Comment # 20 on bug 1223167 from Stefan Hundhammer

But in your case, it doesn't even get as far as trying to mount anything from
the existing system on the disk: It already fails when reading the content of
the installation medium.

I just tried on an existing VM, and with that same installation ISO

  openSUSE-Leap-15.5-DVD-x86_64-Build491.1-Media.iso

4413456384 bytes, sha256sum

  53bcbcb82361c5261c9d0994ab0f94101bf28e61c06fe12d320984601be35a8f

(just like downloaded from here https://get.opensuse.org/leap/15.5/#download)

I get

>> 04:40:13 <1> [Ruby] y2packager/installation_medium.rb(read):74
>>   Base Products: [#<Y2Packager::RepoProductSpec:0x000056530533c8c8
>>   @name="Leap",
>>   @version="15.5",
>>   @arch="x86_64",
>>   @display_name="openSUSE Leap 15.5",
>>   @order=nil,
>>   @base=true,
>>   @selected=false,
>>   @register_target="",
>>   @depends_on=[],
>>   @dir="/AP_0x67lFfB",
>>   @media_name="/AP_0x67lFfB",
>>   @description="openSUSE Leap 15.5.">]


where you get

>> 11:27:12 <1> [Ruby] y2packager/installation_medium.rb(read):74 Base Products: []

and that's where it starts going downhill. It doesn't even was as far as trying
to mount any partitions from your hard disk(s) to probe what existing systems
there are on your disks to upgrade from.

Just as in your y2log, the name of the on-DVD repository is

>>  04:40:07 <1> [Pkg] Source_Download.cc(SourceProvideFileCommon):77
>>    Downloading file
>>    /repodata/df6fa38c088f2cbd6f718b30d09ce24654b85a0ca5152437ae8c8d9b60473b90-primary.xml.gz
>>    from repository 0, medium 1


But for some reason, yours does not contain any base product.

Please download the installation ISO again (and of course check the checksum),
and please use a USB stick this time to boot and upgrade from.

Maybe your DVD drive isn't as reliable anymore as it used to be. If it's
anything like mine, it might not see much use these days, which might make it
unreliable.


I'd appreciate if you'd try the same procedure again until the point where you
see an existing partition to choose the system to upgrade. If this time it gets
that far, it was an issue with your DVD drive.

Anyway, at that point you'll have to stop because then the ZFS problem will
start to kick in; a successful upgrade will in your case only work when booting
the old system and then using the zypper method that Lukas mentioned in comment
#18.