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Bug 2073067 - drop internal "systemd" DHCPv4 client from NetworkManager
Summary: drop internal "systemd" DHCPv4 client from NetworkManager
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: NetworkManager
Version: 8.6
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Thomas Haller
QA Contact: Vladimir Benes
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2022-04-07 15:09 UTC by Thomas Haller
Modified: 2022-11-08 11:16 UTC (History)
8 users (show)

Fixed In Version: NetworkManager-1.39.2-1.el8
Doc Type: No Doc Update
Doc Text:
Clone Of:
Environment:
Last Closed: 2022-11-08 10:07:32 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-118272 0 None None None 2022-04-07 15:18:20 UTC
Red Hat Product Errata RHBA-2022:7680 0 None None None 2022-11-08 10:08:14 UTC
freedesktop.org Gitlab NetworkManager NetworkManager merge_requests 1188 0 None opened [th/systemd-no-dhcp4] drop internal systemd DHCPv4 client 2022-04-14 19:24:15 UTC
freedesktop.org Gitlab NetworkManager NetworkManager merge_requests 1191 0 None opened [th/replace-systemd-utils-1] replace usage of systemd code with our own code 2022-04-14 19:27:53 UTC

Description Thomas Haller 2022-04-07 15:09:08 UTC 
NetworkManager supports plugins for DHCP.

Historically, it used `[main].dhcp=dhclient` as the default plugin.

Many years ago, we started pulling in (copy+paste) systemd code, to get their DHCPv4, DHCPv6, LLDP and ACD/LLv4 libraries.

ACD/LLv4 got replaced in the meantime by nettools' n-acd.

Also, the default DHCP changed again to nettools' n-dhcp4.



Today, the systemd DHCPv4 client is still there, as undocumented plugin. You could enable it via `[main].dhcp=systemd`, but it was only kept as potential workaround if there are serious issues with the nettools (the new `internal` plugin).


By now, n-dhcp4 works fine. Let's remove systemd's DHCPv4 client.


Note that we also use systemd's DHCPv6 client. And there is no replacement for that yet. Also, in NetworkManager there is only one class (NMDhcpSystemd, subclassing NMDhcpClient) for both IPv4 and IPv6. So we cannot delete `NMDhcpSystemd` entirely. However, already in the past it was mad easy to rip out DHCPv4 while still using DHCPv6 client.


The problem with systemd's DHCP code is that it's mostly unused (only as undocumented plugin), and it's certainly not a good idea to start using it -- unless we would find a problem with n-dhcp4, where it would be kinda nice to have an alternative. But still. It also causes effort because we need to frequently update the forked code to not fall behind, that is always a bit of work. Dropping the DHCPv4 client, will make that less work (long term we want to drop all systemd code).
Comment 1 Thomas Haller 2022-04-20 20:05:47 UTC 
merged upstream.

We still use (of course) systemd's LLDP and DHCPv6 client. That is staying (for now).
We still internally use some other systemd API, that should be fixed soon (mr#1191 only fixed parts in this regard).

Still, systemd's DHCPv4 is gone. Moving to POST.
Comment 5 Vladimir Benes 2022-05-11 11:50:56 UTC 
everything tested and stays as before, verified
Comment 7 errata-xmlrpc 2022-11-08 10:07:32 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (NetworkManager bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:7680
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