Bug 1371309

Summary:	enable pods-per-core and max-pods in node configuration
Product:	OpenShift Container Platform	Reporter:	Jeremy Eder <jeder>
Component:	Node	Assignee:	Derek Carr <decarr>
Status:	CLOSED ERRATA	QA Contact:	Weihua Meng <wmeng>
Severity:	high	Docs Contact:
Priority:	high
Version:	3.3.1	CC:	aos-bugs, dma, jokerman, mifiedle, mmccomas, sdodson, tdawson, tstclair, wmeng
Target Milestone:	---	Keywords:	NeedsTestCase
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	No Doc Update
Doc Text:	undefined	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-01-18 12:52:37 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Jeremy Eder 2016-08-29 20:51:13 UTC

Description of problem:

In the kubernetes 1.3 cycle, we added a feature to get away from a single max-pods value.

https://github.com/kubernetes/kubernetes/pull/25813

"pods-per-core" is a simple scaling factor that allows us to get past the previous limit of 110 on larger systems.

OpenShift should lay down a config like so (via installer):

--pods-per-core=10 
--max-pods=250

Which, when compared with openshift 3.2 max-pods=110, the effective behavior of the new pods-per-core algorithm:

For 1-10 cores, max-pods is reduced
For 11+ cores, max-pods is increased

Examples:

8 cores:
8 cores * pods-per-core(10) = 80
80 < max-pods, so the limit is 80 pods.

16 cores:
16 cores * pods-per-core(10) = 160
160 < max-pods, so the limit is 160 pods.

32 cores * pods-per-core(10) = 320
320 > max-pods, so max-pods wins and the limit is 250

Comment 7 Weihua Meng 2016-11-03 09:37:24 UTC

Verified, Fixed.
openshift v3.4.0.19+346a31d
kubernetes v1.4.0+776c994
etcd 3.1.0-rc.0

1. --pods-per-core=10
Capacity:
 alpha.kubernetes.io/nvidia-gpu:	0
 cpu:					2
 memory:				3881932Ki
 pods:					20
Allocatable:
 alpha.kubernetes.io/nvidia-gpu:	0
 cpu:					2
 memory:				3881932Ki
 pods:					20

2. --pods-per-core=0
Capacity:
 alpha.kubernetes.io/nvidia-gpu:	0
 cpu:					2
 memory:				3881932Ki
 pods:					250
Allocatable:
 alpha.kubernetes.io/nvidia-gpu:	0
 cpu:					2
 memory:				3881932Ki
 pods:					250

Comment 9 errata-xmlrpc 2017-01-18 12:52:37 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.

https://access.redhat.com/errata/RHBA-2017:0066