Comment # 3 on bug 1154092 from Eugen Block

(In reply to Robert Schweikert from comment #2)
> Is this the same image but with 2 different cloud.cfg files?

No, these are both log files written by cloud-init during the same boot process
of one instance. 

> The message is not related to using config drive, the code cannot determine
> in which configuration the network should be written out.
> 
> In order to find the proper rendering mechanism (the way the network
> configuration is written) for the network configuration code searches for
> specific commands to be available. For openSUSE and SLE, or in general to
> use the code that writes entries for "sysconfig" cloud-init looks for the
> 'ifup' and 'ifdown' commands.
> 
> In this case it appears as if these command are missing from the image being
> tested. This would trigger the error message shown in the initial comment.
> 
> It is known that the proper network writing code is selected for images with
> the 'ifup' and 'ifdown' commands included.
> 
> This suggests an issue with the image.

This image contains both commands:

leap15-1-cloudinit:~ # which ifup 
/sbin/ifup
leap15-1-cloudinit:~ # which ifdown 
/sbin/ifdown
leap15-1-cloudinit:~ # 


Running those commands manually after cloud-init has finished (unsuccessfully)
did work in a previous version of cloud-init, but it doesn't with Leap 15.1.