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[libvirt-users] Researching why different cache modes result in 'some' guest filesystem corruption..
by vincent＠cojot.name 02 Aug '19

02 Aug '19

Hi All, I've been chasing down an issue in recent weeks (my own lab, so no prod here) and I'm reaching out in case someone might have some guidance to share. I'm running fairly large VMs (RHOSP underclouds - 8vcpu, 32gb ram, about 200gb single disk as a growable qcow2) on some RHEL7.6 hypervisors (kernel 3.10.0-927.2x.y, libvirt 4.5.0, qemu-kvm-1.5.3) on top of SSD/NVMe drives with various filesystems (vxfs, zfs, etc..) and using ECC RAM. The issue can be described as follows: - the guest VMs work fine for a while (days, weeks) but after a kernel update (z-stream) comes in, I am often greeted by the following message immediately after rebooting (or attempting to reboot into the new kernel): "error: not a correct xfs inode" - booting the previous kernel works fine and re-generating the initramfs for the new kernel (from the n-1 kernel) does not solve anything. - if booted from an ISO, xfs_repair does not find errors. - on ext4, there seems to be some kind of corruption there too. I'm building the initial guest image qcow2 for those guest VMs this way: 1) start with a rhel-guest image (currently rhel-server-7.6-update-5-x86_64-kvm.qcow2) 2) convert to LVM by doing this: qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=1048576,lazy_refcounts=off final_guest.qcow2 512G virt-format -a final_guest.qcow2 --partition=mbr --lvm=/dev/rootdg/lv_root --filesystem=xfs guestfish --ro -a rhel_guest.qcow2 -m /dev/sda1 -- tar-out / - | \ guestfish --rw -a final_guest.qcow2 -m /dev/rootdg/lv_root -- tar-in - / 3) use "final_guest.qcow2" as the basis for my guests with LVM. After chasing down this issue some more and attempting various things (build the image on Fedora29, build a real XFS filesystem inside a VM and use the generated qcow2 as a basis instead of virt-format).. ..I've noticed that the SATA disk of each of those guests were using 'directsync' (instead of 'Hypervisor Default'). As soon as I switched to 'None', the XFS issues disappeared and I've now applied several consecutive kernel updates without issues. Also, 'directsync' or 'writethrough', while providing decent performance, both exhibited the XFS 'corruption' behaviour.. Only 'none' seem to have solved that. I've read the docs but I thought it was OK to use those modes (UPS, Battery-Backed RAID, etc..) Does anyone have any idea what's going on or what I may be doing wrong? Thanks for reading, Vincent

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[libvirt-users] Why librbd disallow VM live migration if the disk cache mode is not none or directsync
by Ming-Hung Tsai 01 Aug '19

01 Aug '19

I'm curious that why librbd sets this limitation? The rule first appeared in librbd.git commit d57485f73ab. Theoretically, a write-through cache is also safe for VM migration, if the cache implementation guarantees that cache invalidation and disk write are synchronous operations. For example, I'm using Ceph RBD images as VM storage backend. The Ceph librbd supports synchronous write-through cache, by setting rbd_cache_max_dirty to zero, and setting rbd_cache_block_writes_upfront to true, thus it would be safe for VM migration. Is that true? Any suggestion would be appreciated. Thanks. Ming-Hung Tsai

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[libvirt-users] Libvirt Virtualization Problem
by 王金磊 30 Jul '19

30 Jul '19

Dear Sir/Madam: I use virt-manager to create a new virtual machine(it's name is generic), then I edit generic to set it's cpu_mode as 'host-model', and I start it, but when dumpxml generic, it's cpu_mode is changed as 'custom'. I want to know that why it is? And what's the principle of dumpxml? Thanks! A user of libvirt

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[libvirt-users] virsh command to list CPU,Memory and Storage
by Kaushal Shriyan 30 Jul '19

30 Jul '19

Hi, Is there a way to find out total CPU's, Memory and Storage using virsh command? For example virsh list --all list out all VM's 11 dockerregistry01 running 12 gitlab running Any help will be highly appreciated. Thanks in Advance. Best Regards, Kaushal

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[libvirt-users] <VM LIVE Migration> <Sync conntrack entries>
by bharath paulraj 26 Jul '19

26 Jul '19

Hi Team, I am using QEMU/KVM for launching VMs and libvirt to govern those VMs. I would like to synchronise the connection tracking entries specific to the VM during the VM LIVE migrations. It is required when the firewall is implemented at the host level like libvirt's "network filters". If stateful firewall is enabled, then unless these connection tracking entries are synchronised, all the connections to the VM are lost and all TCP connections should be reestablished. Is there any option already available? I don't think current libvirt hooks are helpful, as VM pause in the source hypervisor and VM on in the destination hypervisor is done by QEMU and it does not wait for any application that needs to sync-up some metadata — In my case, it is conntrack entries. Also I tried with the existing hooks - stop, release, startcpus and nothing worked well. Has anybody came across similar scenario? If yes, how you overcome this? -- Regards, Bharath

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[libvirt-users] Define libvirt network portgroup with native untagged.
by Tanmoy Sinha 26 Jul '19

