Monitoring Agent Overview

The 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 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 application metrics to Monitoring as custom metrics, see Monitoring Custom Applications.

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. Do not attempt to manually install or configure Monitoring agents 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 provides an option to install two versions of Stackdriver support on clusters and nodes. The option is presented when creating or updating clusters using either the GKE console or using the gcloud containers command. For more information, see:

Operating systems

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

  • Amazon Linux AMI
  • CentOS 7 and 6
  • Debian 9 "Stretch", Debian 8 "Jessie", Debian 7 "Wheezy", and Debian-7-backports
  • Red Hat Enterprise Linux 7 and 6
  • Ubuntu LTS 12.04 "Precise", LTS 14.04 "Trusty", LTS 16.04 "Xenial" (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, and 2016

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. For more information, see Monitoring Third-party Applications.

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.

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 Google Compute Engine or Amazon EC2 VM instances.
Was this page helpful? Let us know how we did:

Send feedback about...

Stackdriver Monitoring