Overview

• supported ways + workarounds and tips
• stages / targets of configuration
• ifcfg files (/etc/sysconfig/network-scripts/ifcfg-*)
• supported device types
• limitations

Stages and targets of configuration

• installer
  • dracut stage - early configuration with dracut
  • anaconda stage - after switching to installer image root
• target system
  • configuration in installer: copied to target system
  • configuration in initial setup: is using anaconda GUI network config module - enabling networking for subscription manager
• live environment
  • use Live environment tools
    • better wireless support (mobile broadband)
• image install
  • livemedia-creator
  • anaconda --image=
  • don't touch system configuration

Dracut - early configuration in initramfs

• Installer runs its own dracut modules in initramfs (anaconda-dracut package)
• Why configure networking so early (before switching to installer image root)?
  • to fetch stuff (or use nfs) before the installer environment is run:
    • installer image (PXE boot)
    • updates.img
    • driver updates
    • kickstart
  • if boot options are preferred for some reason
    • eg for PXE booting

Dracut - boot options

• boot options
  • dracut: man dracut.cmdline
  • ip=ens3:dhcp
  • ip=10.34.102.223::10.34.102.254:255.255.255.0::ens3:none namserver=10.34.39.2
  • deprecated (RHEL 6) backward compatibility options (ksdevice)
• dracut defaults
  • used if early networking (initramfs) is required for installation and no boot options are specified
  • try ipv4 dhcp on each device - to avoid this, specify the device:
    • ip= option
    • via BOOTIF= option set by PXE config (ipappend 2)

Dracut - processing kickstart config

• kickstart network command

network --device=ens3 --bootproto static \
--ip 10.34.102.223 --netmask 255.255.255.0 --gateway 10.34.102.254 --nameserver 10.34.39.2 \
--activate --onboot=no

• kickstart config is translated into ifcfg files which are applied by NetworkManager after switching to installer root
  • /usr/sbin/parse-kickstart
• the kickstart config is applied in dracut stage - iff networking is not activated via boot options
  • eg ks is fetched from block device (ks=hd:LABEL=KICKSTARTDEV:/ks.cfg) or injected in initramfs (virt-install)
• for devices configured by dracut boot options ifcfg files are created as well
  • dracut's modules.d/45ifcfg/write-ifcfg.sh

Dracut - debugging

• TIP: edit ifcfg files before switch root (testing, debugging)
  • rd.break=pre-pivot boot option
  • first prompt: exit
  • second prompt: vi /run/initramfs/state/etc/sysconfig/network-scripts/ifcfg-ens3
  • exit

Anaconda - after switch root

• NetworkManager is started
  • takes over connections activated in initramfs
  • applies (if needed) ifcfg files created in initramfs (from kickstart)
  • missing configuration for a device
    • Fedora (workstation):
      • automatic default connections created and activated by NetworkManager
      • anaconda dumps in-memory connections to ifcfgs
    • RHEL (server):
      • anaconda creates default ifcfg files for devices not configured in initramfs
• kickstart
  • ifcfg files created in initramfs are used by NM started after switchroot
  • %pre kickstart section
    • create configuration dynamically at the beginning of installation after switch root
    • applied by anaconda calling NM dbus API to create and activate connections

%include /tmp/ksnetconf
%pre
echo "network --device ens9 --bootproto dhcp --activate --onboot=no" >> /tmp/ksnetconf
%end

Anaconda - after switch root - GUI/TUI

• GUI
  • prompt for config after Welcome screen for network installation
  • network spoke - using nm-connection-editor
  • TIP: nm-connection-editor started from tty2
    • DISPLAY=:1 nm-connection-editor
• TUI
  • limited to ethernet devices configuration
  • for bonding, vlan, ... use nmcli in tty2:
    • bonding example https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Networking_Guide/sec-Network_Bonding_Using_the_NetworkManager_Command_Line_Tool_nmcli.html

iBFT firmware configuration

• network configuration for iSCSI target to boot from
• ip=ibft boot option required
• dracut renames device to ibftX
• the option enables NetworkManager ibft plugin which takes it over and creates non-persistent connection based on iBFT automatically
  • ifcfg files are ignored in this case

Target system

• the persistent configuration from installer (ifcfg files) is copied to target system
  • a device configuration doesn't have to be applied in installer, but it (the ifcfg file) has to be created there
• kickstart --activate option
  • boot options device configuration for installer environment can be changed by kickstart or in UI
• kickstart --onboot option
• onboot policy in server / workstation
  • Fedora: enable a device with link

• dracut ip= boot options for root on network storage

• %post kickstart section
  • example: generating cloud images
    • https://git.fedorahosted.org/cgit/spin-kickstarts.git/tree/fedora-cloud-atomic.ks

%post
# simple eth0 config, again not hard-coded to the build hardware
cat > /etc/sysconfig/network-scripts/ifcfg-eth0 << EOF
DEVICE="eth0"
BOOTPROTO="dhcp"
ONBOOT="yes"
TYPE="Ethernet"
PERSISTENT_DHCLIENT="yes"
EOF
%end

Supported device types

network --device bond0 --bootproto=static \
--ip 10.34.107.233 --netmask 255.255.255.0 --gateway 10.34.107.255 --nameserver 10.34.107.1 \
--bondslaves=eth0,eth1 --bondopts=mode=active-backup,miimon=100,use_carrier=1 \
--onboot=no --activate --noipv6

• virtual: team, bond, vlan, bridge
  • boot options, kickstart, GUI
  • not TUI only displays active device in summary
    • use nmcli on tty2
• wireless
  • GUI (no kickstart, boot options)
  • Live CD environment

Limitations

• the same persistent configuration (ifcfg files) for installer and target system
• auto-apply of config change in GUI (Fedora)
• missing configuration of static routes
• NetworkManager and anaconda are started in parallel, anaconda doesn't wait for NM becoming online - opportrunity for race conditions