Planning for Cisco CSS Controller

Note:
The Cisco CSS Controller component is shipped with Version 7.0 of Load Balancer for IPv4, but this component might not support newer hardware. Consult the prerequisites page for supported hardware: http://www.ibm.com/support/docview.wss?rs=180&uid=swg27006921

This chapter describes what a network planner should consider before installing and configuring the Cisco CSS Controller component.

This chapter includes:

System requirements

For hardware and software requirements, refer to the following Web page: http://www.ibm.com/support/docview.wss?rs=180&uid=swg27006921

You will also need

Planning considerations

The Cisco CSS Controller manages a set of switch consultants. Each consultant determines weights for services that are load balanced by a single switch. The switch for which the consultant provides weights is configured for content load balancing. The consultant uses the SNMP protocol to send the calculated weights to the switch. The switch uses the weights to select a service for the content rule it is load balancing when the load balancing algorithm is weighted round-robin. To determine weights, the consultant uses one or more of the following pieces of information:

See the Cisco Content Services Switch Getting Started Guide for a description of content load balancing and for detailed information on configuring the switch.

For a consultant to obtain the information it needs to determine service weights, you must have:

Placement of the consultant in the network

As indicated in Figure 23, the consultant can be connected to the network behind the switch or switches for which it provides weights. Some parameters must be configured on the switch and some on the controller to enable connectivity between the controller, the switch, and the services.

In Figure 23:

Refer to the Cisco Content Services Switch Getting Started Guide for detailed information about configuring VLANs and IP routing on the switch.

Figure 23. Example of a consultant connected behind the switches
Consultant behind the switches

You can manage the Cisco CSS Controller using any of the following interfaces:

For remote management, in Figure 24 :

Refer to Cisco Content Services Switch Getting Started Guide for detailed information.

Figure 24. Example of consultant (with optional high availability partner), configured behind switch with user interface in front of switch
Consultant behind switch; user interface in front of switch, optional high availability partner

High availability

Controller high availability enhances the fault tolerance capabilities of Load Balancer. Designed with packet-forwarding high availability in mind, controller high availability involves two controllers running simultaneously, one in the primary role, the other in the secondary role.

Each controller is configured with identical switch information, and only one controller is active at a time. This means that, as determined by the high availability logic, only the active controller calculates and updates the switch with new weights.

Controller high availability communicates with its partner using simple user datagram protocol (UDP) packets over an address and port that you configure. These packets are used to exchange information between controllers as it pertains to high availability (reach information), and to determine partner controller availability (heartbeats). If the standby controller determines that the active controller has failed for any reason, the standby controller takes over from the failed active controller. The standby controller then becomes the active controller, and begins calculating and updating the switch with new weights.

In addition to partner availability, reach targets can be configured for high availability. Controller high availability uses the reach information to determine which controller is active and which is standby. The active controller is the controller that can ping more targets and is reachable from its partner.

See High availability for more information.

Calculating weights

If the consultant determines that a service is unavailable, it will suspend that service on the switch to prevent the switch from considering the server when it load balances requests. When the service is available again, the consultant activates the service on the switch so that it is considered for load balancing requests.

Problem determination

Cisco CSS Controller posts entries to the following logs:

These logs are located in the following directories:

In each log, you can set the log size and logging level. See Using Load Balancer logs for more information.