Oracle E-business suite: virtual host names solution for R12.2

You have seen me rant about Oracle's provided virtual hostname solution before. If you have not, check it out here. In summary, Oracle's provided solution basically asks you to change the physical hostname of the server to the virtual one, which affects not just Oracle EBS, but everything running on that server.

The Challenge of Virtual Hostnames in Oracle EBS R12.2

In my earlier blog post, I outlined the steps to get virtual hostname working for 11i, R12.0, and R12.1 releases. Oracle EBS R12.2 is a special case, as it uses both 32-bit and 64-bit JDK.

I am happy to tell you that I have a working virtual hostname solution that works with EBS R12.2. Thanks to Maris Elsins who figured this out. In brief, the solution is to compile both 32-bit and 64-bit versions of the fakehostname library and copy them to /usr/lib and /usr/lib64 directories with the same name: libfakehostname.so.1.

Technical Solution: The libfakehostname Strategy

The core of the fix is setting LD_PRELOAD to just libfakehostname.so.1 without the absolute path. This way, both 32-bit and 64-bit binaries pick up the appropriate library corresponding to their specific architecture.

Implementation Steps

Follow these steps to implement the solution on your environment:

• Download the source code:Bash

  [applmgr@apps ~]$ wget https://github.com/nonspecialist/fakehostname/archive/master.zip  [applmgr@apps ~]$ unzip master.zip  [applmgr@apps ~]$ cd fakehostname-master/ 

• Compile the 32-bit library:Bash

  [applmgr@apps fakehostname-master]$ gcc -fPIC -m32 -shared -Wl,-soname,libfakehostname.so.1 -ldl -o libfakehostname.so.1 fakehostname.c 

• Compile the 64-bit library:Bash

  [applmgr@apps fakehostname-master]$ gcc -fPIC -m64 -shared -Wl,-soname,libfakehostname64.so.1 -ldl -o libfakehostname64.so.1 fakehostname.c  [applmgr@apps fakehostname-master]$ ls libfakehostname* libfakehostname64.so.1 libfakehostname.so.1 

• Deploy the libraries:Bash

  # Copy the 32-bit library to /usr/lib  [applmgr@apps fakehostname-master]$ sudo cp libfakehostname.so.1 /usr/lib   # Copy 64-bit library to /usr/lib64 with same name as 32-bit library  [applmgr@apps fakehostname-master]$ sudo cp libfakehostname64.so.1 /usr/lib64/libfakehostname.so.1 

Testing and Verification

Once the libraries are in place, you can verify the redirection of the hostname command using the following environment variables:

Important Note: When setting LD_PRELOAD, do not use the absolute path. Use only the library name so the system can toggle between /usr/lib and /usr/lib64 automatically.

• Set the preload and define the virtual hostname:Bash

  [applmgr@apps ~]$ export LD_PRELOAD="libfakehostname.so.1"   # Test the current physical hostname  [applmgr@apps ~]$ hostname  apps.example.com   # Set and test the fake hostname  [applmgr@apps ~]$ export MYHOSTNAME=virtapps.example.com  [applmgr@apps ~]$ hostname  virtapps.example.com

   

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