This is a legacy agent. While this agent is still supported on Linux,we recommend against using it for new Google Cloud workloads.

Instead, we recommend that you use theOps Agentfor new Google Cloud workloads and eventually transition your existingCompute Engine VMs to use the Ops Agent.The Ops Agent, which combines the collection of metrics and logging into asingle agent, is the eventual replacement for the legacy agents.

The Ops Agent is under active development, but there might be someuse cases that it doesn't support. If the Ops Agent doesn't support youruse case, then you can still use theMonitoring agent on Linux.

There will be no new feature development or support for new operating systemsfor the legacy Monitoring agent.

We strongly recommend against using the legacy Monitoring agent on Windows.The legacy Monitoring agent on Windows is unsupported, and all of its features are available in the Ops Agent. We strongly recommend using Ops Agent for monitoring Windows instances. However, if you have to run the legacy Logging agent on Windows and also need to collect metrics, you must use the legacy Monitoring agent; you can't run the Ops Agent and a legacy agent on the same machine.

Caution: The 5.x version of the Monitoring agent has beendeprecated and decommissioned. Forinformation about the latest agent versions, seeListing all agent versions.

The Monitoring agent is acollectd-based daemon that gatherssystem and application metrics from virtual machine instances and sends them toMonitoring. By default, the Monitoring agent collects disk, CPU,network, and process metrics. You can configure the Monitoring agent to monitorthird-party applications to get thefull list of agent metrics.

To install the agent, seeInstalling the Monitoring agent.

Note: If yourmetrics scope is configured with aVPC Service Controls Service Perimeter for the Monitoring API, then the Monitoring agent won't work onany virtual machine instance outside the perimeter. To learn more about Service Perimeters, seeService perimeter details and configuration.

Purpose

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

Note: The Monitoring agent is designed to ingest system, third-party,custom, and agent telemetry metrics. Some of these metrics are chargeable.For pricing information, seeGoogle Cloud Observability pricing.

After installing the Monitoring agent, you can monitor supportedthird-party applications by adding application-specificcollectdconfigurations. SeeMonitoring third-partyapplications for details.

For a complete list of the built-in metrics you can get with theMonitoring agent, seeAgent metrics.

To send any custom metric to Monitoring using the agent, seeMonitoring custom applications. If youhave access to the source code of your application, it may be more convenient toinstrument it with OpenTelemetry. For information about instrumentation, seeInstrumentation and observability.

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 VMinstances:

• Compute Engine instances. The Monitoring agentsends monitoring information to each instance's associated project.

  For instances without external IP addresses, you mustenable Private GoogleAccessto allow the Monitoring agent to send metrics.

  To create a Compute Engine instance, seeCompute Engine getting started guide.

Note:The Monitoring agent is not supported on on-premises machines.

The following types of VM instances belong to managed services that implementservice-specificMonitoringsupport. Don't try to manually install or configure the Monitoring agent on them:

• App Engine standard has built-in Monitoring support. Agents aren't needed.
• App Engine flexible environment instances have pre-installed agents with service-specific configurations.
• Dataflow instances have pre-installed Monitoring agents with service-specific configurations.

• Dataproc instances prior to image version 2.2 have pre-installed Monitoring agents with service-specific configurations.

  You can install the Ops Agent on Dataproc clusters that use image version 2.2 and later to collect syslog logs and host metrics. For more information, see Dataproc 2.2.x release versions.

• Google Kubernetes Engine node instances:
  • GKE on Google Cloud clusters are configured tocollect logs and metrics with Logging and Monitoring by default. You can also configure metric and log collection for existing container clusters. For information, seeConfiguring logging and monitoring for GKE.
  • Google Distributed Cloud instances have an integrated logging and monitoring solution that collects status about system components. For information, see Logging and monitoring.

Operating systems

The Monitoring agent supports the following operating systems oncompatible VM instances.

Linux operating systems

The Monitoring agent supports the following Linux operating systems:

• Rocky Linux 8
• RHEL 8: rhel-8-6-sap-ha, rhel-8-8-sap-ha
• SLES 12: sles-12-sp5-sap
• SLES 15: sles-15-sp5, sles-15-sp3-sap, sles-15-sp4-sap, sles-15-sp5-sap

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

Windows operating systems:

All versions of the Monitoring agent support the followingWindows operating systems:

• Windows Server 2019
• Windows Server Core 2019
• Windows Server 2016
• Windows Server Core 2016

The Monitoring agent does not presently support Windows ServerCore 2019 for containers.

Supported applications

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

For more information, seeMonitoring third-party applications.

Note: The interoperability of the agent and third-party plugins on SUSE Linuxhas not been tested. This is a known limitation.

Agent access requirements

Running the agent requires access to the following DNS names:

• OAuth2 token server:oauth2.googleapis.com

  Earlier versions of the agent may require access towww.googleapis.com(full URL:https://www.googleapis.com/oauth2/v3/token).

  If you're using an older version of the agent, it's recommended that youupgrade your agent tothe latest version.

• Monitoring APIs:monitoring.googleapis.com

Installing the agent requires access to the following DNS names:

• (Linux) Google Cloud package repository:packages.cloud.google.com

• (Linux) Google downloads subdomain:dl.google.com

• (Windows) Legacy Stackdriver download server:repo.stackdriver.com

Getting the Monitoring agent source code

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

The Monitoring agent is installed by a script described in theinstallation instructions.You can skip this section if you only want to install and use the agent. If youwant to understand the source code, then read this section.

The Monitoring agent,stackdriver-agent, is based on theoriginalcollectd systemstatistics collection daemon.stackdriver-agent source code is available atStackdriver/collectd.The build and packaging scripts for the Monitoring agent areavailable atStackdriver/agent-packaging.The configuration files for third-party applications are in the agent'sGitHub configuration repository.

The software package forstackdriver-agent contains:

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

Deprecation policy

The Monitoring agent is subject to theAgents deprecation policy.

For deprecation information for legacy features and versions, refer toGoogle Cloud Observability deprecations.

What's next

• SeeQuickstart to monitor a VM instancerunning an Apache web server. The quickstart includes installing the agent.