IBM Support

WebSEAL stops authentication after master ldap down even though replica ldap is available

Troubleshooting


Problem

WebSEAL is configured with two ldap servers (high priority master and low priority replica). When master ldap server is power-down, WebSEAL sometimes becomes no authentication mechanism state even though replica ldap is still available.

Symptom

WebSEAL can not notice replica ldap server available during master ldap is down

Cause

WebSEAL is configured to use synchronized ldap connection creation by default. Once replica ldap times out accidentally during master ldap is down, WebSEAL decides both ldap down, and logs 'Authentication mechanism is not available'. In this situation, WebSEAL tries to connect each ldap for checking availability. However, new connection for checking replica server available has very few chance to be picked up. Because only one connection creation is picked up from waiting connection creations against many of master and only one replica. So, WebSEAL can not know if replica ldap becomes available.

Diagnosing The Problem

Following sequence of error messages is recorded in msg__webseald.log

HPDRG0201E Error code 0x51 was received from the LDAP server. Error text: "Can't contact LDAP server".
DPWIV0192W LDAP server MASTER has failed
HPDCO0197W LDAP search request to REPLICA timed out after 10 seconds.
DPWIV0192W LDAP server REPLICA has failed
HPDIA0119W Authentication mechanism is not available.

HPDRG0201E Error code 0x51 was received from the LDAP server. Error text: "Can't contact LDAP server".

The last message is recorded periodically until MASTER ldap becomes available.

Resolving The Problem

Configure WebSEAL to use asynchronized ldap connection creation by setting following parameter.
[ldap]
client-async-auth-binds=yes

The number of the concurrent ldap connection increases with this parameter.

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Document Information

Modified date:
16 June 2018

UID

swg21983062