Upgrading servers in a topology

An update to the current server release includes the introduction of a topology registry, which stores information that was stored previously in the admin backend, such as server instances, instance and secret keys, server groups, and administrator user accounts.

Before you begin

Before you can update and migrate the admin backend, the following conditions must be satisfied:

Run the update command and provide LDAP authentication options to the peer servers of the server being updated. The update command connects to the peer servers of the server being updated to obtain the necessary information to populate the topology registry.
On every server in the topology, configure the encryption protocol requested, either plain, TLS, StartTLS, or SASL, for an LDAP connection.
Ensure the LDAP credentials are present on every server in the topology.
Ensure the users related to the LDAP credentials have permissions to read from the admin backend and the config backend of every server in the topology. For example, you can use a root DN user that has inherit-default-privileges set to true, such as the cn=Directory Manager user, that exists on every server.
The instance name is set on every server and is unique across all servers in the topology. The instance name is a server’s identifier in the topology. After all servers in the topology have been updated, each server is uniquely identified by its instance name. After the name is set, it cannot be changed.
If needed, use the following command to set the instance name of a server before the update.

$ bin/dsconfig set-global-configuration-prop \ --set instance-name:uniqueName

Steps

To make clustered configuration changes in a mixed-version cluster:

Choose from:

Update each server to the same version.

Temporarily split up the cluster by changing the cluster-name property on the server instance configuration objects.

Changes to clustered configurations are not allowed in mixed-version clusters. This applies to configuration in the cn=Cluster,cn=config subtree and only applies to servers with matching cluster names.

Make clustered configuration changes again to mirror these changes across the topology.

Result:

When all of these conditions are met, the cluster-wide configuration is synchronized on all servers in the topology.

Older versions have some topology configuration under the cn=cluster,cn=config JSON attribute and field constraints. These items do not support mirrored cluster-wide configuration data. In an update, avoid custom configuration changes on a server being overwritten with the configuration on the mirrored subtree primary.

To synchronize the cluster-wide configuration data across all servers in the topology, run the config-diff command on each pair of servers to determine the differences, and use dsconfig to update each instance using the config-diff output.

Example:
```
$ bin/config-diff --sourceHost hostName \
  --sourcePort port \
  --sourceBindDN bindDN \
  --sourceBindPassword password \
  --targetHost hostName \
  --targetPort port \
  --targetBindDN bindDN \
  --targetBindPassword password
```