Security Onion 2 performs daily backups of some critical files so that you can recover your grid from a catastophic failure of the manager. Daily backups create a tar file located in the /nsm/backup/ directory located on the manager. Here is what gets backed up automatically:
/etc/pki/All of the certs including the CA are backed up. Restoring this would allow you to communicate with your salt minions again.
/opt/so/saltstack/local/This includes all minion sls files and customizations.
elasticsearch data is not automatically backed up. This includes things that may be important to you like kibana customizations and cases data. kibana customizations are located in the .kibana indices and cases data is stored in the so-case and so-casehistory indices. To backup this data, there are a few options.
The first option is to enable snapshots with curator to snapshot data to an external storage device such as a NAS.
The second option is to use elasticsearch's built-in support for snapshots: https://www.elastic.co/guide/en/elasticsearch/reference/current/snapshot-restore.html
This option requires that you configure elasticsearch with a path.repo setting where it can store the snapshots. To do this, you can update the elasticsearch salt pillar using something like the following and then restart elasticsearch:
elasticsearch:
config:
path.repo: '/usr/share/elasticsearch/data/repo'Once elasticsearch has the path.repo setting, you should be able to log into kibana and configure snapshots as shown in the link above. Those snapshots will then be accessible in /nsm/elasticsearch/repo/.
A third option is if you have a distributed deployment with elasticsearch clustering, then you can enable replicas to have redundancy in case of a single node failure. Of course, please keep in mind that enabling replicas doubles your storage needs.