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 system metadata volumes, as described in the StorageGRID installation instructions for your Linux operating system. 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 might occur before going on to restart StorageGRID. When you re-create the configuration file for a node, you must use the same name for the replacement node that was used for the node you are recovering.
See the installation instructions for more information on the location of the /var/local volume for a node.