Redundant SSO server

You can configure a machine that connects to an existing System Management Server as a Redundant Single Sign-On (RSSO) server. When you select the System Management Server and configure the current machine, the SSO capability from the System Management Server is shared with the RSSO server.

The purpose of setting up RSSO servers is to:

• distribute the workload between RSSO servers

• eliminate single point of failure

  Note: Not all AVEVA products make use of the Redundant SSO Server functionality. Refer to your product documentation to see if this feature is supported.

The following diagram illustrates the working of RSSO servers:

A brief description of the steps in the above workflow is given below:

1. Machine 1 and Machine 2 connect to an existing System Management Server and are configured as RSSO servers using the Configurator.

2. Client A and Client B are registered with the System Management Server.

3. When a workflow is initiated on Client A, it requests a token from Machine 1.

4. Machine 1 sends a token to Client A as if it were sent from the System Management Server.

5. When a workflow is initiated on Client B, it requests a token from Machine 2.

6. Machine 2 sends a token to Client B as if it were sent from the System Management Server.

   Note: The client needs to be configured manually to select the RSSO server with which it will communicate for obtaining a token.

The main difference between the System Management Server and the Redundant Single Sign-On (RSSO) server is that a client can register only with the System Management Server, not with the RSSO server. If you configure RSSO servers, it is recommended that the clients communicate with an RSSO server to obtain a token.

A workflow is initiated and completed on a single RSSO server; it cannot be split between RSSO servers. Subsequent client requests for a token should be made to the RSSO server that issued the original token. In addition, token renewal is also possible only with the same RSSO server.

If the original RSSO becomes unavailable, a new token needs to be requested from another, available RSSO server.

An RSSO server can run independently without the System Management Server, provided that the latest client / resource configurations have already been synchronized.

Note: Configuration such as client registration can only be made with the SMS. RSSO does not accept configuration requests.