Multi-Website Setup On Magento2 By Nginx

go the the directory = cd /etc/nginx/sites-available

      create a file i.e   = sudo nano local   (paste the below data - here i am doing two site setup)
 #-------------------------------------------------------------------> 
       upstream fastcgi_backend {
             server unix:/run/php/php8.1-fpm.sock;
        }

        map $http_host $MAGE_RUN_CODE {
            default '';
            dev.forevernew.co.nz fn_nz;
            dev.forevernew.co.au fn_au;
        }

        server {
            listen 80;
            server_name dev.local.co.nz dev.local.co.nz dev.local.co.au;
            set $MAGE_ROOT /var/www/html/local;
            set $MAGE_MODE developer;
            set $MAGE_RUN_TYPE website; #or set $MAGE_RUN_TYPE store;
            include /var/www/html/local/nginx.conf.sample;
        }
  #-------------------------------------------------------------------> 

        get the website code from this magento table i.e = store_website    (get the Code column value )[here fn_nz and fn_au are  website code ]

Step -2

 create two more file inside this  {" cd /etc/nginx/sites-available " directory}  [two store so - two file create if more create more file]

      i)  sudo nano dev.local.co.nz  (paste the below data)

           server {
                listen 80;
                server_name dev.local.co.nz;
                set $MAGE_ROOT /var/www/html/local;
                set $MAGE_MODE developer;
                set $MAGE_RUN_TYPE website; #or set $MAGE_RUN_TYPE store;
                set $MAGE_RUN_CODE fn_nz;
                include /var/www/html/local/nginx.conf.sample;
             }


     ii) sudo nano dev.forevernew.co.au  (paste the below data)

            server {
                listen 80;
                server_name dev.local.co.au;
                set $MAGE_ROOT /var/www/html/local;
                set $MAGE_MODE developer;
                set $MAGE_RUN_TYPE website; #or set $MAGE_RUN_TYPE store;
                set $MAGE_RUN_CODE fn_au;
                include /var/www/html/local/nginx.conf.sample;
            }

Step -3

- create the all 3- files symlink to cd /etc/nginx/sites-enabled

         - sudo ln -s /etc/nginx/sites-available/local /etc/nginx/sites-enabled
         - sudo ln -s /etc/nginx/sites-available/dev.local.co.nz /etc/nginx/sites-enabled
         - sudo ln -s /etc/nginx/sites-available/dev.local.co.au /etc/nginx/sites-enabled

         - sudo nginx -t

         - sudo service nginx restart

Step -4

 - Go the your magento folder location (e.g = /var/www/html/local )

         - Find nginx.conf.sample  file 

         - Edit --->  nginx.conf.sample  

         - Search   below location 

             Previous (existing)
             =====================
                # PHP entry point for main application
                    location ~ (index|get|static|report|404|503|health_check)\.php$ {
                        try_files $uri =404;
                        fastcgi_pass   fastcgi_backend;
                        fastcgi_buffers 1024 4k;

                        fastcgi_param  PHP_FLAG  "session.auto_start=off \n suhosin.session.cryptua=off";
                        fastcgi_param  PHP_VALUE "memory_limit=1G \n max_execution_time=18000";
                        fastcgi_read_timeout 600s;
                        fastcgi_connect_timeout 600s;

                        fastcgi_index  index.php;
                        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
                        include        fastcgi_params;
                    }

Step -5

  - Modify the above with Below Two Line  (Before " include    fastcgi_params;  Line)
        #------------------------------------------------------------------->   
                - fastcgi_param MAGE_RUN_TYPE $MAGE_RUN_TYPE;
                - fastcgi_param MAGE_RUN_CODE $MAGE_RUN_CODE;
        #------------------------------------------------------------------->

Step -6

After Modify (currently)
            ========================
            # PHP entry point for main application

                location ~ (index|get|static|report|404|503|health_check)\.php$ {
                    try_files $uri =404;
                    fastcgi_pass   fastcgi_backend;
                    fastcgi_buffers 1024 4k;

                    fastcgi_param  PHP_FLAG  "session.auto_start=off \n suhosin.session.cryptua=off";
                    fastcgi_param  PHP_VALUE "memory_limit=1G \n max_execution_time=18000";
                    fastcgi_read_timeout 600s;
                    fastcgi_connect_timeout 600s;

                    fastcgi_index  index.php;
                    fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
            #------------------------------------------------------------------->        
                    # START - Multisite customization
                    fastcgi_param MAGE_RUN_TYPE $MAGE_RUN_TYPE;
                    fastcgi_param MAGE_RUN_CODE $MAGE_RUN_CODE;
                    # END - Multisite customization
            #-------------------------------------------------------------------->
                    include        fastcgi_params;
                }