Bug 1261634

Summary: [RFE] Calculate the pmtu instead of hardcoding it
Product: OpenShift Container Platform Reporter: Ricardo Martinelli de Oliveira <rmartine>
Component: RFEAssignee: Mike Barrett <mbarrett>
Status: CLOSED CURRENTRELEASE QA Contact: Meng Bo <bmeng>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 3.1.0CC: aos-bugs, jokerman, mmccomas, xtian
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-11-23 14:25:18 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 Ricardo Martinelli de Oliveira 2015-09-09 19:35:46 UTC 
Description of problem:

Currently the mtu is hardcoded to 1450. While this works for most cases, its not valid when the assumed underlay is an overlay itself. Also, if customer need to use jumbo frames it requires a global change.

Reference:

https://github.com/openshift/openshift-sdn/issues/120
Comment 3 Meng Bo 2015-10-19 07:35:13 UTC 
Checked on puddle 2015.10.17-1

The MTU is configurable in node-config instead of hardcoding. 


For mtu 1450:
# oc rsh hello-pod
bash-4.3$ ip a 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
14: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue 
    link/ether 02:42:0a:01:00:04 brd ff:ff:ff:ff:ff:ff
    inet 10.1.0.4/24 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:aff:fe01:4/64 scope link 
       valid_lft forever preferred_lft forever


For mtu 1000:
# oc rsh hello-pod
bash-4.3$ ip a 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
21: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1000 qdisc noqueue 
    link/ether 02:42:0a:01:00:02 brd ff:ff:ff:ff:ff:ff
    inet 10.1.0.2/24 scope global eth0
       valid_lft forever preferred_lft forever


Verify the bug.
Comment 4 Brenton Leanhardt 2015-11-23 14:25:18 UTC 
This fix is available in OpenShift Enterprise 3.1.