Technical data

Multiple Single Sign-On Middle Tiers with One Oracle Internet Directory
3-2 Advanced Topologies for Enterprise Deployments
3.3 Multiple Single Sign-On Middle Tiers with One Oracle Internet
Directory
The simplest high availability scenario involves failover within the single sign-on
instance itself, at the middle tier. Adding middle tiers increases scalability and
therefore makes the single sign-on server more available.
In this configuration, a single HTTP load balancer is placed in front of two or more
Oracle HTTP servers. At the backend is one directory server and one identity
management infrastructure database. The purpose of the load balancer is to publish a
single address to single sign-on partner applications while providing a farm of single
sign-on middle tiers that actually service the application requests. The HTTP load
balancer can detect when one of these Oracle HTTP server instances has failed and can
then fail over requests to another instance.
3.3.1 Usage Scenario
The usage scenario presented here assumes the following hypothetical configurations:
■ The directory server and identity management infrastructure database are located
at oid.mydomain.com.
■ There are two single sign-on middle tiers. One is installed on host
sso1.mydomain.com, IP address 138.1.34.172. The other is installed on
sso2.mydomain.com, IP address 138.1.34.173. Both servers listen on non-SSL port
7777. Both are configured to use the directory and identity management
infrastructure database located at oid.mydomain.com.
■ The address of the single sign-on server that is published to partner applications is
sso.mydomain.com, IP address 138.1.34.234. The HTTP load balancer is configured
to listen on sso.mydomain.com, port 80. It load balances user requests between
sso1.mydomain.com and sso2.mydomain.com.
Figure 3–1 shows two single sign-on middle tiers configured to use a single instance of
Oracle Internet Directory.
Notes:
■ In this scenario, the load balancer is listening on port 80, a
non-SSL port number. If the load balancer is configured to use
SSL to interact with the browser, a different port number must
be selected. The default SSL port number is 443.
■ In this scenario and the one immediately following, two single
sign-on middle tiers are used. There can, in fact, be any number
of middle tiers.