Start Mongo Replicaset up again after hard power off or restarting all hosts or containers

forceMongoMaster.js

/**
 * This script forces the first node in the config list to be master
 */
cfg = rs.conf()
cfg.members[0].priority = 1
cfg.members[1].priority = 0.5
cfg.members[2].priority = 0.5
rs.reconfig(cfg, {force: true})

reinstateMongoReplicaset.js

// This one liner will force the replica set to restart re-election if hostnames haven't changed.
rs.reconfig(rs.conf(), {force: true});

/**
 * If hostnames need to be reconfigured for whatever reason, use the following lines to readjust the replica set configuration
 */
// cfg =  rs.conf();
// cfg.members[0].host = "192.168.0.1:27017"
// cfg.members[1].host = "123.123.123.123:27017"
// cfg.members[2].host = "mongodb-hostnames-work-here-too:27017"
// rs.reconfig(cfg, {force: true});