This How-to shows you how to migrate your MongoDB data from one cluster to another one. For example how to migrate from your existing on-premise MongoDB cluster to the IONOS MongoDB cluster.
This migration requires some downtime, as you need to stop write operations to your old cluster during dumping the data.
The steps for a migration are as follows:
- 2.Stop writes to old cluster - start of downtime
- 3.Dump data from old cluster using
- 4.Optionally: copy dump
- 5.Restore data into new cluster using
- 6.Use the new cluster - end of downtime
You need one machine that can access the old cluster, that can run
mongodump, and one machine that can access the new cluster, that can run
Both can happen on the same machine. If they're two different machines, you need a way to copy the data dump from one machine to the other.
Both clusters need to be running the same major version. You can see the version in the greeting if you connect with
mongoshor you can query it with
If your old cluster has access control enabled, you need a user with permissions for
findto all databases. Easiest is to grant the
backuprole to the user that you want to use for dumping the data.
You can then verify that you can connect by using the command for
mongodumpmentioned in the section "Dump old data" and then aborting the dump with Ctrl-C.
You need one user with write permissions to all databases that your dump contains.
Additionally you can't restore the users and roles via
mongorestore. So you have to create all the users with their credentials and roles via the IONOS API. You can list all the users and roles in your old cluster with
admindatabase and can then create them in the new cluster according to the documentation on User Management. You can't see the plain text password on your old cluster, so you need to collect them from wherever you stored them.
Caution: The use of
--oplogisn't possible because it requires elevated privileges on restoring. Therefore you need to make sure that no write operations happen during the dump. Otherwise you get an inconsistent dump.
You can dump the data from the old cluster with this command:
mongodump --host="hostname:port" \
--username="username" --password="password" \
--authenticationDatabase "admin" \
Optionally you can limit data using --db, --collection, or --query flags to only dump specific databases, collections, or documents.
You can restore the dumped date in the new cluster with this command:
admin.system.*resources are excluded, since you can't modify users and roles from inside MongoDB in an IONOS MongoDB cluster. You need to use the IONOS API for them.