Understanding the Linked Mode options for vCenter Server 5.1.x and 5.5.x

Products

VMware vCenter Server

Issue/Introduction

For Linked Mode to work in either a 5.1.x or 5.5.x vCenter Server deployment, the SSO Domain ID must be the same for all instances of vCenter Server that are going to be a member of a Linked Mode group.

Note: The SSO Domain ID is also referenced as the vSphere Authentication Domain in some of the VMware documentations.
Only same build number of vCenter Server must be joined in a Linked Mode group.
When upgrading vCenter Servers, isolate the vCenter Server from the Linked Mode group first, then perform the upgrade. Repeat this process until all of the vCenter Servers are upgraded to the same build number and then establish the Link Mode group.

Note: Linked Mode is not available with the vCenter Server virtual appliance.

Environment

VMware vCenter Server 5.5.x
VMware vCenter Server 5.1.x

Resolution

These are a few examples in which vCenter Server Linked Mode may or may not be available within your environment.

Note: Linked Mode is not available with the vCenter Server virtual appliance.

One standalone SSO node with multiple vCenter Servers registered (Example 1)

In this example:

There is a single SSO node deployed as a standalone node with multiple vCenter Servers registered to this SSO node.
There is one SSO Domain ID.
All vCenter Servers may join a Linked Mode group.

Two standalone SSO nodes with one or more vCenter Servers registered to each node (Example 2)

In this example:

There are two SSO nodes.
Each node is deployed as a standalone node.
There are two different SSO Domain IDs, one for each SSO node. Only vCenter A and vCenter B may join a Linked Mode Group.
vCenter C may not join either vCenter A or vCenter B because they are registered to a different SSO node that has a different SSO Domain ID.

Three SSO nodes deployed in a Multisite deployment (Example 3)

Notes:

In vCenter Server 5.1, replication between SSO nodes is a manual process. For more information, see VMware vCenter Server 5.1.x Multisite Single Sign-On deployment best practices (2042849).
In vCenter Server 5.5 and later, the replication between SSO nodes is automatic and occurs every 30 seconds.

In this example:

There are three SSO nodes deployed in a Multisite deployment.
There is one SSO Domain ID.
All three vCenter Servers may join a Linked Mode Group.

Two SSO nodes deployed in a Multisite deployment with one standalone SSO node (Example 4)

Notes:

In vCenter Server 5.1, replication between SSO nodes is a manual process. For more information, see VMware vCenter Server 5.1.x Multisite Single Sign-On deployment best practices (2042849).
In vCenter Server 5.5 and later, the replication between SSO nodes is automatic and occurs every 30 seconds.

In this example:

There is one SSO node deployed as a standalone node and two SSO nodes deployed in a Multisite deployment.
There are two SSO Domain IDs, one for the Multisite deployment and one for the standalone SSO node.
Only vCenter B and vCenter C may join Linked Mode.

Three SSO nodes deployed in a High Availability (HA) deployment that has been correctly configured behind a Load Balancer (Example 5)

In this example:

There are three SSO nodes deployed in a High Availability (HA) deployment and are correctly configured behind a Load Balancer.
There is one SSO Domain ID.
All three vCenter Servers may be joined into a Linked Mode group.

For more information, see the Linked Mode Considerations for vCenter Server section in the vCenter Server and Host Management Guide.

Additional Information

VMware vCenter Server 5.1.x Multisite Single Sign-On deployment best practices
vCenter Server 5.1.x および 5.5.x の [リンクモード] について