NetworkManager Merges An Initrd Generator For Early Boot Handling

[phoronix]

Phoronix: NetworkManager Merges An Initrd Generator For Early Boot Handling

Days following the NetworkManager 1.14 release, feature activity on the next release is progressing and the newest addition is nm-initrd-generator...

http://www.phoronix.com/scan.php?page=news_item&px=NetworkManager-Initrd-Gen

[boxie]

I am trying to figure out the use cases for this, the main one I have come up with is the PXE boot process that would help out the initial OS load.

what else?

[lkundrak]

I am trying to figure out the use cases for this, the main one I have come up with is the PXE boot process that would help out the initial OS load.

what else?

Yes, exactly this. Currently, the early boot network configuration is usually pretty hacky and distro-specific. Typically a bunch of shell scripts crunch the command line and configure (create, in case of bonds, vlans, etc.) the interfaces, bring them up and eventually start and stop dhclient. After the real init is run and NetworkManager is started, guesswork is needed to identify the connections activated on early boot (so that DHCP addresses are renewed and so on.)

The part that has now been merged parses the same command line arguments (in a compatible manner) but instead of applying things it generates NetworkManager configuration in /run. Then an instance of NetworkManager can be run to apply the configuration, write a state file in /run, and exit. After the root is mounted and the real init runs the NetworkManager service, it can get an idea of what has been configured already by reading stuff from there. No guesswork needed.

The aim is to clean up the network boot process and reuse the broad network device support NetworkManager has. A nice side-advantage is that NetworkManager can do DHCP without dhclient with its internal (systemd-networkd based) DHCP client, that for some reason ends up being faster.

[boxie]

Yes, exactly this. Currently, the early boot network configuration is usually pretty hacky and distro-specific. Typically a bunch of shell scripts crunch the command line and configure (create, in case of bonds, vlans, etc.) the interfaces, bring them up and eventually start and stop dhclient. After the real init is run and NetworkManager is started, guesswork is needed to identify the connections activated on early boot (so that DHCP addresses are renewed and so on.)

The part that has now been merged parses the same command line arguments (in a compatible manner) but instead of applying things it generates NetworkManager configuration in /run. Then an instance of NetworkManager can be run to apply the configuration, write a state file in /run, and exit. After the root is mounted and the real init runs the NetworkManager service, it can get an idea of what has been configured already by reading stuff from there. No guesswork needed.

The aim is to clean up the network boot process and reuse the broad network device support NetworkManager has. A nice side-advantage is that NetworkManager can do DHCP without dhclient with its internal (systemd-networkd based) DHCP client, that for some reason ends up being faster.

Thank you for explaining that! It now makes more sense as to why it is.

[caligula]

Yes, exactly this. Currently, the early boot network configuration is usually pretty hacky and distro-specific. Typically a bunch of shell scripts crunch the command line and configure (create, in case of bonds, vlans, etc.) the interfaces, bring them up and eventually start and stop dhclient. After the real init is run and NetworkManager is started, guesswork is needed to identify the connections activated on early boot (so that DHCP addresses are renewed and so on.)

The part that has now been merged parses the same command line arguments (in a compatible manner) but instead of applying things it generates NetworkManager configuration in /run. Then an instance of NetworkManager can be run to apply the configuration, write a state file in /run, and exit. After the root is mounted and the real init runs the NetworkManager service, it can get an idea of what has been configured already by reading stuff from there. No guesswork needed.

The aim is to clean up the network boot process and reuse the broad network device support NetworkManager has. A nice side-advantage is that NetworkManager can do DHCP without dhclient with its internal (systemd-networkd based) DHCP client, that for some reason ends up being faster.

I thought some distros already used systemd and systemd-networkd for this. NetworkManager only seems worth using if you need complex wireless set up, but those machines rarely do PXE boot, I'd guess.