Bug 1466933 - Spam to API server is causing too many etcd writes
Summary: Spam to API server is causing too many etcd writes
Alias: None
Product: OpenShift Container Platform
Classification: Red Hat
Component: Node
Version: 3.6.0
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
: 3.7.0
Assignee: Derek Carr
QA Contact: Mike Fiedler
Depends On:
Blocks: 1467022
TreeView+ depends on / blocked
Reported: 2017-06-30 19:34 UTC by Derek Carr
Modified: 2017-11-28 21:59 UTC (History)
7 users (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
Feature: control event spam to masters Reason: internal controllers can send large numbers of events when an object is unable to reach its desired state. in large clusters, this can cause excessive writes to etcd. Result: event client has been updated to protect against spamming master components. objects have an initial event budget of 25 events with a refill rate of 1 event every 5 minutes. this controls traffic to the masters and reduces writes to etcd.
Clone Of:
: 1467022 (view as bug list)
Last Closed: 2017-11-28 21:59:33 UTC
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2017:3188 0 normal SHIPPED_LIVE Moderate: Red Hat OpenShift Container Platform 3.7 security, bug, and enhancement update 2017-11-29 02:34:54 UTC

Description Derek Carr 2017-06-30 19:34:03 UTC
Description of problem:

A large cluster with either of the following:

1. a large amount of HPAs
2. a large amount of pods that are always unhealthy

is causing too many writes to the API server and inducing excessive snapshot of etcd.

Version-Release number of selected component (if applicable):
OCP 3.6.0

How reproducible:

Steps to Reproduce:
See above

Actual results:
spam should be reduced to masters

Expected results:
HPA should only send status updates if status changes
Pods in perpetual failure status should not spam masters with events

Additional info:

Comment 1 Derek Carr 2017-06-30 20:28:27 UTC
Two fixes were identified:


this sets a budget of events about an object.
per source+object event budget of 25 burst with refill of 1 every 5 minutes.
it will reduce the long tail of events sent about objects in perpetual failure states (pod in crash loop backoff, controllers denied by quota, etc.).

HPA only sends status updates if status changes.

Comment 2 Eric Paris 2017-07-01 20:14:14 UTC
I'm using this bz to track only 

The HPA fix is tracked in 1467022

Comment 4 DeShuai Ma 2017-07-05 08:06:22 UTC
Hi Mike, help verify the bug, thanks.

Comment 5 Mike Fiedler 2017-07-06 21:01:00 UTC
Verified during an event storm caused by misconfigured DNS.  api servers were not getting unique PUTs for each event recorded by the kubelet.   v3.6.126.1

Comment 9 errata-xmlrpc 2017-11-28 21:59:33 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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