set nginx as proxy for both apache and gunicorn at the same time

Yes, this is possible. You'll need to configure Apache to listen on a different port though.

Don't select a reserved port and ensure that it's open (and that you can access it. Unix has a port range, usually defined in /proc/sys/net/ipv4/ip_local_port_range if you chose ipv4, which you probably have judging by your Nginx config)

For Apache configuration:

Edit you apache main configuration file and set the Listen directive as follows:

Listen 127.0.0.1:<port number that's open> //Use 8080 as port for a start

Then create a VirtualHost as follows:

<VirtualHost 127.0.0.1:<port number defined above>>    config goes here</VirtualHost>

You can do this in 2 ways, one from the same domain and one from a subdomain.

For NGINX configuration:

From the same domain:

server {    listen   80;    server_name XXXXX.com;#Django app served using Gunicorn    location / {        proxy_pass_header Server;        proxy_set_header Host $http_host;        proxy_redirect off;        proxy_set_header X-Real-IP $remote_addr;        proxy_set_header X-Scheme $scheme;        proxy_connect_timeout 120;        proxy_read_timeout 120;        proxy_pass http://localhost:8000/;    }#PHP processed by Apache    location ~ \.php$ {        proxy_pass_header Server;        proxy_set_header Host $http_host;        proxy_redirect off;        proxy_set_header X-Real-IP $remote_addr;        proxy_set_header X-Scheme $scheme;        proxy_connect_timeout 120;        proxy_read_timeout 120;        proxy_pass http://localhost:<port you configured apache to listen on>/;    }}

From a subdomain:

#Server block for Django server {    listen   80;    server_name XXXXX.com;    location / {        proxy_pass_header Server;        proxy_set_header Host $http_host;        proxy_redirect off;        proxy_set_header X-Real-IP $remote_addr;        proxy_set_header X-Scheme $scheme;        proxy_connect_timeout 120;        proxy_read_timeout 120;        proxy_pass http://localhost:8000/;    }}#Server block for PHP served using Apache with a subdomainserver {    listen   80;    server_name blog.XXXXX.com;    location / {        proxy_pass_header Server;        proxy_set_header Host $http_host;        proxy_redirect off;        proxy_set_header X-Real-IP $remote_addr;        proxy_set_header X-Scheme $scheme;        proxy_connect_timeout 120;        proxy_read_timeout 120;        proxy_pass http://localhost:<port you configured apache to listen on>/;    }}

Note: You don't need the root directive because your applications are being served by either Gunicorn or being handed over to Apache (where you'll define a root in the VirtualHost)

Once you've edited your config files, restart Apache and then restart Nginx, it should work.