Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Kubernetes Pod Probes

Tim Hockin
January 17, 2023

Kubernetes Pod Probes

I am a visual-thinker, so it helps me to have diagrams!

Tim Hockin

January 17, 2023
Tweet

More Decks by Tim Hockin

Other Decks in Technology

Transcript

  1. Kubernetes Pod Probes
    @thockin
    Jan. 2023

    View full-size slide

  2. NOTE: This documents logical behavior. The
    code may not actually be modelled this way.

    View full-size slide

  3. // Probe describes a health check to be performed against a container to determine whether it is
    // alive or ready to receive traffic.
    type Probe struct {
    // ...
    // Number of seconds after the container has started before liveness probes are initiated.
    // More info: https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle#container-probes
    InitialDelaySeconds int32
    // Number of seconds after which the probe times out.
    // Defaults to 1 second. Minimum value is 1.
    TimeoutSeconds int32
    // How often (in seconds) to perform the probe.
    // Default to 10 seconds. Minimum value is 1.
    PeriodSeconds int32
    // Minimum consecutive successes for the probe to be considered successful after having failed.
    // Defaults to 1. Must be 1 for liveness and startup. Minimum value is 1.
    SuccessThreshold int32
    // Minimum consecutive failures for the probe to be considered failed after having succeeded.
    // Defaults to 3. Minimum value is 1.
    FailureThreshold int32
    // ...
    }

    View full-size slide

  4. startupProbe
    Waiting Probing
    Failing
    container
    start
    `initial
    Delay
    Seconds`
    `timeout
    Seconds`
    `failure
    Threshold`
    reached
    Passing
    fail
    pass
    `successThreshold` is
    required to be 1 for
    `startupProbe`
    restart
    container
    `period
    Seconds`
    Passed
    `success
    Threshold`
    reached
    continue
    `startupProbe` is done
    and will not be
    revisited unless the
    container restarts

    View full-size slide

  5. livenessProbe
    Waiting Probing
    Failing
    `initial
    Delay
    Seconds`
    `timeout
    Seconds`
    `failure
    Threshold`
    reached
    Passing
    fail
    pass
    `successThreshold` is
    required to be 1 for
    `livenessProbe`
    restart
    container
    `period
    Seconds`
    `period
    Seconds`
    Passed
    `success
    Threshold`
    reached
    `livenessProbe` does
    not start until
    `startupProbe`
    completes (if defined)

    View full-size slide

  6. readinessProbe
    Waiting Probing
    Failing
    `initial
    Delay
    Seconds`
    `timeout
    Seconds`
    `failure
    Threshold`
    reached
    Passing
    fail
    pass
    `period
    Seconds`
    `period
    Seconds`
    Ready
    Unready
    `period
    Seconds`
    `success
    Threshold`
    reached
    `period
    Seconds`
    `readinessProbe`
    does not start until
    `startupProbe`
    completes (if defined)
    `failureThreshold` is a
    consecutive count -
    any “pass” result
    resets the counter
    `successThreshold` is
    a consecutive count -
    any “fail” result resets
    the counter

    View full-size slide