From c9aace3c09847b2178a8bfaf9bda162a4d8aeac2 Mon Sep 17 00:00:00 2001 From: Naoki Oketani Date: Sun, 9 Feb 2020 04:49:53 +0900 Subject: [PATCH] cleanup /docs/concepts/workloads/pods/pod-lifecycle/ (#19009) --- .../concepts/workloads/pods/pod-lifecycle.md | 28 ++++++++----------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/content/en/docs/concepts/workloads/pods/pod-lifecycle.md b/content/en/docs/concepts/workloads/pods/pod-lifecycle.md index 772d7b3a6d462..b54a8b6ca8bcc 100644 --- a/content/en/docs/concepts/workloads/pods/pod-lifecycle.md +++ b/content/en/docs/concepts/workloads/pods/pod-lifecycle.md @@ -55,7 +55,7 @@ array has six possible fields: * The `message` field is a human-readable message indicating details about the transition. - + * The `reason` field is a unique, one-word, CamelCase reason for the condition's last transition. * The `status` field is a string, with possible values "`True`", "`False`", and "`Unknown`". @@ -183,18 +183,18 @@ Once Pod is assigned to a node by scheduler, kubelet starts creating containers Reason: ErrImagePull ... ``` - -* `Running`: Indicates that the container is executing without issues. The `postStart` hook (if any) is executed prior to the container entering a Running state. This state also displays the time when the container entered Running state. - + +* `Running`: Indicates that the container is executing without issues. The `postStart` hook (if any) is executed prior to the container entering a Running state. This state also displays the time when the container entered Running state. + ```yaml ... State: Running Started: Wed, 30 Jan 2019 16:46:38 +0530 ... - ``` - + ``` + * `Terminated`: Indicates that the container completed its execution and has stopped running. A container enters into this when it has successfully completed execution or when it has failed for some reason. Regardless, a reason and exit code is displayed, as well as the container's start and finish time. Before a container enters into Terminated, `preStop` hook (if any) is executed. - + ```yaml ... State: Terminated @@ -203,7 +203,7 @@ Once Pod is assigned to a node by scheduler, kubelet starts creating containers Started: Wed, 30 Jan 2019 11:45:26 +0530 Finished: Wed, 30 Jan 2019 11:45:26 +0530 ... - ``` + ``` ## Pod readiness gate @@ -214,7 +214,7 @@ extra feedback or signals into `PodStatus`, Kubernetes 1.11 introduced a feature named [Pod ready++](https://github.com/kubernetes/enhancements/blob/master/keps/sig-network/0007-pod-ready%2B%2B.md). You can use the new field `ReadinessGate` in the `PodSpec` to specify additional conditions to be evaluated for Pod readiness. If Kubernetes cannot find such a -condition in the `status.conditions` field of a Pod, the status of the condition +condition in the `status.conditions` field of a Pod, the status of the condition is default to "`False`". Below is an example: ```yaml @@ -253,12 +253,6 @@ when both the following statements are true: To facilitate this change to Pod readiness evaluation, a new Pod condition `ContainersReady` is introduced to capture the old Pod `Ready` condition. -In K8s 1.11, as an alpha feature, the "Pod Ready++" feature has to be explicitly enabled by -setting the `PodReadinessGates` [feature gate](/docs/reference/command-line-tools-reference/feature-gates/) -to true. - -In K8s 1.12, the feature is enabled by default. - ## Restart policy A PodSpec has a `restartPolicy` field with possible values Always, OnFailure, @@ -275,8 +269,8 @@ once bound to a node, a Pod will never be rebound to another node. ## Pod lifetime In general, Pods remain until a human or controller process explicitly removes them. -The control plane cleans up terminated Pods (with a phase of `Succeeded` or -`Failed`), when the number of Pods exceeds the configured threshold +The control plane cleans up terminated Pods (with a phase of `Succeeded` or +`Failed`), when the number of Pods exceeds the configured threshold (determined by `terminated-pod-gc-threshold` in the kube-controller-manager). This avoids a resource leak as Pods are created and terminated over time.