26 Jul '19

Hi, I have created a libvirt network on top of a OVS bridge (named vlan-br) which receives all VLAN tagged packets, i.e. connected to a trunk port. The definition xml is below. What I want to achieve in the portgroup definition 'trunk-native-1221' is to allow 1221 as untagged/native but rest all VLAN as tagged. The following portgroup definition works, but I don't want to enumerate all the tagged VLANs in the portgroup definition. I understand what libvirt does on the underlying OVS bridge, once a guest interface (say vNetX) is attached to the portgroup is to set the vnetX with tag=1221 and vlan_mode= native-untagged and it sets trunk = [1222,1221,1223,1224]. Now if I go and clear the trunk setting on the OVS bridge for that interface I am able to see both tagged and untagged (1221) packets on the guest. This is exactly what I want to achieve in the libvirt network definition, i.e. have one untagged VLAN and* allow all other VLANs without having to enumerate them in the portgroup definition, as that is hard to maintain. * <network> <name>kvm-core-net</name> <bridge name = 'vlan-br'/> <forward mode = 'bridge'/> <virtualport type='openvswitch'/> ....... <portgroup name='*trunk-native-1221*'> <vlan trunk='yes'> <tag id='1222'/> <tag id='1221' nativeMode='untagged'/> <tag id='1223'/> <tag id='1224'/> </vlan> </portgtroup> ..... </network> Regards Tanmoy Sinha

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[libvirt-users] make install libvirt v5.5.0 failed
by netsurfed 24 Jul '19

24 Jul '19

Hi all: Unable to install libvirt v5.5.0 correctly through the source code which clone from git. The error message is shown below. libtool: install: (cd /home/libvirt/src; /bin/sh /home/libvirt/libtool --silent --tag CC --mode=relink gcc -std=gnu99 -I/usr/include/libxml2 -fno-common -W -Waddress -Waggressive-loop-optimizations -Wall -Wattributes -Wbad-function-cast -Wbuiltin-macro-redefined -Wcast-align -Wchar-subscripts -Wclobbered -Wcomment -Wcomments -Wcoverage-mismatch -Wcpp -Wdeprecated-declarations -Wdiv-by-zero -Wdouble-promotion -Wempty-body -Wendif-labels -Wextra -Wformat-contains-nul -Wformat-extra-args -Wformat-security -Wformat-y2k -Wformat-zero-length -Wfree-nonheap-object -Wignored-qualifiers -Wimplicit -Wimplicit-function-declaration -Wimplicit-int -Winit-self -Winline -Wint-to-pointer-cast -Winvalid-memory-model -Winvalid-pch -Wlogical-op -Wmain -Wmaybe-uninitialized -Wmissing-braces -Wmissing-declarations -Wmissing-field-initializers -Wmissing-include-dirs -Wmissing-parameter-type -Wmissing-prototypes -Wmultichar -Wnarrowing -Wnested-externs -Wnonnull -Wold-style-declaration -Wold-style-definition -Woverflow -Woverride-init -Wpacked-bitfield-compat -Wparentheses -Wpointer-arith -Wpointer-sign -Wpointer-to-int-cast -Wpragmas -Wpsabi -Wreturn-local-addr -Wreturn-type -Wsequence-point -Wshadow -Wsizeof-pointer-memaccess -Wstrict-aliasing -Wstrict-prototypes -Wsuggest-attribute=const -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure -Wswitch -Wsync-nand -Wtrampolines -Wtrigraphs -Wtype-limits -Wuninitialized -Wunknown-pragmas -Wunused -Wunused-but-set-parameter -Wunused-but-set-variable -Wunused-function -Wunused-label -Wunused-local-typedefs -Wunused-parameter -Wunused-result -Wunused-value -Wunused-variable -Wvarargs -Wvariadic-macros -Wvector-operation-performance -Wvolatile-register-var -Wwrite-strings -Wnormalized=nfc -Wno-sign-compare -Wjump-misses-init -Wswitch-enum -Wno-format-nonliteral -fstack-protector-strong -fexceptions -fasynchronous-unwind-tables -fipa-pure-const -Wno-suggest-attribute=pure -Wno-suggest-attribute=const -Werror -Wframe-larger-than=4096 -g -O2 -module -avoid-version -Wl,-z -Wl,nodelete -export-dynamic -Wl,-z -Wl,relro -Wl,-z -Wl,now -Wl,--no-copy-dt-needed-entries -Wl,-z -Wl,defs -o libvirt_driver_vbox.la -rpath /usr/lib/libvirt/connection-driver libvirt_driver_vbox_impl.la libvirt.la ../gnulib/lib/libgnu.la -ldl ) ./.libs/libvirt_driver_vbox_impl.a(libvirt_driver_vbox_impl_la-vbox_common.o): In function `vboxAttachDrives': /home/libvirt/src/vbox/vbox_common.c:1124: undefined reference to `virDomainDeviceFindSCSIController' ./.libs/libvirt_driver_vbox_impl.a(libvirt_driver_vbox_impl_la-vbox_common.o): In function `vboxDomainSnapshotCreateXML': vbox_common.c:(.text+0x698f): undefined reference to `virObjectAutoUnref' vbox_common.c:(.text+0x80fa): undefined reference to `virObjectAutoUnref' ./.libs/libvirt_driver_vbox_impl.a(libvirt_driver_vbox_impl_la-vbox_common.o): In function `vboxDomainSnapshotGetXMLDesc': vbox_common.c:(.text+0xc430): undefined reference to `virDomainSnapshotDefNew' vbox_common.c:(.text+0xc7bc): undefined reference to `virObjectAutoUnref' vbox_common.c:(.text+0xe100): undefined reference to `virObjectAutoUnref' ./.libs/libvirt_driver_vbox_impl.a(libvirt_driver_vbox_impl_la-vbox_common.o): In function `vboxAttachNetwork.isra.17': vbox_common.c:(.text+0x10656): undefined reference to `virDomainNetModelTypeToString' ./.libs/libvirt_driver_vbox_impl.a(libvirt_driver_vbox_impl_la-vbox_common.o): In function `vboxDomainGetXMLDesc': vbox_common.c:(.text+0x1574d): undefined reference to `virDomainHostdevDefNew' collect2: error: ld returned 1 exit status libtool: install: error: relink `libvirt_driver_vbox.la' with the above command before installing it make[3]: *** [install-modLTLIBRARIES] Error 1 make[3]: Leaving directory `/home/libvirt/src' make[2]: *** [install-am] Error 2 make[2]: Leaving directory `/home/libvirt/src' make[1]: *** [install] Error 2 make[1]: Leaving directory `/home/libvirt/src' make: *** [install-recursive] Error 1 Here's how I do it. [root@localhost libvirt]# uname -a Linux localhost.localdomain 3.10.0-693.el7.x86_64 #1 SMP Tue Aug 22 21:09:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux [root@localhost libvirt]# git clone https://libvirt.org/git/libvirt.git [root@localhost libvirt]# cd libvirt [root@localhost libvirt]# git checkout v5.5.0 [root@localhost libvirt]# ./autogen.sh [root@localhost libvirt]# ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var [root@localhost libvirt]# make -j32 [root@localhost libvirt]# make install

