Deployment Example 1: Access Manager 7.0 Load Balancing, Distributed Authentication UI, and Session Failover

Chapter 1 Key Features and Constraints

This document provides instructions for installing and configuring a common Sun Java System Access Manager 7 2005Q4 solution that incorporates load-balancing, distributed authentication UI, and policy agents.

1.1 Key Features of This Deployment Example

All components such as Directory Servers, Access Manager Servers, Distributed Authentication UI servers, and Policy Agents are redundant to achieve high availability.
Both Web Policy Agents and J2EE Policy Agents are used to protect resources in the environment.
All components use load-balancing for system failover and for high availability.
Each Directory Server contains three instances: one named ds-config for storing Directory Server configuration, one named am-config for storing Access Manager configuration, and one named am-users for storing Access Manager users. The am-users instance serves as the LDAPv3 user data store.
The environment includes one service access interface for external users and agents, and a separate service access interface for internal administrators.
Actual firewalls were not used in this deployment. However, critical components such as Access Manager and Directory Server can be protected by three firewalls as illustrated in Figure 1–1. In this illustration, only simple components and interfaces are exposed to the Internet in a minimally-secured zone known as the DMZ.
Access Manager servers are reconfigured to run as non-root users.
The environment is configured for system failover capability. System failover ensures that when one Access Manager server goes down, requests are redirected to a second Access Manager server. It is important to note that system failover, by itself, does not ensure Access Manager session failover.
The environment is configured for session failover capability. Session failover ensures that when the Access Manager server where the user's session was created is stopped, the user's session token can still be retrieved from a backend session database. The user is continuously authenticated, and does not have to log into the system again unless the session is invalidated. For example, a session is invalidated when the logout occurs or when the session expires.
An existing LDAPv3 user data store is integrated into the environment.
SSL is terminated at the load balancer for Access Manager servers and at the load balancer for Access Manager Distributed Authentication UI servers. In this deployment example, communication to each of these load balancers is in SSL, and communication between the load balancer and the server is non-SSL.
Each policy agent in the deployment is configured with a unique agent profile used by the agent to authenticate itself to Access Manager.
The Distributed Authentication UI servers use a custom user profile to authenticate to Access Manager instead of a default of amadmin or UrlAccessManager.

1.2 System Environment and Architecture

The following components comprise the system environment and architecture described in this document:

Network Connectivity: Although firewalls were not actually implemented when setting up this deployment example, in this environment the best practice is to use three firewalls which form three distinct security zones as illustrated in Figure 1–1. One zone would be completely secured, protected by all three firewalls, and would used for internal traffic only. Two minimally-secured zones, also known as DMZs, would be protected by only two firewalls. One minimally-secured zone would be used for internal traffic only, and the second minimally-secured would be used for external traffic. Direct access to individual Access Manager servers would be allowed for internal administrators only if permitted by firewall rules. For more information on specific firewall rules, see the section 2.4 Firewall Rules in this document.
Distributed Authentication UI servers: The Distributed Authentication UI servers provide a thin presentation layer for user authentication. The purpose of the Distributed Authentication UI servers is to protect the Access Manager servers from exposure in the minimally-secured DMZ. During user authentication, a Distributed Authentication Module passes the user's credential to the Access Manager server for verification. The user does not have direct network access to Access Manager servers.

Figure 1–1 System Architecture

Figure illustrates flow from Internet through
multiple load balancers to Access Manager servers.

Protected Resources

Protected resources are the Web Servers or Application Servers to which you want to restrict access. For example, your Human Resources Department might use Applications Servers to host applications and Web Servers to host content. Some of the hosted information must be made available to external benefits administration vendors. External vendors might include health care providers or stock administrators who must access employee information in order to coordinate benefits. The external vendors access the protected resources through an external-facing load balancer. Other information must be restricted to only internal Human Resources administrators. Internal administrators access the protected resources through an internal-facing load balancer.

J2EE Policy Agents and Web Policy Agents

Policy agents restrict access to content or applications hosted on the protected resources. The policy agents intercept HTTP requests from external users, then communicate with the Access Manager servers. If the user presents proper credentials and can be authenticated by the Access Manager server, Access Manager allows the user to access the protected resource. The policy agents are deployed with a load balancer in front of them.

Access Manager Servers

Two separate Access Manager servers provide core Access Manager functionality. Both servers share the same configuration. Both servers store their configuration through a single load balancer deployed in front of the two Directory Servers.

The Access Manager servers are hosted behind the internal firewall and outside the DMZ. The load balancer and two Access Manager servers together provide high data availability within the infrastructure.

