Maintenance page on nginx, best practices

Question

I want to configure the server to show a maintenance page when it exist. I tried this code and works:

location / {
    try_files /maintenance.html $uri $uri/ @codeigniter;
}

But I noticed it would be served with a 200 status code, and it can cause confusion to search engines. I think the best practice would be returning a 503 status code. On google I find several relevant pages about it, like this. However, they use if to make the redirect and according to nginx documentation it isn't safe to use ifs.

Is there a way of doing it without using if? Is safe to use if in this case?

Thanks.

Answer 1

Here is what I do.

            if (-f $document_root/maintenance.html) {
                    return 503;
            }
            error_page 503 @maintenance;
            location @maintenance {
                    rewrite ^(.*)$ /maintenance.html break;
            }

If the file is there it will show the maintenance page. Once you remove the file you will go back to normal.

Answer 2

I think the best practice would be returning a 500 status code.

I think you mean 503 instead of 500.

they use if to make the redirect and according to nginx documentation it isn't safe to use ifs.

No. Only return is 100% safe inside if in location context.

According to nginx documentation, you can specify an HTTP status code as the last argument to try_files. I've tried this but it didn't work.

Answer 3

If the maintenance page only has HTML

No asset file (CSS, JS, ...)

location = @maintenance {
    root html/;
    # `break`: use this `location` block
    rewrite ^ "/maintenance.html" break;
}

location / {
    error_page 503 @maintenance;
    return 503;

    # ...
}

For maintenance page that has asset file (CSS / JS / ...)

The flow of this is:

• If URI is /, return 503
  • Internal redirect to /maintenance.html
• If URI found in maintenance directory (for asset), return file with status 200
• All other request, redirect to /

# for handle maintenance web page
server {
    listen unix:/var/run/maintenance.nginx.sock;

    # for Windows
    # listen 8000;
    
    location @index {
        # use redirect because if URI has sub-folder ($uri == /path/path/),
        # the relative path for asset file (CSS, JS, ...) will be incorrect
        rewrite ^ / redirect;
    }

    location = / {
        # maintenance page URI
        error_page 503 /maintenance.html;

        return 503;
    }

    # use RegExp because it has higher priority
    location / {
        root html/maintenance/;

        # redirect all URI to index (503) page (except asset URI),
        # asset URI still return status 200
        try_files $uri @index;
    }
}

# original server block
server {
    listen 80;
    location / {
        proxy_pass http://unix:/var/run/maintenance.nginx.sock:;

        # for Windows
        # proxy_pass http://127.0.0.1:8000;
    }

    # ...
}

• You can put the config in a maintenance.conf, include maintenance.conf when in maintenance.

• I will not use if (-f <file>) because it will try to check if the file exist on every request

If you need bypass some IP address

More detail here

Ref: Nginx Maintenance

Answer 4

This config works for me:

server {
  server_name _;
  listen 443 ssl http2;
  listen [::]:443 ssl http2;
  location ~* \.(css|png|js|jpg|jpeg|ico) {
      root /static/maintenance;
  }
  error_page 503 @maintenance;
  location @maintenance {
    root /static/maintenance;
    rewrite ^(.*)$ /index.html break;
  }
  location / {
    return 503;
  }
}

It returns /static/maintenance/index.html file with code 503 for every request.

It doesn't change URL with redirections.

Resources like

• /static/maintenance/main.css,
• /static/maintenance/favicon.ico,
• etc.

are available with code 200.