How to define a persistent HSCI interface in Ubuntu 22.04

1. Remove external/OSA and HiperSockets (HS) devices from the ignore list.

   $ cio_ignore -r 0.0.8000-0.0.8002
   $ cio_ignore -r 0.0.b000-0.0.b002

2. Enable Layer2 for HS device and activate both devices.

   $ chzdev -e 0.0.8000 layer2=1
   $ chzdev -e 0.0.b000 vnicc/flooding=1 vnicc/mcast_flooding=1

   Create netplan entries for all devices - HiperSockets, OSA and HSCI.

   $/etc/netplan/10-enc8000-config.yaml

   network:
     ethernets:
       enc8000:
         dhcp4: false
         dhcp6: false
     version: 2

   $ /etc/netplan/11-encb000-config.yaml

   network:
     ethernets:
       encb000:
         dhcp4: false
         dhcp6: false
     version: 2

   $ /etc/netplan/99-hsci8000-config.yaml

   network:
     ethernets:
       hsci8000:
         addresses:
         - 10.30.83.24/16
         dhcp4: false
         dhcp6: false
     version: 2

   This hsci yaml file defines the network configuration for the hsci8000 device, which is generated at every (re)boot.

3. Check the new network configuration under /etc/netplan.

   $ ls -1 /etc/netplan
     00-installer-config.yaml
     10-enc8000-config.yaml
     11-encb000-config.yaml
     99-hsci8000-config.yaml

4. Apply the new created network configuration.

   $ netplan apply

5. Persist HSCI using networkd-dispatcher.

   networkd-dispatcher is the counterpart to the nm-dispatcher of the NetworkManager and runs shell scripts in /etc/networkd-dispatcher/ (and /usr/lib/networkd-dispatcher/). There are subdirectories, which correspond to the possible states of the network interfaces and the scripts stored in these subdirectories run depending on the status of the interface.

   1. networkd-dispatcher states: https://wiki.ubuntuusers.de/systemd/networkd-dispatcher/.

   2. Create the 100-hsci8000-mm-setup_ubuntu22.04+.sh-script in /etc/networkd-dispatcher/degraded.d/.

      You don’t need to create the HSCI interface manually. Simply add the following script 100-hsci8000-mm-setup_ubuntu22.04+.sh and reboot the system.

      HSCI information

      $ which hsci
        /usr/sbin/hsci
      $ hsci --version
        hsci utility: version 2.20.0-build-20220413
        Copyright IBM Corp. 2020

      Do not forget to change interface names in the script to match your real interface names.

#!/usr/bin/env bash

HS_DEV=enc8000
EXT_DEV=encb000
HSCI_DEV=hsci8000

TMPFILE=/tmp/networkd-dispatcher-results
echo "$IFACE is in STATE: $STATE" >> $TMPFILE

################################################################################
# Check if HSCI already exists

if [[ $(ip link show $HSCI_DEV | grep UP | wc -l) -eq 1 ]]; then
        logger "hsci-networkd-dispatcher $0: $HSCI_DEV is already in STATE: UP and running. \
                Exit script here!"
        exit 0
fi

################################################################################
# Check,
#   if received device is a HS bridgport
#   if the other HSCI bridgport (OSA) is UP
# Then run "hsci add ..."
if [[ $IFACE == $HS_DEV ]] && [[ $(ip link show $EXT_DEV | grep UP | wc -l) -eq 1 ]]; then
        logger "hsci-networkd-dispatcher $0: $IFACE matched $HS_DEV, and $EXT_DEV is UP "
        /usr/sbin/hsci add $HS_DEV $EXT_DEV
fi

################################################################################
# Check,
#   if received device is a OSA bridgport
#   if the other HSCI bridgport (HS) is UP
# Then run "hsci add ..."
if [[ $IFACE == $EXT_DEV ]] && [[ $(ip link show $HS_DEV | grep UP | wc -l) -eq 1 ]]; then
        logger "hsci-networkd-dispatcher $0: $IFACE matched $EXT_DEV, and $HS_DEV is UP "
        /usr/sbin/hsci add $HS_DEV $EXT_DEV
fi