Host Agent

Instana collects data from monitored systems using a single agent on each host. The agent runs on your hosts to collect and aggregate data from various sensors before sending it to the Instana backend.

Host Agent Types

The Instana Host Agent comes in two flavors, dynamic and static, based on whether it can update itself or not.

  • A dynamic host agent downloads on startup the latest set of sensors from repositories; also, by default a dynamic agent will updates itself on a daily basis with the latest and greatest capabilities released. It is also possible to tightly control the updating of dynamic host agents by pinning a version. The dynamic host agent is preferred in most scenarios for its ease of use and the quick turn-around in acquiring new capabilities, performance improvements and bug-fixes. By default, dynamic host agents will use the Instana repository to pull updates, but in very advanced use-cases it is possible to set up your own managed mirror. See the Host Agent Updates documentation for more information on how host agent updates can be configured.
  • A static host agent is a self-contained host agent that includes all the latest available components at the time of its release and that has no dynamic update capabilities. One the one hand, the static host agent has a stable "bill of materials", that never changes after the host agent's installation. On the other hand, the lack of update capabilities means that you will need to provide your own way of keeping Instana agents up-to-date using, for example, infrastructure-as-code tools like Ansible or Terraform. Static host agents require no internet connection to the Instana repository, and are recommended in restrictive network setups.

In general, we strongly recommend to use dynamic agents whenever possible: we see that static agents tend to get updated very infrequently, and that makes you miss out on new capabilities, performance improvements and bug-fixes.

Host Agent Modes

The Instana host agent has different modes of operation, in which it will monitor its host and the applications running on it to different extents:

  • OFF mode means that the host agent will not perform any monitoring, but just notify at regular intervals the Instana backend that it is running idle.
  • INFRASTRUCTURE mode means that the host agent will monitor the underpinning host and will activate its sensors for every technology supported by Instana, but it will not perform any tracing of applications.
  • APM mode (the default) means that the host agent offers the full Instana experience, monitoring and tracing every technology it knows how.

Note: The One-Liner host agent installation method and the Instana Host Agent Docker image accept an additional mode, called AWS mode. The AWS mode of the host agent is not meant for monitoring hosts; rather, it is simply the INFRASTRUCTURE mode plus some automatic configuration of AWS data collection, as described in our AWS Agent documentation.

Note: Host agent modes can be changed after the host agent installation using the Agent Management Dashboard; for more information, refer to the Set the Host Agent Mode documentation.