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[libvirt-users] Installing QEMU from source causing error
by Probir Roy 22 Jul '19

22 Jul '19

Hi, I am trying to run Qemu-4.0 installed from source code. When I run virt-manager to create a VM, I get the following error: ``` Unable to complete install: 'internal error: process exited while connecting to monitor: 2019-07-19T17:06:35.954242Z qemu-system-x86_64: -enable-kvm: unsupported machine type Use -machine help to list supported machines' Traceback (most recent call last): File "/usr/share/virt-manager/virtManager/asyncjob.py", line 89, in cb_wrapper callback(asyncjob, *args, **kwargs) File "/usr/share/virt-manager/virtManager/create.py", line 2553, in _do_async_install guest.start_install(meter=meter) File "/usr/share/virt-manager/virtinst/guest.py", line 498, in start_install doboot, transient) File "/usr/share/virt-manager/virtinst/guest.py", line 434, in _create_guest domain = self.conn.createXML(install_xml or final_xml, 0) File "/usr/lib/python2.7/dist-packages/libvirt.py", line 3603, in createXML if ret is None:raise libvirtError('virDomainCreateXML() failed', conn=self) libvirtError: internal error: process exited while connecting to monitor: 2019-07-19T17:06:35.954242Z qemu-system-x86_64: -enable-kvm: unsupported machine type Use -machine help to list supported machines ``` I configured the Qemu with following command: ``` ./../configure --prefix=/usr --enable-spice --target-list=x86_64-softmmu --enable-kvm --enable-debug --enable-libssh2 ``` Is it that I missed enabling any configuration while installing Qemu? What is the expected QEMU configuration to run with libvirt? - Probir

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[libvirt-users] virsh edit has no impact on domain
by Probir Roy 22 Jul '19

22 Jul '19

Hi, I am using "virsh edit" to edit a domain. After edit it says >> Domain ubuntu18.04 XML configuration edited. However, reopening the domain with "virsh edit" shows old file. The domain is also turned off. $virsh list --all --persistent Id Name State ---------------------------------------------------- - ubuntu18.04 shut off I have also tried running "virsh define" to set new configuration. $virsh define ubuntu18.04.xml >>> Domain ubuntu18.04 defined from ubuntu18.04.xml However, it also did not change the file. How can I edit the domain config file? OS: Ubuntu 18.04.1 virsh: 4.0.0 -- Probir

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[libvirt-users] domain xml questions
by Vasiliy Tolstov 19 Jul '19

19 Jul '19

Hi! If i want to use bridged network or openvswitch, does guestfwd only works with slirp network? Or how it work in case of using bridge/openvswitch? <devices> <channel type='unix'> <source mode='bind' path='/tmp/guestfwd'/> <target type='guestfwd' address='10.0.2.1' port='4600'/> </channel> </devices> If this cant't work with provided network types, how can i create inside guest serial console on 10 tty that binded to listening unix domain socket on host system? -- Vasiliy Tolstov, e-mail: v.tolstov(a)selfip.ru

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