Hi n c,
As long as you have the same configs, fsimage and edits, you should be able to just put these files on another machine running namenode (same version of course). Make sure the new machine hostname matches the previous machine that went down so that the datanodes can reach the new machine. Launch namenode and force into safemode. Verify if all the blocks are accounted for by running fsck. Once you verify all the blocks and no corruption, go ahead and get out of safemode. As always, test on dev environment so you can also make note of specific steps you need to take in your environment. Hope that helps.
Regards,
Robert
