Load Balancing Directory Servers with Access Manager - Simple questions

Hi.

We are in the process of configuring 2 Access Manager instances (servers) accessing the same logical LDAP repository (comprising physically of two Directory Servers working together with Multi-Master Replication configured and tested) For doing this, we are following guide number 819-6258.

The guide uses BigIP load balancer for load balancing the directory servers. However, we intend to use Directory Proxy Server. Since we faced some (unresolved) issues last time that we used DPS, there are some simple questions that I would be very grateful to have answers to:

1. The guide, in section 3.2.10 (To configure Access Manager 1 with the Directory Server load balancer), talks about making changes at 4 places, and replacing the existing entry (hostname and port) with the load balancer's hostname and port (assuming that the load balancer has already been configured). It says that changes need not be made on Access Manager 2 since the LDAPs are in replication, and hence changes will be replicated at all places. However, the guide also states that changes have to be made in two files, namely AMConfig.properties, and the serverconfig.xml file. But these changes will not be reflected on Access Manager 2, since these files are local on each machine.

Question 1. Do changes have to be made in AMConfig.properties and serverconfig.xml files on the other machine hosting Access Manager 2?

Question 2: What is the purpose of putting these values here? Specifically, what is achieved by specifying the Directory server host and port in AMConfig.properties, as well as in serverconfig.xml?

Question 3. In the HTTP console, there is the option of specifying multiple primary LDAP servers, as well as multiple secondary LDAP servers. What is the purpose of these? Are secondary servers attempted when none of the list in the primary list are accessible? Also, if there are multiple entries in the primary server list, are they accessed in a round robin fashion (hereby providing rudimentary load balancing), or are other servers accessed only when the one mentioned first is not reachable etc.?

2. Since I do not have a load balancer setup yet, I tried the following deviation to the above, which, according to me, should have worked. If viewed in the HTTP console, LDAP / Membership / MSISDN and Policy configuration all pointed to the DS on host 1. When I changed all these to point to the directory server on host 2 (and made AMConfig.properties and serverconfig.xml on host 1 point to DS of host 2 as well), things should have worked fine, but apparently Access manager 1 could not be started. Error from Webserver:

[14/Aug/2006:04:30:36] info (13937): WEB0100: Loading web module in virtual server [https-machine_1_FQDN] at [/search]

[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: Exception in thread "EventService" java.lang.ExceptionInInitializerError

[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr:at com.iplanet.services.ldap.event.EventServicePolling.run(EventServicePolling.jav a:132)

[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr:at java.lang.Thread.run(Thread.java:595)

[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: Caused by: java.lang.InterruptedException

[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr:at com.sun.identity.sm.ServiceManager.<clinit>(ServiceManager.java:74)

[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr:... 2 more

In effect, AM on 1 did not start. On rolling back the changes, things again worked like previously.

Will be really grateful for any help / insight / experience on dealing with the above.

Thanks!

[3745 byte] By [ankushkapoor] at [2007-11-26 9:27:27]

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