:58 desktop4 systemd: Stopping > system-selinux\x2dpolicy\x2dmigrate\x2dlocal\x2dchanges.slice. > Jan 8 15:30:58 desktop4 systemd: Stopping Availability of block devices... > Jan 8 15:30:58 desktop4 systemd: Stopping Virtual Machine > qemu-1-GsmController. > Jan 8 15:30:58 desktop4 alsactl[837]: alsactl daemon stopped > Jan 8 15:30:58 desktop4 systemd: Stopping Session 1 of user root. > Jan 8 15:30:58 desktop4 systemd: Stopping Manage Sound Card State (restore > and store)... I don't see your service being called. Anyway, look at libvirt-guests.service file. Looks like the following lines cause systemd to wait for a command to finish: [Service] EnvironmentFile=-/etc/sysconfig/libvirt-guests # Hack just call traditional service until we factor # out the code ExecStart=@libexecdir@/libvirt-guests.sh start ExecStop=@libexecdir@/libvirt-guests.sh stop Type=oneshot RemainAfterExit=yes StandardOutput=journal+console TimeoutStopSec=0 > > > > On Wed, Jan 10, 2018 at 8:46 PM, Michal Privoznik <mprivozn(a)redhat.com> > wrote: > >> On 01/05/2018 12:00 PM, Raman Gupta wrote: >>> Hi, >>> >>> I have CentOS 7, two node system which allows live VM migration between >>> them. Live migration triggered from virsh is happily happening. I am >> using >>> GlusterFS for replicating VM disk files. >>> >>> Now I want to automatically do the live migration at the time of >>> reboot/shutdown/halt of the host node and for this I have written a >> systemd >>> service unit [vPreShutdownHook.service] and placed the live migration >>> command in a migrate script which is invoked from this service unit. The >>> migrate script is invoked but migration does not happen. >>> If someone has some idea please help me to migrate VM upon shutdown. >>> >>> >>> ######## vPreShutdownHook.service ############### >>> >>> [Unit] >>> Description=vPreShutdownHook >>> Requires=network.target >>> Requires=libvirtd.service >>> Requires=dbus.service >>> Requires=glusterd.service >>> Requires=glusterfsd.service >>> DefaultDependencies=no >>> Before=shutdown.target reboot.target >>> >>> [Service] >>> Type=oneshot >>> RemainAfterExit=true >>> ExecStart=/bin/true >>> ExecStop=/root/vm_migrate.sh >>> >>> [Install] >>> WantedBy=multi-user.target >>> >>> >>> ########## Command to migrate ############ >>> /usr/bin/virsh migrate --verbose --p2p --tunneled --live --compressed >>> --comp-methods "mt" --comp-mt-level 5 --comp-mt-threads 5 >>> --comp-mt-dthreads 5 MY_VM qemu+ssh://root@$node2/system >> >> Does this command alone succeed? >> BTW: unless really needed --live will only make the migration take longer. >> >> I don't know enough about systemd but maybe it's not waiting for virsh >> to finish? Can you try to get any logs to see what is going on actually? >> >> Michal >> > Michal

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