2.10.2. Backing Up Node Host Files
Backing up certain node host files can help prevent data loss. You can use standard Red Hat Enterprise Linux software, such as
tar or cpio, to perform this backup. Red Hat recommends backing up the following node host files and directories:
/opt/rh/ruby193/root/etc/mcollective/etc/passwd/var/lib/openshift/etc/openshift
Important
Backing up the
/var/lib/openshift directory is paramount to recovering a node host, including head gears of scaled applications, which contain data that cannot be recreated. If the file is recoverable, then it is possible to recreate a node from the existing data. Red Hat recommends this directory be backed up on a separate volume from the root file system, preferably on a Storage Area Network.
If the data from these files is lost, see Section 2.10.3, “Recovering Failed Node Hosts” for instructions on how to recover a failed node host.
Stateless and Stateful Applications
Even though applications on OpenShift Enterprise are stateless by default, developers can also use persistent storage for stateful applications by placing files in their $OPENSHIFT_DATA_DIR directory. See the OpenShift Enterprise User Guide for more information.
Stateless applications are more easily recovered; if an application is treated as stateless, then node hosts can easily be added to and destroyed in your deployment and you can create
cron scripts to clean up these hosts. For stateful applications, Red Hat recommends keeping the state on a separate shared storage volume. This ensures the quick recovery of a node host in the event of a failure.
Note
Developers can also take snapshots of their applications as another way to back up and restore their application data. See the OpenShift Enterprise User Guide for more information.
