You must restore the grid configuration files for any failed grid nodes, and then validate the grid configuration files and resolve any errors.
You can import any grid node that should be present on the host, as long as its /var/local volume was not lost as a result of the failure of the previous host. For example, the /var/local volume might still exist if you used shared storage for StorageGRID Webscale system metadata volumes, as described in the Installation Guide. Importing the node restores its node configuration file to the host.
If it is not possible to import missing nodes, you must recreate their grid configuration files.
You must then validate the grid configuration file, and resolve any networking or storage issues that may occur before going on to restart StorageGRID Webscale.
See the Installation Guide for more information on the location of the /var/local volume for a node.