20.12. Configuring an 64-bit IBM Z network device for network root file system

To add a network device that is required to access the root file system, you only have to change the boot options. The boot options can be in a parameter file, however, the /etc/zipl.conf file no longer contains specifications of the boot records.

The file that needs to be modified can be located using the following commands:

# machine_id=$(cat /etc/machine-id)
# kernel_version=$(uname -r)
# ls /boot/loader/entries/$machine_id-$kernel_version.conf

Dracut, the mkinitrd successor that provides the functionality in the initramfs that in turn replaces initrd, provides a boot parameter to activate network devices on 64-bit IBM Z early in the boot process: rd.znet=.

As input, this parameter takes a comma-separated list of the NETTYPE (qeth, lcs, ctc), two (lcs, ctc) or three (qeth) device bus IDs, and optional additional parameters consisting of key-value pairs corresponding to network device sysfs attributes. This parameter configures and activates the 64-bit IBM Z network hardware. The configuration of IP addresses and other network specifics works the same as for other platforms. See the dracut documentation for more details.

The cio_ignore commands for the network channels are handled seamlessly on boot.

Example boot options for a root file system accessed over the network through NFS:

root=10.16.105.196:/nfs/nfs_root cio_ignore=all,!condev rd.znet=qeth,0.0.0a00,0.0.0a01,0.0.0a02,layer2=1,portno=0,portname=OSAPORT ip=10.16.105.197:10.16.105.196:10.16.111.254:255.255.248.0:nfs‑server.subdomain.domain:enc9a0:none rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us