missing description for migration of ifup/down scripts

[Hadmut Danisch]

Hi,

I'm still struggling with the migration of ubuntu 16.04 -> 18.04 due to the invention of netplan.

I have several use cases where lots of scripts in /etc/network/if-{up,down,...}.d need to be run, e.g. firewalling rules, starting particular daemons, etc.

I've spent several days of search for description about how to migrate those up/down scripts, could not find any, but lots of reports of other people having similar problems. Some recommend strange and error prone combinations of udev and systemd, other recommend netword-dispatcher (which I tried and it doesn't work), still others say that if you want things to run you'll need to reinstall ifupdown.

To the best of my current knowledge netplan seems to be broken by design or at least far from production ready, as if the requirements of starting and stopping jobs for a particular interface had just been completely forgotten (or at least been forgotten to mention in the documentation).

So what is the netplan's way of taking interfaces up and down (on request, and not just at boot time) and to start and stop services for these interfaces?

[Daniel Axtens (daxtens)]

Hi,

I'm sorry to hear that you have ad a bad experience with netplan.

The usual answer to this is that you have 3 options.

The first and most preferred option is to use networkd-dispatcher. There is some documentation, including examples, at https://netplan.io/faq#use-pre-up-post-up-etc-hook-scripts This will work for starting/stopping jobs when an interface goes up and down, not just at boot.

The second option is to use a systemd unit file. These are more flexible than networkd-dispatcher in that they can run at a wider range of times. There are lots of examples of this on the internet.

Lastly, you can purge netplan.io and install ifupdown and go back to the way things were if you wish.

Hope this helps, please let me know if there's anything netplan related where you need further information.

Regards,
Daniel

[Hadmut Danisch (hadmut)]

1) Giving recommendations in a bug ticket is not a fix for a missing documentation.

2) I've tried that networkd-dispatcher, and just had more trouble: See #1775559 and #1775581 It just doesn't recognize changes in virtual bridge interfaces.

3) the whole bunch of systemd/dispatcher/netplan is a heap of poorly (if at all) documented, overcomplexed, intransparent, unmaintanable, and error prone bad software, far from beeing production ready, and should have never made it's way into production software in it's current state.

4) Unbuntu is currently not even able to cope with dependencies. I have lxd machines connected to a virtual bridge managed with netplan, and they simply don't work after boot, since Ubuntu is unable to run jobs in the right order and thus starts dnsmasq too early when the bridge does not yet exist. I have to run systemctl restart dnsmasq manually to get things running. Fixing the dependencies and execution order is considered as 'too complicated' (see #1777094 ), so ubuntu has installed a system that

a) does not work properly
b) is too complicated to be fixed
c) is not documented sufficiently

Once upon a time ubuntu was rock-stable and reliable. Now it's unreliable, unmaintenable, unfixable.

[Launchpad Janitor (janitor)]

[Expired for netplan because there has been no activity for 60 days.]