Re: recovery of virtual machines on KVM
On Thu, Feb 10, 2011 at 4:39 AM, Ahmed Kamal ahmed.ka...@canonical.com wrote: On 02/09/2011 08:39 PM, Tapas Mishra wrote: I am having a virtualization setup via KVM on a Ubuntu 10.04 64 bit server. A recent dbus update cause a crash of my Host OS.It was a post install script of dbus which ultimately brought everything down. Now I have to basically format the host OS.My cause of concern are the virtual machines which were running on it when the environment was stable.Which were in separate LVM partitions. Some thing like /dev/virtualization/vm1 /dev/virtualization/vm2 /dev/virtualization/vm3 /dev/virtualization/vm4 If some one has experienced recovery of this sort in past let me know what did they do to get things back. All my Virtual Machines were on separate partition and in same VolumeGroup this volume group was on Host OS. Will formatting of HOST os clear the Virtual Machines also in my situation or just be re installing the host and importing the Virtual Machines via a tool such as virt-manager I will be able to get them back. It depends, if the VG is stored on the same disk and you reinstall you might indeed destroy the VMs. Please don't proceed until you're sure of what you're doing Well I can not escape from restoring the production environment Ahmed. How ever by the time of writing this message I have restored every thing. I am sharing it here might help some one who are into similar mess. When you insert the Ubuntu CD it will ask you for partitioning schemes chose the guided partitioning scheme what you have to make sure is not to format the volume group on which all the virtual machines reside. While creating these guests their locations were /etc/libvirt/qemu/*.xml To restore the Virtual Machine go to the /etc/libvirt/ directory of USB backup and which ever file you find missing on the fresh install copy it after you have copied them virsh define /path/to/vm.xml to define that VM in new environment (you will see the VM might run without this but it is advisable to do above thing) My problem was a bit more difficult as the back I had was even buggy so the restoration did not went very smooth.When you are restoring the VMs then I noticed some how permissions andsoftlinks had broken. Once you have finished copying the virtual machines permissions of xml files in /etc/libvirt/qemu/ should be changed to 644 any other file if you see has permission 777 needs to be 644 but the same does not applies to directories. When this was not there I noticed surprisingly the ssh connections to the VMs after copying the respective XML files back were dropping.By the time I wrote down this it was confirmed the backup I had permissions problem. Files in /etc/libvirt/qemu/*.xml on backup had permissions 777 where in the correct permissions should be 700 for these XMLs. I want to mention 2 links if some comes across this thread should help them https://www.redhat.com/archives/virt-tools-list/2011-February/msg00074.html by changing the above xml files permission I observed our SSH connection drop problem also got resolved. How ever due to a DNS resolution failure the DomU social was failing to restart many teams after each reboot of Dom0.So I had to manually login and start it. By now I have successfully restored all the environment. https://www.redhat.com/archives/virt-tools-list/2011-February/msg00060.html -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: recovery of virtual machines on KVM
On Sat, Feb 12, 2011 at 10:15 PM, Tapas Mishra mightydre...@gmail.com wrote: On Thu, Feb 10, 2011 at 4:39 AM, Ahmed Kamal ahmed.ka...@canonical.com wrote: On 02/09/2011 08:39 PM, Tapas Mishra wrote: I am having a virtualization setup via KVM on a Ubuntu 10.04 64 bit server. A recent dbus update cause a crash of my Host OS.It was a post install script of dbus which ultimately brought everything down. Now I have to basically format the host OS.My cause of concern are the virtual machines which were running on it when the environment was stable.Which were in separate LVM partitions. Some thing like /dev/virtualization/vm1 /dev/virtualization/vm2 /dev/virtualization/vm3 /dev/virtualization/vm4 If some one has experienced recovery of this sort in past let me know what did they do to get things back. All my Virtual Machines were on separate partition and in same VolumeGroup this volume group was on Host OS. Will formatting of HOST os clear the Virtual Machines also in my situation or just be re installing the host and importing the Virtual Machines via a tool such as virt-manager I will be able to get them back. It depends, if the VG is stored on the same disk and you reinstall you might indeed destroy the VMs. Please don't proceed until you're sure of what you're doing Well I can not escape from restoring the production environment Ahmed. How ever by the time of writing this message I have restored every thing. I am sharing it here might help some one who are into similar mess. When you insert the Ubuntu CD it will ask you for partitioning schemes chose the guided partitioning scheme what you have to make sure is not to format the volume group on which all the virtual machines reside. While