Tuesday, May 23, 2023

WARNING: Updating from RHEL8.6 to RHEL8.7/RHEL8.8 may break Network Access with RoCE Express Adapters

RoCE interfaces may lose their IP settings due to an unexpected change of the network interface name.

The RoCE Express adapters can lose their IP settings due to an unexpected change of the network interface name if both of the following conditions are met:

  • User upgrades from a RHEL 8.6 system or earlier.
  • The RoCE card is enumerated by UID.

To workaround this problem:

Create the file /etc/systemd/network/98-rhel87-s390x.link with the following content:

[Match]
Architecture=s390x
KernelCommandLine=!net.naming-scheme=rhel-8.7

[Link]
NamePolicy=kernel database slot path
AlternativeNamesPolicy=database slot path
MACAddressPolicy=persistent

After rebooting the system for the changes to take effect, you can safely upgrade to RHEL 8.7 or later.

Note:
RoCE interfaces that are enumerated by function ID (FID, indicated by featuring the prefix ens in their interface names) are not unique and not affected by this issue. Set the kernel parameter net.naming-scheme=rhel-8.7. to switch to predictable interface names with the eno prefix. See the Networking with RoCE Express book for further details.

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