Basic Agent Usage

Agent v6 and v7 are composed of a main process responsible for collecting infrastructure metrics, logs, and receiving DogStatsD metrics. The main components to this process are:

• The Collector is in charge of running checks and collecting metrics.
• The Forwarder sends payloads to Datadog.

Two optional processes are spawned by the Agent if enabled in the datadog.yaml configuration file:

• The APM Agent is a process to collect traces (enabled by default).
• The Process Agent is a process to collect live process information. By default, it only collects available containers, otherwise it is disabled.

On Windows the services are listed as:

By default the Agent binds 3 ports on Linux and 4 on Windows and OSX:

For information on configuring the ports, see Network Traffic.

Collector

The collector gathers all standard metrics every 15 seconds. Agent v6 embeds a Python 2.7 interpreter to run integrations and custom checks.

Forwarder

The Agent forwarder send metrics over HTTPS to Datadog. Buffering prevents network splits from affecting metric reporting. Metrics are buffered in memory until a limit in size or number of outstanding send requests are reached. Afterwards, the oldest metrics are discarded to keep the forwarder’s memory footprint manageable. Logs are sent over an SSL-encrypted TCP connection to Datadog.

DogStatsD

In v6, DogStatsD is a Golang implementation of Etsy’s StatsD metric aggregation daemon. It is used to receive and roll up arbitrary metrics over UDP or Unix socket, thus allowing custom code to be instrumented without adding latency. Learn more about DogStatsD.

Agent v5 is composed of four major components, each written in Python running as a separate process:

• Collector (agent.py): The collector runs checks on the current machine for configured integrations, and captures system metrics, such as memory and CPU.
• DogStatsD (dogstatsd.py): This is a StatsD-compatible backend server that you can send custom metrics to from your applications.
• Forwarder (ddagent.py): The forwarder retrieves data from both DogStatsD and the collector, queues it up, and then sends it to Datadog.
• SupervisorD: This is all controlled by a single supervisor process. It is kept separate to limit the overhead of each application if you aren’t running all parts. However, it is generally recommended to run all parts.

Note: For Windows users, all four Agent processes appear as instances of ddagent.exe with the description DevOps' best friend.

Supervision, privileges, and network ports

A SupervisorD primary process runs as the dd-agent user, and all forked subprocesses run as the same user. This also applies to any system call (iostat/netstat) initiated by the Datadog Agent. The Agent configuration resides at /etc/dd-agent/datadog.conf and /etc/dd-agent/conf.d. All configuration must be readable by dd-agent. The recommended permissions are 0600 since configuration files contain your API key and other credentials needed to access metrics.

The following ports are open for operations:

All listening processes are bound by default to 127.0.0.1 and/or ::1 on v3.4.1+ of the Agent. In earlier versions, they were bound to 0.0.0.0 (all interfaces). For information on running the Agent through a proxy see Agent proxy configuration. For information on IP ranges to allow, see Network Traffic.

The recommended number of open file descriptors is 1024. You can see this value with the command ulimit -a. If you have a hard limitation below the recommended value, for example Shell Fork Bomb Protection, one solution is to add the following in supervisord.conf:

[supervisord]
minfds = 100  # Your hard limit

• Agent Test version: 6.15.0
• CPU: ~ 1.5% of the CPU used on average
• Memory: ~ 95MB of RAM used.
• Network bandwidth: ~ 14 KB/s ▲

• Agent Test version: 6.15.0
• CPU: ~ 1% of the CPU used on average
• Memory: ~ 95MB of RAM used.
• Network bandwidth: ~ 20 KB/s ▲

• Agent Test version: 6.15.0
• CPU: ~ 0.7% of the CPU used on average
• Memory: ~ 90MB of RAM used (RSS memory)
• Network bandwidth: ~ 200 KB/s ▲