creating these guests their locations were /etc/libvirt/qemu/*.xml To restore the Virtual Machine go to the /etc/libvirt/ directory of USB backup and which ever file you find missing on the fresh install copy it after you have copied them virsh define /path/to/vm.xml to define that VM in new environment (you will see the VM might run without this but it is advisable to do above thing) My problem was a bit more difficult as the back I had was even buggy so the restoration did not went very smooth.When you are restoring the VMs then I noticed some how permissions and softlinks had broken. Once you have finished copying the virtual machines permissions of xml files in /etc/libvirt/qemu/ should be changed to 644 any other file if you see has permission 777 needs to be 644 but the same does not applies to directories. Sorry here the permissions need to be 700 and 644 as I previously told. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: recovery of virtual machines on KVM
On 02/09/2011 08:39 PM, Tapas Mishra wrote: I am having a virtualization setup via KVM on a Ubuntu 10.04 64 bit server. A recent dbus update cause a crash of my Host OS.It was a post install script of dbus which ultimately brought everything down. Now I have to basically format the host OS.My cause of concern are the virtual machines which were running on it when the environment was stable.Which were in separate LVM partitions. Some thing like /dev/virtualization/vm1 /dev/virtualization/vm2 /dev/virtualization/vm3 /dev/virtualization/vm4 If some one has experienced recovery of this sort in past let me know what did they do to get things back. All my Virtual Machines were on separate partition and in same VolumeGroup this volume group was on Host OS. Will formatting of HOST os clear the Virtual Machines also in my situation or just be re installing the host and importing the Virtual Machines via a tool such as virt-manager I will be able to get them back. It depends, if the VG is stored on the same disk and you reinstall you might indeed destroy the VMs. Please don't proceed until you're sure of what you're doing -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
Re: recovery of virtual machines on KVM
On Thu, Feb 10, 2011 at 1:40 PM, Alvin i...@alvin.be wrote: On Wednesday 09 February 2011 19:39:57 Tapas Mishra wrote: I am having a virtualization setup via KVM on a Ubuntu 10.04 64 bit server. A recent dbus update cause a crash of my Host OS.It was a post install script of dbus which ultimately brought everything down. Now I have to basically format the host OS.My cause of concern are the virtual machines which were running on it when the environment was stable.Which were in separate LVM partitions. Some thing like /dev/virtualization/vm1 /dev/virtualization/vm2 /dev/virtualization/vm3 /dev/virtualization/vm4 If some one has experienced recovery of this sort in past let me know what did they do to get things back. All my Virtual Machines were on separate partition and in same VolumeGroup this volume group was on Host OS. Will formatting of HOST os clear the Virtual Machines also in my situation or just be re installing the host and importing the Virtual Machines via a tool such as virt-manager I will be able to get them back. Before your reinstall, dump the configuration of your virtual machines like this: $ virsh dumpxml vm1 vm1.xml After reinstall, redefine the machines $ virsh define vm1.xml It's that simple, but of course you have to leave your LVM volumes in place and make sure your host has the same network interfaces (as defined in the xml). Not possible because the host OS where I was getting this problem I was not even able to login. So what I did is a fresh install and copied the xml files from a backup I had on a USB is that not the correct way to do? I just noticed I am unable to connect to guest OS after this i.e. when the host OS reboots and then I immedialtely do an SSH to the guest from any machine within my network I am able to do so but after 5-10 minutes if I again do an ssh to the same guest then I get host not found error. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
recovery of virtual machines on KVM
I am having a virtualization setup via KVM on a Ubuntu 10.04 64 bit server. A recent dbus update cause a crash of my Host OS.It was a post install script of dbus which ultimately brought everything down. Now I have to basically format the host OS.My cause of concern are the virtual machines which were running on it when the environment was stable.Which were in separate LVM partitions. Some thing like /dev/virtualization/vm1 /dev/virtualization/vm2 /dev/virtualization/vm3 /dev/virtualization/vm4 If some one has experienced recovery of this sort in past let me know what did they do to get things back. All my Virtual Machines were on separate partition and in same VolumeGroup this volume group was on Host OS. Will formatting of HOST os clear the Virtual Machines also in my situation or just be re installing the host and importing the Virtual Machines via a tool such as virt-manager I will be able to get them back. -- ubuntu-server mailing list ubuntu-server@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
