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Problem with Hyper-V VSS daemon after upgrading CentOS 6.5 to the latest 6.6
Hello folks,
Before some days CentOS team released a new version for CentOS the 6.6. After some upgrades and tests in a lab environment in the infrastructure, I found some problems with the back up procedures from the System Center DPM.
To be more specific when you try to take a backup from a CentOS 6.6 upgraded image from CentOS 6.5 with Hyper-V Backup Essentials installed (the module/package which is responsible for the Online VSS backup on Linux VMs) you are getting freeze the VM with kernel panic errors on the /var/log/messages file, so the only thing you can do is to hard reset your VM. To avoid all this thing please follow the below instructions:
- You have to remove your integration services so you can install again the new released package for CentOS 6.6 (
hyperv-daemons
) which includes the Online backup utility without any problemrpm -e microsoft-hyper-v kmod-microsoft-hyper-v
. When uninstall completes, please reboot your VM. - After the reboot please login on your VM and install the
hyperv-daemons
package (if you are not root, you must run it with sudo in front of the command)yum install hyperv-daemons
. When install completes, please reboot your VM. - Even after the above instructions completed and the VM is working fine, when you try to backup your VM you will get some errors on your remote console of
hang_task_timeout_secs
and inside the/var/log/messages
file that the Hyper-V VSS: VSS: freeze of/boot: Permission denied
. After a contact with Microsoft and some other on Technet the workaround is below. These problems occurs because of the SELINUX is not disable, actually, it doesn’t allow the hyper-v vss daemon to run. The workaround for this issue is the following:- Disable SELINUX:
vi /etc/selinux/config disable SELINUX ESC :wq reboot
- If you are having strictly policy and for some reason you are using the SELINUX firewall module, run the following command in order to give rights on the hyper-v vss daemon to run on your CentOS
semanage permissive -a hypervvssd_t
- If you get an error “command not found” is because you have to install the python policy core utilities that SELINUX uses. Run the following command
yum install policycoreutils-python
These things above have been tested on Windows Server Hyper-V 2012 R2 and System Center DPM 2012 R2 UR3 and works without any problem (for now) :) Please, bofore do anything on your production Virtual Machines please test it in a lab environment, because some things might not be the same or not fitting with the guide above.
Have a nice day.