You can try setting up HA solutions that we support (see docs.hortonworks.com). If you need to setup NameNode on your secondary NameNode you will need to reconfigure you NameNode directories to point to SNN directories, reconfigure fs.default.name to be on SNN node host, and HTTP address to point to SNN as well.
These are general steps. Please let me know if this is helpful. Please also consider that there might be a potential data loss between check pointing interval.