The most straightforward solution arises if we are using a cloud DBaaS solution. In the example of MongoDB, Inc.'s own MongoDB Atlas, we can manage backups from the GUI.

If we host MongoDB in our own servers, we can then use MongoDB, Inc.'s MongoDB Cloud Manager. Cloud Manager is a SaaS that we can point to our own servers to monitor and back up our data. It uses the same oplog that replication uses, and can back up both replica sets and sharded clusters.

If we don't want to (or can't, for security reasons) point our servers to an external SaaS service, we can use MongoDB Cloud Manager's functionality on-premises, using MongoDB Ops Manager. To get MongoDB Ops Manager, we need to get a subscription to the Enterprise Advanced edition of MongoDB for our cluster.