How to Perform an In-Place Upgrade when Using Kernel-Assigned NIC Names

Resolution

To prepare the system for an in-place upgrade, you must migrate it to another naming scheme.

To do so, you can apply:

• A naming scheme provided by systemd-udev (see [1] for more details)
• Your own interface names

Red Hat suggests to use your own naming scheme, because having sensible NIC names on machines with multiple interfaces can also simplify the system administration and maintenance.

Use either the manual method or Ansible-based method to migrate to the new naming scheme.

Manual method

You can implement your own name scheme using udev rules, as shown in the example below:

• Create a udev rules file in the /etc/udev/rules.d/ directory, such as /etc/udev/rules.d/10-persistent.rules

# MAC address match. Will name the device with the specified MAC address the value given in the NAME property:
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="xx:xx:xx:xx:xx:xx", ATTR{type}=="1", KERNEL=="*", NAME="my_nic_2"

You can see this article for more information on how to assign a specific interface name

To make sure that interfaces have the correct names during the early boot phase, include the udev rules to an initrd image:

# mkdir -p /etc/dracut.conf.d
# echo install_items+=\" /etc/udev/rules.d/10-persistent.rules \" > /etc/dracut.conf.d/include-nic-names-rules.conf
# dracut -f

On the following kernel upgrade, the rules will be included to the initrd image automatically.

If the old interface names were embedded in both local configuration files (ifcfg-* files, NetworkManager configuration, firewalld configuration, iptables rules) and remote configuration, such as playbooks stored in Ansible Tower, you must migrate them to account for the new names.

IMPORTANT After making the above changes, reboot the system and then check the output of # ip a to verify the NIC names have changed to the new prefix.

[1] Consistent Network Device Naming

Ansible-based method

The 4067471_predictable-nics.yml attachment is a playbook that migrates all NICs with the eth prefix to a new naming scheme. The playbook includes the following operations:

• Adds a udev rules file with the new NIC name to MAC address assignments
• Renames and updates all eth device files to the new NIC naming scheme
• Renames and updates all eth route files to the new NIC naming scheme
• Performs a final regex on all ifcfg-* files to convert any eth devices to the new naming scheme

The 4067471_predictable-nics.yml playbook accommodates most networking scenarios that use Ethernet devices, bridges, and bonds. If your environment requires additional configuration beyond these device types, follow these recommendations before proceeding:

• Test the playbook on a system with a similar networking configuration to production systems
• Modify the playbook to accommodate renaming the eth prefix within the configuration of other device types
• Check the networking configuration of your systems after you run the playbook

To use this playbook, download the attached playbook to your Ansible control host (saving it as 4067471_predictable-nics.yml) and run the playbook against an inventory of your hosts:

$ ansible-playbook -i ~/inventory 4067471_predictable-nics.yml

The playbook renamed eth interfaces to em by default. To use different source and destination names, use the src_prefix and dst_prefix variables when running the playbook:

$ ansible-playbook -i ~/inventory -e dst_prefix="mynic" 4067471_predictable-nics.yml

When the playbook completes its tasks, reboot your systems and check that the NICs on each system use the new naming scheme.