[cloud] #14: Investigate systemd-networkd

[Fedora Cloud Trac Tickets]

#14: Investigate systemd-networkd
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 Reporter:  mattdm            |       Owner:  kushal
     Type:  task              |      Status:  accepted
 Priority:  normal            |   Milestone:  Fedora 21 (Alpha)
Component:  Cloud Base Image  |  Resolution:
 Keywords:  meeting           |
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Comment (by gholms):

 While networkd is certainly suited to simple network setups like those of
 most clouds, we need to keep the consequences of using it within the
 broader context of Fedora in mind.  Every other Fedora build, including
 Atomic, uses !NetworkManager to address the issues this feature aims to
 address, so choosing to use something else incurs costs that we should
 acknowledge:

 1. Network configuration will not be compatible with Fedora Workstation.
 As that is Fedora's development environment, this conflicts with the
 [https://fedoraproject.org/wiki/Cloud/Cloud_PRD Cloud PRD]'s goal of
 avoiding compatibility issues or surprises from differences in the
 environment.  Perhaps we could make this change in concert with
 Workstation.
 1. Network configuration will not be compatible with Fedora Server.  The
 cloudtoserver script could handle migration from networkd to NM, or the
 Server SIG could simply acknowledge that some fraction of Fedora Server
 users will wind up using networkd.
 1. Network configuration will not be compatible with Fedora Atomic.  This
 may not actually be a big deal, but shipping two cloud products that use
 incompatible means of configuring networking is somewhat surprising.
 1. This adds another tree of potential errors and breakage.  Using the
 same technology across multiple products benefits all of Fedora because
 they can share the testing burden.  This is unfamiliar code; we will need
 additional test cases to cover it and it will take some time and effort
 for people to spin up on it so they can debug it and provide feedback more
 useful than, "It doesn't work."
 1. This adds another tree of documentation since networkd can't use NM
 configuration files.

 We can address nearly all of these issues with a systemd
 [https://bugzilla.redhat.com/show_bug.cgi?id=1090090 generator] that reads
 the ifcfg-* files that NM uses.  People won't be able to use nmcli, but
 ifcfg files are still well-understood and what we configure NM to emit
 anyway.

 As for the additional testing burden, we probably just need to get QA buy-
 in.  Has anyone from QA chimed in on this feature yet?

 To be clear, I'm not against using networkd here, but the feature page is
 quite light on details like these that ought to be acknowledged.

-- 
Ticket URL: <https://fedorahosted.org/cloud/ticket/14#comment:42>
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