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About Siebel Gateway Clustering

Siebel CRM supports an optional native clustering feature for Siebel Gateway to provide high availability benefits to Siebel CRM customers. This feature works at the software level and is the preferred and recommended approach for clustering the Siebel Gateway. This topic is part of Configuring the Siebel Gateway Cluster.

NOTE:  This feature, first provided in Siebel CRM 18.5 Update, became generally available as of Siebel CRM 18.7 Update.

The clustering feature supports both the Siebel Gateway service (application container) and the Siebel Gateway registry (Apache ZooKeeper). You might choose to use Siebel Gateway clustering only for your production environment, for example. Further, you can use clustering for only the Siebel Gateway service, or only the Siebel Gateway registry. However, it is recommended to configure clustering for both of them.

Siebel Management Console supports a new profile type, the Siebel Gateway cluster profile, and a new step to deploy the cluster profile.

To use Siebel Gateway clustering, you perform the following tasks:

1. Install at least three instances of Siebel Gateway on different nodes (that is, install both Siebel CRM 17.0 and Siebel CRM 18.12 Update). You can collocate a Siebel Gateway with a Siebel Server, for example, as noted in Installing Siebel CRM.

   In a migration installation case, you perform a migration installation for the existing installed Siebel Gateway. Then you perform new installations for all other Siebel Gateway nodes that you require.

2. (New deployment only) Configure and deploy the primary Siebel Gateway node in Siebel Management Console, as described in Configuring the Siebel Gateway and Security.

   The first Siebel Gateway installed and configured is the primary node. This task does not apply in a migration installation case, because the existing Siebel Gateway is migrated and serves as the primary Siebel Gateway.

3. Start the Siebel Management Console.
4. Configure a Siebel Gateway cluster profile in Siebel Management Console, as described in Creating a Siebel Gateway Cluster.

   In the cluster profile, you specify values for Registry Client Port, Registry Follower Port, and Registry Leader Port. For Registry Client Port, you specify the same Siebel Gateway registry port number that you specified when you configured the primary Siebel Gateway, as described in Configuring the Siebel Gateway and Security. The Registry Follower Port and Registry Leader Port are used for internal communication between Siebel Gateway nodes.

5. (Required as precaution) Back up the Siebel Gateway registry, as described in Siebel System Administration Guide.
6. Deploy the Siebel Gateway cluster profile, specifying all participating nodes, as described in Deploying the Siebel Gateway Cluster.

After cluster deployment, all applicable nodes function as part of the cluster, for the Siebel Gateway service and the Siebel Gateway registry, as applicable. The Siebel Deployment screen in Siebel Management Console shows all of the components of the Siebel Gateway cluster, within the overall deployment hierarchy. The item Gateway Cluster has child items Gateway Service Cluster and Gateway Registry Cluster, each of which has child items representing the participating nodes. Deployment status is shown for each cluster node. The primary node is highlighted, for your reference. If deployment does not succeed for the minimum number of nodes required for each cluster, then cluster deployment fails and the system uses the primary Siebel Gateway.

Siebel Application Interface and Siebel Server function as clients for the Siebel Gateway service. When a Siebel Gateway service cluster is deployed, then Siebel Application Interface or Siebel Server can communicate with any of the nodes in the Siebel Gateway service cluster, and route requests to each available node, in a round-robin manner.

Similarly, the Siebel Gateway service that receives a request functions as a client for the Siebel Gateway registry. When a Siebel Gateway registry cluster is deployed, then the Siebel Gateway service can communicate with any of the nodes in the Siebel Gateway registry cluster, and routes each request to an available node, in a manner determined by ZooKeeper.

The specific requirements for Siebel Gateway clustering differ for the Siebel Gateway service and the Siebel Gateway registry. Although Siebel Gateway service clustering requires a minimum of two nodes, Siebel Gateway registry clustering requires a minimum of three nodes and an odd number of nodes: three, five, and so on. For the Siebel Gateway service cluster, you can include all the same nodes that you include for the registry cluster, or include only a subset of these nodes. Optionally, you can deploy the Siebel Gateway service cluster and registry cluster on different nodes.

If an individual node goes down within the Siebel Gateway cluster, then the Siebel Application Interface or Siebel Server client connection switches to another available node, within the tolerance allowed by the cluster. After any Siebel Gateway cluster node goes down, when it is restarted, the node will again participate in the cluster.

For a Siebel Gateway service cluster, all but one node can go down, and the Siebel Gateway service will still function.

However, for the Siebel Gateway registry cluster, among those nodes configured as part of the cluster, a simple majority of running instances is required in order for the registry cluster to function: for example, two out of three nodes, or three out of five nodes.

NOTE:  You can configure and deploy the Siebel Gateway cluster, or change an existing cluster such as to add or remove nodes, at any time after the primary Siebel Gateway has been configured in Siebel Management Console and the participating nodes have been installed. In general, it is recommended to deploy the Siebel Gateway cluster before you configure the Siebel Enterprise, Siebel Server, and so on. If you deploy the Siebel Gateway cluster after you configure the rest of the Siebel environment, then afterward you must restart the application containers for all of the other services.

If the Siebel Gateway cluster deployment fails (for example, if two out of three Siebel Gateway registry cluster nodes go down), then the system reverts to the non-clustered architecture: Siebel Application Interface and Siebel Server connect to the primary Siebel Gateway node, assuming it is running.

The Siebel Gateway cluster uses an active-active model, in which actions can originate in any available node. For the Siebel Gateway registry cluster, updates are replicated to the other nodes, thus keeping all of the cluster nodes synchronized. The active-active model enables the cluster nodes to participate in load balancing of Siebel Gateway activities.

Related Topics

About Configuring Siebel CRM

Running the Siebel Management Console

Configuring the Siebel Gateway and Security

Removing the Siebel Gateway

Related Books

Siebel Deployment Planning Guide

Siebel System Administration Guide