The Master Grid can manage Grids running NIOS versions that are different from the Master Grid. The oldest version must be no more than three versions earlier than the NIOS version running on the Master Grid. The Master Grid must run the most recent NIOS version among its managed Grids.

Note that when you add a Grid to a Master Grid, you can manage a Grid in strict delegation mode to restrict the IP address space of the managed Grid. When you manage a Grid in this mode, the Grid admin cannot perform any network operation that results in the creation of additional network space. This includes creating a network or network container that is not entirely included in an existing network or network container in the network view and resizing any top level network container. Besides this, adding a Grid to a Master Grid does not restrict the operations of a Grid. An admin can still access and configure the Grid from its Grid Master.

The Master Grid provides a Single Sign On feature that allows you to automatically sign in to selected Grids from the Master Grid, without having to log in to each one. To use this feature, you must first validate your credentials for each of the Grids you need to access in your User Profile. For more information, see /wiki/spaces/mgmadminguide/pages/911180119.

Figure 6.1 Multi-Grid Management

Synchronizing Grid

When a Grid joins a Master Grid, the Multi-Grid Master establishes a VPN connection with the Grid Master and starts synchronizing data from the Grid Master.

The Multi-Grid Master synchronizes monitoring and update status data, including the status of the Grid members and the services that they are running. It also synchronizes IPAM data from the Grid, including the network views, network containers, networks, and extensible attribute definitions. If the Grid manages Microsoft DHCP servers, the synchronized DHCP data from the Microsoft servers is synchronized to the Master Grid as well. When you back up a Master Grid, the backup contains all data synchronized from the managed Grids.

After the initial synchronization, the Multi-Grid Master synchronizes only the data that has been modified since the last successful synchronization. You can view the synchronization status of a Grid by navigating to the Grids tab. For more information, see /wiki/spaces/mgmadminguide/pages/911183110.

Synchronization occurs only between the Multi-Grid Master and the Grid Master. If there is a master promotion in a managed Grid, for sub Grid initiated mode the new Grid Master notifies the Multi-Grid Master that it is the new Grid Master. For the MGM initiated mode, the IP address of the new Grid Master needs to be manually updated. All data communication between the Multi-Grid Master and a Grid Master is encrypted and goes through a VPN tunnel. The Multi-Grid Master can perform multiple synchronizations concurrently with all the Grid Masters of its managed Grids.

The Multi-Grid Master synchronizes regularly with a Grid Master, to ensure the Master Grid has the most current data. In addition, for the sub Grid initiated master grid communication mode some operations on the Grid can trigger a synchronization, such as the addition or update of a member in the Grid, the addition of update of a network view, network container or network, and the update of extensible attributes. Note that the network connection may cause some delays in the synchronization and this may cause some inconsistencies. For example, Grid Manager could display a message indicating that a network already exists when you try to add a network.