Checking the agent prerequisites on Kubernetes

Before you install the agent, make sure that all the necessary prerequisite conditions are met. See the following sections for the necessary prerequisite conditions:

Prerequisites

Before you install the agent, check the following topics:

  1. Check whether you have a supported Kubernetes version.

  2. Check whether the network requirements for agents are met as described in network requirements for Instana agent.

  3. The Instana agent has deep access into the observed system where it is installed. Check security considerations when the agent is running as described in Host agent security considerations.

  4. Different versions of the Instana agent appear in the Instana UI and in the documentation. Check the various versions as described in Host agent versioning.

  5. If you want to install the agent in an air-gapped environment, ensure that following environment and tools are ready:

    • Linux CentOS 7 or 8
    • Docker
    • Helm
    • Minikube
    • Instana helm-charts

JVM monitoring prerequisites

The Instana host agent creates temporary JAR files in the $TMP/.instana directory. These JAR files are required for the JVM monitoring. For successful JVM monitoring, ensure that the root user that runs the agent and the user that runs the JVM have the necessary read and write permissions for the $TMP directory.

If the $TMP directory on the host has enforced read-only permissions (readOnlyRootFilesystem: true), you must add the following configuration to the Java workloads to ensure successful monitoring. By using the configuration, the agent can write files to the $TMP location.

    securityContext:
      ...
      readOnlyRootFilesystem: true
    volumeMounts:
    - name: tmp-volume
      mountPath: /tmp
  volumes:
  - name: tmp-volume
    emptyDir: {}

By adding the above configuration to the Java workloads with enforced readOnlyRootFilesystem, agent can write files to $TMP location.