one IP: virtual machines for virtual hosts? [closed]

Question

I currently have one hardware linux server with one IP address that is running three websites (virtualhosts via apache). I would like to push each website into its own virtual machine in order to improve isolation/security, and for easier migration to different hardware if the need ever arises. (I am beginning to check into coreos for this purpose.)

but I am baffled by the easy question. how do I push different virtualhost httpd (or ssh or ...) requests to different virtual machines on the same IP hardware?? this is not a DNS-level question---my DNS provider only pushes my visitors to the main IP, me thinks.

advice appreciated.

regards,

/iaw

Answer 1

You can set up a proxy server that redirects traffic to the virtual server based on the vhost rules. Apache has mod_proxy for this, you can setup a reverse proxy/gateway that redirects HTTP traffic to the right virtual machine based on the vhost matching.

Answer 2

You need a reverse proxy seating on the host machine. there are several good ones. Apache with mod_proxy for example:

<VirtualHost external_IP:80>
 ServerName cust1.dev.domain.com
 ServerAdmin [email protected]
 ProxyRequests off
 ProxyPreserveHost on
 ProxyPass / http://192.168.0.100/
 ProxyPassReverse / http://192.168.0.100/
 <Proxy *>
      Order allow,deny
      Allow from all
 </Proxy>
 ErrorLog /var/log/apache2/cust1.dev.domain.com.log
 CustomLog /var/log/apache2/cust1.dev.domain.com.err.log combined
</VirtualHost>

<VirtualHost external_IP:80>
     ServerName cust2.dev.domain.com
     ServerAdmin [email protected]
     ProxyRequests off
     ProxyPreserveHost on
     ProxyPass / http://192.168.0.101/
     ProxyPassReverse / http://192.168.0.101/
     <Proxy *>
          Order allow,deny
          Allow from all
     </Proxy>
     ErrorLog /var/log/apache2/cust2.dev.domain.com.log
     CustomLog /var/log/apache2/cust2.dev.domain.com.err.log combined
</VirtualHost>

Or you could do it with nginx:

upstream vm1  {
      server 192.168.1.100:80; #VM1
}

upstream vm2  {
      server 192.168.1.101:80; #VM2
}

## Start VM1 ##
server {
    listen       external_IP:80;
    server_name  www.example.com;

    access_log  /var/log/nginx/log/www.example.access.log  main;
    error_log  /var/log/nginx/log/www.example.error.log;
    root   /usr/share/nginx/html;
    index  index.html index.htm;

    ## send request back to apache1 ##
    location / {
     proxy_pass  http://vm1;
     proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
     proxy_redirect off;
     proxy_buffering off;
     proxy_set_header        Host            $host;
     proxy_set_header        X-Real-IP       $remote_addr;
     proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
   }
}

## START VM2 ##
server {
   listen      external_IP:80;
   server_name static.example.com;
   access_log  /var/log/nginx/log/static.example.com.access.log  main;
   error_log   /var/log/nginx/log/static.example.com.error.log;
   root        /usr/local/nginx/html;
   index       index.html;

   location / {
        proxy_pass  http://vm2;
        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
        proxy_redirect off;
        proxy_buffering off;
        proxy_set_header        Host            static.example.com;
        proxy_set_header        X-Real-IP       $remote_addr;
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

Answer 3

Different hosts need to have dIfferent IP addresses. You may be able to hack something together with NAT and a proxy server for the websites. SSH would have to be on different ports for each server.

You are far better off assigning proper IP addresses to each server. Hosting websites on seperate servers is a valid justification for requesting more IP addresses.