Address key open items and move KEP to implementable state

vinaykul · Oct 28, 2019 · 29d95bc · 29d95bc
1 parent 3d11c28
commit 29d95bc
Showing 1 changed file with 19 additions and 2 deletions.
diff --git a/keps/sig-autoscaling/20181106-in-place-update-of-pod-resources.md b/keps/sig-autoscaling/20181106-in-place-update-of-pod-resources.md
@@ -23,8 +23,8 @@ approvers:
   - "@mwielgus"
 editor: TBD
 creation-date: 2018-11-06
-last-updated: 2018-11-06
-status: provisional
+last-updated: 2019-10-25
+status: implementable
 see-also:
 replaces:
 superseded-by:
@@ -49,6 +49,7 @@ superseded-by:
          * [Scheduler and API Server interaction](#scheduler-and-api-server-interaction)
          * [Flow Control](#flow-control)
             * [Container resource limit update ordering](#container-resource-limit-update-ordering)
+            * [Container resource limit update failure handling](#container-resource-limit-update-failure-handling)
             * [Notes](#notes)
          * [Affected Components](#affected-components)
          * [Future Enhancements](#future-enhancements)
@@ -167,6 +168,12 @@ Kubelet calls UpdateContainerResources CRI API which currently takes
 but not for Windows. This parameter changes to *runtimeapi.ContainerResources*,
 that is runtime agnostic, and will contain platform-specific information.
 
+Additionally, GetContainerResources CRI API is introduced that allows Kubelet
+to query currently configured CPU and memory limits for a container.
+
+These CRI changes are a separate effort that does not affect the design
+proposed in this KEP.
+
 ### Kubelet and API Server Interaction
 
 When a new Pod is created, Scheduler is responsible for selecting a suitable
@@ -283,6 +290,16 @@ updates resource limit for the Pod and its Containers in the following manner:
 In all the above cases, Kubelet applies Container resource limit decreases
 before applying limit increases.
 
+#### Container resource limit update failure handling
+
+If multiple Containers in a Pod are being updated, and UpdateContainerResources
+CRI API fails for any of the containers, Kubelet will backoff and retry at a
+later time. Kubelet does not attempt to update limits for containers that are
+lined up for update after the failing container. This ensures that sum of the
+container limits does not exceed Pod-level cgroup limit at any point. Once all
+the container limits have been successfully updated, Kubelet updates the Pod's
+Status.ContainerStatuses[i].Resources to match the desired limit values.
+
 #### Notes
 
 * If CPU Manager policy for a Node is set to 'static', then only integral