I have made some performance and reliability tests for different scenarios on our servers. I have noticed that UCR commands are not available when using a 3rd party Linux distro to rescue and recover an UCS installation by mounting the file system and LVM partitions. In the particular case the dedicated UCS server is hosted in a data center without physical access. After installation, the IP address of the server has been changed to an incorrect one via UMC, and as the resulted problem the server is not reachable through Internet and the user depends on the distros the hosting service provider offers to recover the UCS server.
Using Debian, I mounted the LVM partitions and ran the following commands in the univention-backup directory as the instructions on the Univention wiki page Single Server Backup and Restore under title Restoring the configuration instructed:
tar zxvf ucr-backup_20160319.tgz
sed -e "s/: /='/g;s/$/'/;1,2d;s/^/ucr set /" -i base.conf
sed -e "s/: /='/g;s/$/'/;1,2d;s/^/ucr set --force /" -i base-forced.conf
Unfortunately the server is still not reachable, so the UCR recover process failed or it wasn’t enough. I noticed the command /bin/bash base.conf gave “command not found” errors as it tries to run ucr and the system does not recognize the command:
base.conf: line X: ucr: command not found
base.conf: line Y: ucr: command not found
base.conf: line 620: ucr: command not found
My open questions are:
- As the base.conf runs commands which the live distro OS does not understand, how to recover and restore the UCR variables?
- In addition to UCR, to which configuration variables the change of the IP address of a network device (e.g. eth0, br0) via UMC affects, if any?
- Is it enough to just recover the UCR variables which include the correct IP addresses, or is it required in the particular case to restore some other configuration variables too, such as LDAP and/or Samba related, as instructed in the linked Univention wiki page?