Bug 2000583

Summary:	Define primary and additional network gateway with multi-NIC installation
Product:	OpenShift Container Platform	Reporter:	Muhammad Adeel (IBM) <madeel>
Component:	Documentation	Assignee:	Silke Niemann <sniemann>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Xiaoli Tian <xtian>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	4.9	CC:	aos-bugs, miabbott, mtarsel, sniemann
Target Milestone:	---	Flags:	miabbott: needinfo-
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-03-02 17:20:56 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 Muhammad Adeel (IBM) 2021-09-02 12:41:27 UTC

Document URL: 
https://docs.openshift.com/container-platform/4.8/installing/installing_bare_metal/installing-bare-metal.html#installation-user-infra-machines-static-network_installing-bare-metal

Section Number and Name: 
Table 11. Networking and bonding options for ISO installations - After "Specify multiple network interfaces by specifying multiple ip= entries"

Describe the issue: 
If a user specify different gateway ip in ip= kernel argument, the NetworkManager could use the additional network gateway to fetch CoreOS rootfs. The additional network does not necessarily host an http and dns server. Therefore, it is necessary while doing multi-NIC installation, additional gateways must be defined separately with rd.core= instead of ip= kernel argument. 

Suggestions for improvement:
If the additional network interface gateway is different from the primary network interface, the default gateway must be the primary network interface.

In the next column:
The default gateway can be defined as:
ip=::10.10.10.254::::
Route for additional network can be defined as:
rd.route=20.20.20.0/24:20.20.20.254:enp2s0 

Additional information:

Comment 1 Silke Niemann 2021-09-15 08:50:56 UTC

I've verified with @micah.abbott that this works with x86 and have added then entry to the table in this PR: https://github.com/openshift/openshift-docs/pull/36250/

Comment 5 Silke Niemann 2022-03-02 17:20:56 UTC

Docs are updated PR has been merged