Make OS to look for sudoers to different path

This is for Solaris-11.
We have our customize sudoers to fulfill requirements and that is placed in /usr/local/etc/. Already removed /etc/sudoers, which comes with OS default. But OS it still looking for /etc/sudoers when I give sudo command. How to make him look into /usr/local/etc ?

root@prod_ora08 # ls -l /etc/sudoers /usr/local/etc/sudoers
/etc/sudoers: No such file or directory
-r--r-----   1 root     root       21431 May 29 13:47 /usr/local/etc/sudoers
root@prod_ora08 # sudo
sudo: unable to stat /etc/sudoers: No such file or directory
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin
root@prod_ora08 #

That is a hardcoded path, as it should be. You would have to modify the source code and recompile.

I believe there should be a way (or workaround), as all of other servers have sudoers at this path only.

Two quick options that may work are to create a symlink:

ln -svf /usr/local/etc/sudoers /etc/sudoers

Or use the #include option to point to the other location. Create an empty /etc/sudoers file and add the following line:

#include /usr/local/etc/sudoers

This is sudo, it has to be hardcoded. You can't just have people telling a login system to use a non-system config file, and you don't open a config file to figure out what file your config is.

Grep for /etc/sudoers and you'll find it in your sudo binary.

/usr/local/ is indeed where custom built things tend to go, so I remain confident they have a custom built sudo. Perhaps they found a way to deploy the same custom build across multiple machines. Perhaps the build is still sitting around in one of them.

Yes, I am close now. We install SMCsudo in /usr/local and copy sudoers to /usr/local/etc/. Since base directory of SMCsudo will be /usr/local, it will look to its etc for sudoers.
But that we used to do on Solaris-10. I am not if this package is available for Solaris 11 or not.
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Moreover, it seems soft link doesn't work

root@prod_ora08  # ln -s /usr/local/etc/sudoers /etc/sudoers
root@prod_ora08 # ls -l /etc/sudoers
lrwxrwxrwx   1 root     root          22 Jun 10 16:03 /etc/sudoers -> /usr/local/etc/sudoers
root@prod_ora08 # sudo
sudo: /etc/sudoers is not a regular file
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin
Jun 10 16:04:35 prod_ora08  sudo: [ID 702911 auth.alert]     root : /etc/sudoers is not a regular file ; TTY=pts/1 ; PWD=/root ;
root@prod_ora08  #

You shouldn't mess with sudo which is used by the OS and assumes its configuration file is in /etc and in particular might use the /etc/sudoers.d/svc-system-config-user file depending on the installation method.

What's wrong with in2nix4life's suggestion ?

#include /usr/local/etc/sudoers

Link doesn't works. in2nix4life's suggestion worked for me. Thanks