Instana agent types

Host agent types

The Instana host agents are of 2 types: dynamic and static, determined by their ability to self-update.

• The dynamic host agent downloads the latest set of sensors from repositories upon startup. By default, it updates itself daily to incorporate the newest capabilities. You can also precisely manage updates for dynamic host agents by pinning a version.

  Dynamic host agents are preferred for their ease of use and rapid integration of new capabilities, performance enhancements, and bug fixes. By default, dynamic host agents use the Instana repository for updates. However, in advanced scenarios, you can set up your own custom-managed mirror. For more information, see Configuring updates of dynamic host agents.

• The static host agent is a self-contained host agent that includes all the newest available components at the time of its release. However, this type of host agent cannot update itself.

  The static host agent maintains a stable "bill of materials" that remains unchanged after the host agent's installation. However, due to the absence of update capabilities, you must manage updates manually. For example, you can use infrastructure-as-code tools, such as Ansible or Terraform. Static host agents do not require an internet connection to the Instana repository and are to be used in restrictive network environments.

In general, use dynamic agents whenever possible. Static agents tend to get updated infrequently, which might result in missing new capabilities, performance improvements, and bug-fixes.

If you install a dynamic agent first, you cannot change it to a static agent. To change a static agent to a dynamic agent, see Converting a static agent to a dynamic agent.

Host agent modes

The Instana host agent has different modes of operation, in which it monitors its host and the applications that run on it to different extents:

• APM mode: This mode is the default mode. Here, the host agent provides the full Instana experience, including monitoring and tracing for every technology that Instana supports.

• OFF mode: In this mode, the host agent does not monitor its host and the applications, but periodically notifies the Instana backend that the agent is running idle.

• INFRASTRUCTURE mode: In this mode, the host agent monitors the underpinning host, and activates its sensors for technologies that are supported by Instana, but it does not trace applications.

• AWS mode: The one-liner host agent installation for Linux and the Instana host agent Docker image installation methods accept an extra mode, the AWS mode.

  The AWS mode of the host agent is not used for monitoring hosts. Instead, it functions similarly to the INFRASTRUCTURE mode but includes automatic configuration for AWS data collection, as described in the AWS Agent topic.

Instana container image repositories

Instana container images for the dynamic host agent are available on the IBM Cloud Container Registry (ICR), icr.io. The images can be downloaded without authentication from ICR.

Instana container images for the static host agent are available on Instana's own registry at containers.instana.io, which requires authentication with your agent key to access.

By default, host agents are deployed as dynamic host agents. To deploy the static host agent, change the deployment procedure to use the `containers.instana.io registry.