Kubernetes Troubleshoot a Failing Pod

arazzo: 1.0.1
info:
  title: Kubernetes Troubleshoot a Failing Pod
  summary: Find pods that are not Running, read the failing pod's detail, tail its logs, and pull namespace events.
  description: >-
    The triage loop every operator runs by hand, expressed as a workflow. It
    filters the namespace for pods that are not in the Running phase, reads the
    first offender for its container statuses and conditions, tails its log for
    an application-level cause, and lists namespace events for the
    cluster-level cause such as a failed image pull or a scheduling constraint.
    Every step spells out its request inline so the flow can be read and
    executed without opening the underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: kubernetesApi
  url: ../openapi/kubernetes-api-openapi.yml
  type: openapi
workflows:
- workflowId: troubleshoot-pod
  summary: Locate a non-Running pod and gather its detail, logs, and related events.
  description: >-
    Lists pods filtered by a field selector on status.phase, and when a match is
    found reads the pod, tails its log, and lists namespace events to explain
    the failure. Ends early when every pod is healthy.
  inputs:
    type: object
    required:
    - namespace
    properties:
      namespace:
        type: string
        description: The namespace to triage.
      phaseSelector:
        type: string
        description: Field selector isolating unhealthy pods (e.g. status.phase!=Running).
      labelSelector:
        type: string
        description: Optional label selector narrowing triage to one application.
      container:
        type: string
        description: Container to read logs from in a multi-container pod.
      tailLines:
        type: integer
        description: Number of log lines to retrieve from the end of the log.
  steps:
  - stepId: findUnhealthyPods
    description: >-
      List pods in the namespace filtered to those not in the Running phase.
      When nothing matches, the namespace is healthy and the flow ends.
    operationId: listNamespacedPods
    parameters:
    - name: namespace
      in: path
      value: $inputs.namespace
    - name: fieldSelector
      in: query
      value: $inputs.phaseSelector
    - name: labelSelector
      in: query
      value: $inputs.labelSelector
    - name: limit
      in: query
      value: 100
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      unhealthyPods: $response.body#/items
      firstPodName: $response.body#/items/0/metadata/name
    onSuccess:
    - name: foundUnhealthyPod
      type: goto
      stepId: readPodDetail
      criteria:
      - context: $response.body
        condition: $.items.length > 0
        type: jsonpath
    - name: allPodsHealthy
      type: end
      criteria:
      - context: $response.body
        condition: $.items.length == 0
        type: jsonpath
  - stepId: readPodDetail
    description: >-
      Read the failing pod for its phase, node assignment, IPs, and conditions,
      which distinguish a scheduling failure from a container-level failure.
    operationId: getNamespacedPod
    parameters:
    - name: namespace
      in: path
      value: $inputs.namespace
    - name: name
      in: path
      value: $steps.findUnhealthyPods.outputs.firstPodName
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      podName: $response.body#/metadata/name
      phase: $response.body#/status/phase
      hostIP: $response.body#/status/hostIP
      podIP: $response.body#/status/podIP
      startTime: $response.body#/status/startTime
      conditions: $response.body#/status/conditions
  - stepId: tailPodLog
    description: >-
      Tail the container log for an application-level cause such as a crash on
      startup or a failed dependency check.
    operationId: readNamespacedPodLog
    parameters:
    - name: namespace
      in: path
      value: $inputs.namespace
    - name: name
      in: path
      value: $steps.readPodDetail.outputs.podName
    - name: container
      in: query
      value: $inputs.container
    - name: follow
      in: query
      value: false
    - name: tailLines
      in: query
      value: $inputs.tailLines
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      logOutput: $response.body
  - stepId: readNamespaceEvents
    description: >-
      List namespace events to surface the cluster-level cause the pod object
      alone does not carry, such as ImagePullBackOff or FailedScheduling.
    operationId: listNamespacedEvents
    parameters:
    - name: namespace
      in: path
      value: $inputs.namespace
    - name: limit
      in: query
      value: 100
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      events: $response.body#/items
  outputs:
    podName: $steps.readPodDetail.outputs.podName
    phase: $steps.readPodDetail.outputs.phase
    conditions: $steps.readPodDetail.outputs.conditions
    logOutput: $steps.tailPodLog.outputs.logOutput
    events: $steps.readNamespaceEvents.outputs.events