# NGINX check

![NGINX default dashboard][1]

## Overview

The Datadog Agent can collect many metrics from NGINX instances, including (but not limited to)::

- Total requests
- Connections (e.g. accepted, handled, active)

For users of NGINX Plus, the commercial version of NGINX, the Agent can collect the significantly more metrics that NGINX Plus provides, like:

- Errors (e.g. 4xx codes, 5xx codes)
- Upstream servers (e.g. active connections, 5xx codes, health checks, etc.)
- Caches (e.g. size, hits, misses, etc.)
- SSL (e.g. handshakes, failed handshakes, etc.)

## Setup

### Installation

The NGINX check pulls metrics from a local NGINX status endpoint, so your `nginx` binaries need to have been compiled with one of two NGINX status modules:

- [stub status module][2] - for open source NGINX
- [http status module][3] - only for NGINX Plus

#### NGINX Open Source

If you use open source NGINX, your instances may lack the stub status module. Verify that your `nginx` binary includes the module before proceeding to **Configuration**:

```shell
$ nginx -V 2>&1| grep -o http_stub_status_module
http_stub_status_module
```

If the command output does not include `http_stub_status_module`, you must install an NGINX package that includes the module. You _can_ compile your own NGINX-enabling the module as you compile it-but most modern Linux distributions provide alternative NGINX packages with various combinations of extra modules built in. Check your operating system's NGINX packages to find one that includes the stub status module.

#### NGINX Plus

NGINX Plus packages prior to release 13 include the http status module. For NGINX Plus release 13 and above, the status module is deprecated and you must use the new Plus API instead. See [the announcement][4] for more information.

#### Prepare NGINX

On each NGINX server, create a `status.conf` file in the directory that contains your other NGINX configuration files (e.g. `/etc/nginx/conf.d/`).

```conf
server {
  listen 81;
  server_name localhost;

  access_log off;
  allow 127.0.0.1;
  deny all;

  location /nginx_status {
    # Choose your status module

    # freely available with open source NGINX
    stub_status;

    # for open source NGINX < version 1.7.5
    # stub_status on;

    # available only with NGINX Plus
    # status;

    # ensures the version information can be retrieved
    server_tokens on;
  }
}
```

**NGINX Plus**

NGINX Plus users can also utilize `stub_status`, but since that module provides fewer metrics, Datadog recommends using `status`.

For NGINX Plus releases 15+, the `status` module is deprecated. Use the [http_api_module][5] instead. For example, enable the `/api` endpoint in your main NGINX configuration file (`/etc/nginx/conf.d/default.conf`):

```conf
server {
  listen 8080;
  location /api {
    api write=on;
  }
}
```

To get more detailed metrics with NGINX Plus (such as 2xx / 3xx / 4xx / 5xx response counts per second), set a `status_zone` on the servers you want to monitor. For example:

```conf
server {
  listen 80;
  status_zone <ZONE_NAME>;
  ...
}
```

Reload NGINX to enable the status or API endpoint. There's no need for a full restart.

```shell
sudo nginx -t && sudo nginx -s reload
```

### Configuration

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#### Host

To configure this check for an Agent running on a host:

Follow the instructions below to configure this check for an Agent running on a host. For containerized environments, see the [Containerized section](#containerized).

##### Metric collection

1. Set the `nginx_status_url` parameter to `http://localhost:81/nginx_status/` in your `nginx.d/conf.yaml` file to start gathering your [NGINX metrics](#metrics). See the [sample nginx.d/conf.yaml][6] for all available configuration options.

    **NGINX Plus**:

      - For NGINX Plus releases 13+, set the parameter `use_plus_api` to `true` in your `nginx.d/conf.yaml` configuration file.
      - Stream stats API calls are included by default for NGINX Plus. If you want to disable them, set the parameter `use_plus_api_stream` to `false` in your `nginx.d/conf.yaml` configuration file.
      - If you are using `http_api_module`, set the parameter `nginx_status_url` to the server's `/api` location in your `nginx.d/conf.yaml` configuration file, for example:

          ```yaml
          nginx_status_url: http://localhost:8080/api
          ```

2. Optional - If you are using the NGINX `vhost_traffic_status module`, set the parameter `use_vts` to `true` in your `nginx.d/conf.yaml` configuration file.

3. [Restart the Agent][7] to start sending NGINX metrics to Datadog.

##### Log collection

_Available for Agent versions >6.0_

1. Collecting logs is disabled by default in the Datadog Agent, enable it in your `datadog.yaml` file:

   ```yaml
   logs_enabled: true
   ```

2. Add this configuration block to your `nginx.d/conf.yaml` file to start collecting your NGINX Logs:

   ```yaml
   logs:
     - type: file
       path: /var/log/nginx/access.log
       service: nginx
       source: nginx

     - type: file
       path: /var/log/nginx/error.log
       service: nginx
       source: nginx
   ```

    Change the `service` and `path` parameter values and configure them for your environment. See the [sample nginx.d/conf.yaml][6] for all available configuration options.

