Host agents

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

Host agent types

The Instana host agent has two types, dynamic and static, based on whether it can update itself or not.

  • Dynamic host agent: A host agent that downloads on startup the latest set of sensors from repositories. By default, a dynamic agent updates itself daily with the latest and greatest capabilities that are 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 quick turn-around in acquiring new capabilities, performance improvements, and bug-fixes. By default, dynamic host agents use the Instana repository to pull updates. But in advanced use-cases, it is possible to set up your own managed mirror. For more information about how host agent updates can be configured, see the Host agent updates.

  • Static host agent: A self-contained host agent that includes all the latest available components at the time of its release, and has no dynamic update capabilities.

    The static host agent has a stable "bill of materials" that never changes after the host agent's installation. However, the lack of update capabilities means that you need to provide your own way of keeping Instana agents up-to-date, such as using 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, you are recommended to use dynamic agents whenever possible. Static agents tend to get updated infrequently, and that makes you miss new capabilities, performance improvements and bug-fixes.

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:

  • OFF mode: In this mode, the host agent will not monitor, but only notify at regular intervals the Instana backend that it is running idle.
  • INFRASTRUCTURE mode: In this mode, the host agent monitors the underpinning host, and activates its sensors for every technology that are supported by Instana, but it doesn't perform any tracing of applications.
  • APM mode: The default mode. In this mode, the host agent provides the full Instana experience, including monitoring and tracing for every technology that is supported by Instana.

Notes:

  • The One-Liner host agent installation method and the Instana host agent Docker image methods accept an extra mode, the AWS mode.

    The AWS mode of the host agent is not used for monitoring hosts. It is the INFRASTRUCTURE mode plus some automatic configuration of AWS data collection, as described in the AWS Agent documentation.

  • Host agent modes can be changed after the host agent is installed by using the Agent Management dashboard. For more information, see the Configuring host agent mode documentation.

Changes to the Instana container image repositories

All Instana container images that are publicly available on Docker Hub are migrated to the IBM Cloud Container Registry (ICR). The images can be downloaded without authentication from ICR. Images that are made available by using Instana's own registry at containers.instana.io are not affected by this change.

Affected Instana images

Docker Hub Image IBM Cloud Container Registry Image Note
instana/agent icr.io/instana/agent No change for containers.instana.io/instana/release/agent/*
instana/aws-fargate-nodejs icr.io/instana/aws-fargate-nodejs No change for containers.instana.io/instana/release/aws/fargate/nodejs
instana/aws-lambda-nodejs icr.io/instana/aws-lambda-nodejs
instana/google-cloud-run-nodejs icr.io/instana/google-cloud-run-nodejs No change for containers.instana.io/instana/release/google/cloud-run/nodejs
instana/instana-agent-operator icr.io/instana/instana-agent-operator
instana/leader-elector icr.io/instana/leader-elector
instana/instrumentation icr.io/instana/instrumentation

Existing image repositories on Docker Hub's container image registry will be kept around until at least June 2022, but images in these repositories will not be updated anymore. Only the repositories on ICR will receive updates. At some point after July 2022, the Docker Hub image repositories will become unavailable.

Affected Resources

See the following affected resources:

  • Static Kubernetes deployment YAML
  • Agent Helm chart
  • Agent Operator
  • Autotrace Webhook
  • Serverless image layers

Automatic Updates

After all images are migrated to ICR, Instana will adopt the migration with the next releases of the affected resources. New installations and updating from the agent Helm chart, agent Operator or Autotrace Webhook will reference the new ICR repositories. In addition, the static Kubernetes deployment YAML will reference the new agent repository.

Manual Customer Interaction

You are affected by this migration, and need to adjust manually when you pull Instana images in the following cases:

  • Static Kubernetes deployment YAML as pulled from Instana documentation or "Installing Instana Agents" wizard.
  • Proxy Instana Docker images from Docker Hub in private container image repositories.
  • Use automation scripts to install dockerized agents.
  • Build Node.js-based Fargate task container images and Google Cloud Run service images, which use Instana images as a base image.

Manual adjustment: Change any reference to Instana images to icr.io/<image-repo-name>. Because Docker Hub is the default registry, images are typically referenced just by using the repository name. For example, instana/agent references the dynamic Instana agent on Docker Hub. This needs to be adjusted to icr.io/instana/agent. instana/instrumentation:latest references the Autotrace Webhook instrumentation image. This needs to be adjusted to icr.io/instana/instrumentation:latest.

Installing, configuring, and managing