Sometimes you need to place a site into maintenance mode for some reason. This is the easy way to do it.
1. Create a directory named err/ in the root directory. Lets say the site is called example.com.
cd /var/www/html/example.com mkdir err
2. Create a file named 503.html in the err directory.
cd /var/www/html/example.com/err touch 503.html
3. Put a maintenance message into 503.html.
echo "<html><b>This site is currently under maintenance. Thank you</b></html>" > 503.html
4. Add below lines to your virtual host setting for example.com.
ErrorDocument 503 /err/503.html ## uncomment below to enter maintenance mode RedirectMatch 503 ^/(?!err/)
5. Restart Apache.
httpd -k graceful
6. Test the website.