/admin/datastore?op=ping checks the aliveness of a Dgraph and returns a lightweight message.
You can view the Dgraph Statistics page to check whether the Dgraph is running and accepting queries, but that comes with some overhead. A quicker way to check the aliveness of a Dgraph is by running the ping command.
Because ping requests are given the highest priority and are processed synchronously (as they are received), a ping response time is independent of the number of outstanding requests in the Dgraph.
dgraph Web07:5556 responding at Wed Mar 28 15:35:27 2012You can use this operation to monitor the health or heartbeat of the Dgraph, and as a health check for load balancers.