3. [Restart the Agent][7].

**Note**: The default NGINX log format does not have a request response time. To include it into your logs, update the NGINX log format by adding the following configuration block in the `http` section of your NGINX configuration file (`/etc/nginx/nginx.conf`):

```conf
http {
	#recommended log format
	log_format nginx '\$remote_addr - \$remote_user [\$time_local] '
                  '"\$request" \$status \$body_bytes_sent \$request_time '
                  '"\$http_referer" "\$http_user_agent"';

	access_log /var/log/nginx/access.log;
}
```

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#### Containerized

For containerized environments, see the [Autodiscovery Integration Templates][8] for guidance on applying the parameters below.

##### Metric collection

| Parameter            | Value                                                      |
| -------------------- | ---------------------------------------------------------- |
| `<INTEGRATION_NAME>` | `nginx`                                                    |
| `<INIT_CONFIG>`      | blank or `{}`                                              |
| `<INSTANCE_CONFIG>`  | `{"nginx_status_url": "http://%%host%%:81/nginx_status/"}` |

**Note**: This `<INSTANCE_CONFIG>` configuration works only with NGINX Open Source. If you are using NGINX Plus, inline the corresponding instance configuration.

##### Log collection

_Available for Agent versions >6.0_

Collecting logs is disabled by default in the Datadog Agent. To enable it, see [Kubernetes log collection documentation][9].

| Parameter      | Value                                     |
| -------------- | ----------------------------------------- |
| `<LOG_CONFIG>` | `{"source": "nginx", "service": "nginx"}` |

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### Validation

[Run the Agent's status subcommand][10] and look for `nginx` under the Checks section.

## Data Collected

### Metrics

See [metadata.csv][11] for a full list of provided metrics by this integration.

Not all metrics shown are available to users of open source NGINX. Compare the module reference for [stub status][2] (open source NGINX) and [http status][3] (NGINX Plus) to understand which metrics are provided by each module.

A few open-source NGINX metrics are named differently in NGINX Plus; they refer to the exact same metric, though:

| NGINX                          | NGINX Plus                   |
| ------------------------------ | ---------------------------- |
| `nginx.net.connections`        | `nginx.connections.active`   |
| `nginx.net.conn_opened_per_s`  | `nginx.connections.accepted` |
| `nginx.net.conn_dropped_per_s` | `nginx.connections.dropped`  |
| `nginx.net.request_per_s`      | `nginx.requests.total`       |

These metrics don't refer exactly to the same metric, but they are somewhat related:

| NGINX               | NGINX Plus               |
| ------------------- | ------------------------ |
| `nginx.net.waiting` | `nginx.connections.idle` |

Finally, these metrics have no good equivalent:

| Metric              | Description                                                                               |
| ------------------- | ----------------------------------------------------------------------------------------- |
| `nginx.net.reading` | The current number of connections where nginx is reading the request header.              |
| `nginx.net.writing` | The current number of connections where nginx is writing the response back to the client. |

### Events

The NGINX check does not include any events.

### Service Checks

**nginx.can_connect**:<br>
Returns `CRITICAL` if the Agent cannot connect to NGINX to collect metrics, otherwise returns `OK`.

## Troubleshooting

- [Why do my logs not have the expected timestamp?][12]

Need help? Contact [Datadog support][13].

## Further Reading

Additional helpful documentation, links, and articles:

- [How to monitor NGINX][14]
- [How to collect NGINX metrics][15]
- [How to monitor NGINX with Datadog][16]

[1]: https://raw.githubusercontent.com/DataDog/integrations-core/master/nginx/images/nginx_dashboard.png
[2]: https://nginx.org/en/docs/http/ngx_http_stub_status_module.html
[3]: https://nginx.org/en/docs/http/ngx_http_status_module.html
[4]: https://www.nginx.com/blog/nginx-plus-r13-released
[5]: https://nginx.org/en/docs/http/ngx_http_api_module.html
[6]: https://github.com/DataDog/integrations-core/blob/master/nginx/datadog_checks/nginx/data/conf.yaml.example
[7]: https://docs.datadoghq.com/agent/guide/agent-commands/#start-stop-and-restart-the-agent
[8]: https://docs.datadoghq.com/agent/kubernetes/integrations/
[9]: https://docs.datadoghq.com/agent/kubernetes/log/
[10]: https://docs.datadoghq.com/agent/guide/agent-commands/#agent-status-and-information
[11]: https://github.com/DataDog/integrations-core/blob/master/nginx/metadata.csv
[12]: https://docs.datadoghq.com/logs/faq/why-do-my-logs-not-have-the-expected-timestamp/
[13]: https://docs.datadoghq.com/help/
[14]: https://www.datadoghq.com/blog/how-to-monitor-nginx
[15]: https://www.datadoghq.com/blog/how-to-collect-nginx-metrics/index.html
[16]: https://www.datadoghq.com/blog/how-to-monitor-nginx-with-datadog/index.html