Directory Servers

Two Directory Server instances provide the storage for Access Manager configuration information. This includes information about services, policies, and more. Both Directory Server data instances are master replicas that engage in multi-master replication (MMR). MMR allows data to be synchronized in real time between two directories. This synchronization provides high availability to the Access Manager layer.

Load Balancers

Load balancers in this environment enable system failover and high server availability for optimized performance. Multiple virtual load balancers in this deployment example were aggregated into a single unit of load balancing hardware.

Distributed Authentication UI Load Balancer: This external-facing load balancer exposes the remote, web-based Access Manager interface for user authentication, self-registration, and policy agent authentication.
Policy Agents Load Balancers: Policy agents are deployed with external-facing load balancers in front of them. The policy agents then communicate with Access Manager servers through an internal-facing load balancer.
Access Manager Load Balancer: This internal-facing load balancer exposes the web-based Access Manager administration console to internal administrators. Alternatively, internal administrators can also bypass the internal-facing load balancer and log in directly to an Access Manager administration console.
Directory Server Load Balancer: The load balancer in front of the Directory Servers provides round-robin load balancing for Directory Server access, and detects individual Directory Server failures and recovery. Failed servers are taken out of the load balancer list. The load balancer also provides a single virtual Directory Server host name to the Access Manager servers.

Message Queue Broker Cluster

In this deployment example, Access Manages uses two Message Queue instances to form a cluster. The cluster acts as a communications broker, and uses the Berkeley DB by Sleepycat Software, Inc. as the session store database. When session failover is enabled, and an Access Manager server goes down, the available Access Manager server can retrieve the user's session token from one of the Message Queues in the cluster. This ensures that the user remains continuously authenticated, and allows the user to access to the Protected Resources without having to re-authenticate.

1.3 System Behaviors

The following sequence describes the interaction between the various components in this Deployment Example. These interactions are also illustrated in the following pages. The numbered steps here correspond to the numbers in the figures on the following pages.

A user attempts to access the J2EE application hosted by Protected Resource 1 and by Protected Resource 2 through Load Balancer 6. Load Balancer 6 redirects the user to Protected Resource 1.
The J2EE Policy Agent intercepts the request and checks for the Access Manager cookie.
If the Access Manager cookie is not found, the J2EE Policy Agent redirects the user to Load Balancer 4, the load balancer for the Distributed Authentication UI servers.
Load Balancer 4 routes the user request to Authentication UI Server 2.
Authentication UI Server 2 displays a login page to the user.
The user enters credentials on the login page.
Authentication UI Server 2 passes the credentials to Load Balancer 3.
Load Balancer 3 routes the Authentication UI 2 request to Access Manager 1 for validation.
Access Manager 1 sends the Authentication UI 2 request to Load Balancer 2. Load Balancer 2 handles Directory Server requests for user data.
Load Balancer 2 routes the Authentication UI 2 request to Directory Server 2 where validation takes place.
After successful authentication, Access Manager 1 sends the Authentication UI 2 request back to the J2EE Policy Agent. The J2EE Policy Agent receives the request and checks for the Access Manger cookie.
When a cookie is found, the J2EE Policy Agent sends a session validation request to the Access Manager Load Balancer 3.
The Access Manager Load Balancer 3 forwards the request to the Access Manager 1 where the session originated. Cookie-based persistency and routing enables Access Manager to route the request properly.
Access Manager 1 sends a response back to the J2EE Policy Agent.
If the session is not valid, the J2EE Policy Agent would redirect the user to the Distributed Authentication UI server.
In this example, J2EE Policy Agent receives the response back as a valid session. When the session is valid, the J2EE Policy Agent sends a policy request to Access Manager servers' Load Balancer 3.
Access Manager 1 conducts the policy evaluation.
Based on the policy evaluation, the J2EE Policy Agent either allows access to the resource or denies access to the resource. In this example, the user is allowed access to the Application Server.

Figure 1–2 Request for Access

Incoming request goes to the J2EE Policy Agent,
to Load Balancer 4, and then to Distributed Authentication UI server.

In this figure, a user attempts to access a protected application. The J2EE Policy Agent intercepts the access request. The Authentication UI is invoked. The Authentication UI server displays a login page to the user.

Figure 1–3 Authentication

In this figure, the user credentials are passed to Access Manager 1. Access Manager 1 checks the user credentials against Directory Server.

Figure 1–4 Access Granted

Access Manager authenticates the user, and the J2EE Policy Agent determines that the user's session is valid. The J2EE Policy Agent sends a second request to Access Manager for policy evaluation. Based on the results of the policy evaluation, the J2EE Policy Agent allows access to the application server. Access Manager continues to manage the session until the user logs out.