replacement of isc-dhcp-client with with systemd-networkd for dhclient needs integration

Packages which depend on isc-dhcp-client do so because they invoke the dhcp client directly for their own purposes. This will not change; systemd-networkd does not expose a dhcp client for direct use by other callers.

madwimax is a network driver package (not a network manager) that invokes dhclient directly on events. That looks like something that should be integrated with systemd-networkd somehow.

avahi-autoipd's dhclient hook exists for stopping and restarting the avahi-autoipd daemon while other dhclient hooks are running. I don't know why exactly it does this but I don't think there's going to be a relevant equivalent in systemd-networkd.

resolvconf is being dropped at the same time as ifupdown/isc-dhcp-client; there is no need to integrate it with systemd-networkd.
openresolv is an alternative implementation of resolvconf which has never been used in Ubuntu.

"I don't know.... I don't think.." doesnt really seem like valid justification for marking Invalid on avahi. I went looking a bit further. I'm not exactly sure why it ties into dhcp hooks, but it also ties into ifupdown hooks.

Should I raise another of these bugs for programs that ship ifupdown hooks ?
  /etc/network/if-{up,down}.d/*
?

Anything that did use those will have to be transitioned.

On Tue, Sep 19, 2017 at 01:09:24PM -0000, Scott Moser wrote:
> "I don't know.... I don't think.." doesnt really seem like valid
> justification for marking Invalid on avahi. I went looking a bit
> further. I'm not exactly sure why it ties into dhcp hooks, but it also
> ties into ifupdown hooks.

Ok, so alternate rationale: avahi-autoipd is a service that is primarily of
interest to mobile client systems, not to servers. The ifupdown->networkd
transition only affects servers. On client systems, we will continue to use
NetworkManager, which for the past 9 years has not been running the dhclient
hooks:

  https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/293139

And no one has complained in that time about misbehavior of avahi as a
result of these particular hooks not being run. Therefore, whatever the
reason these undocumented upstream hooks were added, I don't believe they
matter for the ifupdown->systemd transition.

If you prefer to express this as 'wontfix' or 'triaged'+'wishlist', I don't
mind. But in terms of prioritization, I don't consider it important to
follow through any further on the avahi dhclient hooks.

> Should I raise another of these bugs for programs that ship ifupdown hooks ?
> /etc/network/if-{up,down}.d/*

I think that's reasonable. But please note that networkd simply does not
support these kinds of hooks today (in particular it does not support
if-pre-up.d and if-down.d because these hooks must block networkd; you can
implement if-up.d and if-post-down.d by running /after/ the network events).
The decision to migrate to networkd has been taken in full knowledge that,
at least initially, there would be regressions in these kinds of
integrations.

I opened bug 1718227. for packages that ship if-up.d or if-down.d scripts.

On Tue, Sep 19, 2017 at 2:18 PM, Steve Langasek <
<email address hidden>> wrote:

> On Tue, Sep 19, 2017 at 01:09:24PM -0000, Scott Moser wrote:
> > "I don't know.... I don't think.." doesnt really seem like valid
> > justification for marking Invalid on avahi. I went looking a bit
> > further. I'm not exactly sure why it ties into dhcp hooks, but it also
> > ties into ifupdown hooks.
>
> Ok, so alternate rationale: avahi-autoipd is a service that is primarily
> of
> interest to mobile client systems, not to servers. The ifupdown->networkd
> transition only affects servers. On client systems, we will continue to
> use
> NetworkManager, which for the past 9 years has not been running the
> dhclient
> hooks:
>
> https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/293139
>
> And no one has complained in that time about misbehavior of avahi as a
> result of these particular hooks not being run. Therefore, whatever the
> reason these undocumented upstream hooks were added, I don't believe they
> matter for the ifupdown->systemd transition.
>
> If you prefer to express this as 'wontfix' or 'triaged'+'wishlist', I don't
> mind. But in terms of prioritization, I don't consider it important to
> follow through any further on the avahi dhclient hooks.
>
> > Should I raise another of these bugs for programs that ship ifupdown
> hooks ?
> > /etc/network/if-{up,down}.d/*
>
> I think that's reasonable. But please note that networkd simply does not
> support these kinds of hooks today (in particular it does not support
> if-pre-up.d and if-down.d because these hooks must block networkd; you can
> implement if-up.d and if-post-down.d by running /after/ the network
> events).
> The decision to migrate to networkd has been taken in full knowledge that,
> at least initially, there would be regressions in these kinds of
> integrations.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1717983
>
> Title:
> replacement of isc-dhcp-client with with systemd-networkd for dhclient
> needs integration
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/
> 1717983/+subscriptions
>

I believe all of the cloud-init is covered by https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1718029 and addressed by https://code.launchpad.net/~xnox/cloud-init/+git/cloud-init/+merge/331642

This bug was fixed in the package ntp - 1:4.2.8p10+dfsg-5ubuntu3

---------------
ntp (1:4.2.8p10+dfsg-5ubuntu3) artful; urgency=medium

  * d/ntp.dhcp add support for parsing systemd networkd lease files LP:
    #1717983

 -- Dimitri John Ledkov <email address hidden> Tue, 03 Oct 2017 01:54:33 +0100

controlaula does not exist in Ubuntu beyond artful. So invalid for bionic, and wontfix for artful.

ddclient wants to send updated IP address information to the dyndns server when a new IP address is received from DHCP.

This should be supplemented with a networkd-dispatcher routable.d hook.

"high" for ddclient wrt the importance of the hook to the operation of the package.

python3-maas-provisioningserver calls dhclient directly in order to do network discovery. This does not need replaced with networkd integration.

samba-common's dhclient hook needs porting. Setting to 'medium' as this only affects dhcp-provided netbios nameservers and netbios scope, which are relatively uncommon options.

Per /usr/share/sendmail/dynamic, /etc/dhcp3/dhclient-exit-hooks.d/sendmail is considered deprecated in favor of /etc/network/if-{up,post-down}.d/sendmail. Therefore for sendmail's purposes, this is a duplicate of LP: #1718227.

ubuntu-meta retains a dependency on isc-dhcp-client for use in initramfs (via initramfs-tools integration), and application which will not be replaced by networkd for the foreseeable future.

Based on https://bugs.launchpad.net/ubuntu/+source/ubuntu-meta/+bug/1717983/comments/9, marking this done for cloud-init.