# 9.4. nginx as a Reverse Proxy

CouchDB recommends the use of HAProxy as a load balancer and reverse proxy. The team’s experience with using it in production has shown it to be superior for configuration and montioring capabilities, as well as overall performance.

CouchDB’s sample haproxy configuration is present in the code repository and release tarball as `rel/haproxy.cfg`.

However, `nginx` is a suitable alternative. Below are instructions on configuring nginx appropriately.

## 9.4.1. Basic configuration

Here’s a basic excerpt from an nginx config file in `<nginx config directory>/sites-available/default`. This will proxy all requests from `http://domain.com/...` to `http://localhost:5984/...`

    location / {
        proxy_pass http://localhost:5984;
        proxy_redirect off;
        proxy_buffering off;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

Proxy buffering must be disabled, or continuous replication will not function correctly behind nginx.

## 9.4.2. Reverse proxying CouchDB in a subdirectory with nginx

It can be useful to provide CouchDB as a subdirectory of your overall domain, especially to avoid CORS concerns. Here’s an excerpt of a basic nginx configuration that proxies the URL `http://domain.com/couchdb` to `http://localhost:5984` so that requests appended to the subdirectory, such as `http://domain.com/couchdb/db1/doc1` are proxied to `http://localhost:5984/db1/doc1`.

    location /couchdb {
        rewrite /couchdb/(.*) /$1 break;
        proxy_pass http://localhost:5984;
        proxy_redirect off;
        proxy_buffering off;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

Note that in the above configuration, the Verify Installation link in Fauxton may not succeed.

## 9.4.3. Authentication with nginx as a reverse proxy

Here’s a sample config setting with basic authentication enabled, placing CouchDB in the `/couchdb` subdirectory:

    location /couchdb {
        auth_basic "Restricted";
        auth_basic_user_file htpasswd;
        rewrite /couchdb/(.*) /$1 break;
        proxy_pass http://localhost:5984;
        proxy_redirect off;
        proxy_buffering off;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Authorization "";
    }

This setup leans entirely on nginx performing authorization, and forwarding requests to CouchDB with no authentication (with CouchDB in Admin Party mode). For a better solution, see Proxy Authentication.

## 9.4.4. SSL with nginx

In order to enable SSL, just enable the nginx SSL module, and add another proxy header:

    ssl on;
    ssl_certificate PATH_TO_YOUR_PUBLIC_KEY.pem;
    ssl_certificate_key PATH_TO_YOUR_PRIVATE_KEY.key;
    ssl_protocols SSLv3;
    ssl_session_cache shared:SSL:1m;

    location / {
        proxy_pass http://localhost:5984;
        proxy_redirect off;
        proxy_set_header Host $host;
        proxy_buffering off;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Ssl on;
    }

The `X-Forwarded-Ssl` header tells CouchDB that it should use the `https` scheme instead of the `http` scheme. Otherwise, all CouchDB-generated redirects will fail.