Monitoring agent overview

The Stackdriver Monitoring agent is a collectd-based daemon that gathers system and application metrics from virtual machine instances and sends them to Monitoring. By default, the Monitoring agent collects disk, CPU, network, and process metrics. You can configure the Monitoring agent to monitor third-party applications to get the full list of agent metrics.

To install the Monitoring agent, see Installing the Monitoring agent.


Using the Monitoring agent is optional but recommended. Monitoring can access some instance metrics without the Monitoring agent, including CPU utilization, some disk traffic metrics, network traffic, and uptime information. Monitoring uses the Monitoring agent to access additional system resources and application services in virtual machine (VM) instances. If you want these additional capabilities, you should install the Monitoring agent.

After installing the Monitoring agent, you can monitor supported third-party applications by adding application-specific collectd configurations. See Monitoring third-party applications for details.

For a complete list of the built-in metrics you can get with the Monitoring agent, see Agent metrics.

To send any custom metric to Monitoring using the agent, see Monitoring custom applications. If you have access to the source code of your application, it may be more convenient to instrument it with OpenCensus.

Supported configurations

The Monitoring agent is compatible with the following environments.

Virtual machine instances

You can install the Monitoring agent on the following kinds of VM instances:

The following types of VM instances use special Monitoring support. Don't try to manually install or configure the Monitoring agent on them:

  • App Engine standard has built-in Monitoring support. Agents are not needed.

  • App Engine flexible environment has pre-installed agents with special configurations.

  • Google Kubernetes Engine node instances. You can enable Stackdriver Kubernetes Engine Monitoring, an integrated monitoring and logging solution, for your new or existing container clusters.

  • For instances running on GKE On-Prem, the agent collects system metrics but doesn't collect application metrics.

Operating systems

The Monitoring agent supports the following operating systems on compatible VM instances:

  • Amazon Linux AMI
  • CentOS 6, 7, and 8
  • Debian 9 "Stretch"
  • Red Hat Enterprise Linux 6, 7, and 8
  • Ubuntu LTS 16.04 "Xenial", LTS 18.04 "Bionic" (only LTS releases are supported)
  • Ubuntu Minimal LTS 16.04 "Xenial", LTS 18.04 "Bionic" (only LTS releases are supported)
  • SUSE Linux Enterprise Server 12 SP3, 12 SP2 for SAP, and 12 SP3 for SAP
  • Microsoft Windows Server 2008, 2012, 2016, and 2019

The Monitoring agent does not presently support the Container-Optimized OS that is the default in Kubernetes Engine clusters.

Supported applications

You can configure Monitoring to monitor a variety of popular open source software applications. Configuration is only possible for agents running on Linux. Agents running on Windows can monitor IIS and MS SQL applications, but they are not configurable for other applications.

For more information, see Monitoring third-party applications.

Agent access requirements

Running the agent requires access to the following DNS names:

  • OAuth2 token server: (full URL:

  • Monitoring APIs:

Installing the agent requires access to the following DNS names:

  • (Linux) Google Cloud package repository:

  • (Windows) Google download server:

Getting the Monitoring agent source code

The source code for the Monitoring agent is available for only the Linux-hosted Monitoring agent. The Windows-hosted Monitoring agent is not open source.

The Monitoring agent is installed by a script described in the installation instructions. You do not need the information in this section unless you want to understand the source code or you have other special needs.

The Monitoring agent, stackdriver-agent, is based on the original collectd system statistics collection daemon. stackdriver-agent source code is available at Stackdriver/collectd. The build and packaging scripts for the Monitoring agent are available at Stackdriver/agent-packaging. The configuration files for third-party applications are in the agent's GitHub configuration repository.

The software package for stackdriver-agent contains:

  • The collectd daemon.
  • The plugin shared libraries, including the Stackdriver Monitoring API output plugin.
  • The top-level configuration files for the Monitoring agent.

Deprecation policy

The Monitoring agent is subject to the Stackdriver agents deprecation policy.

What's next

  • See Quickstart to monitor a VM instance running an Apache web server. The quickstart includes installing the agent.
  • See Installing monitoring agents to install the agent on Compute Engine or Amazon EC2 VM instances.