VMikhelson wrote:

> This is just one possible scenario which I still think worth
> documenting and sharing as the documentation on the upgrade paths and
> pitfalls from MicroFocus is not abundant to say the least.


I'm sorry you encountered so many issues. We do appreciate your
feedback though. Hopefully it will help others avoid some of the issues
you encountered.

The references you provided show how much has changed between
SLES11/SLES12 and between OES2015/OES2018. After the fact it's
difficult to know how things may have progressed had you adopted a
different approach.

Were you aware of this VMware knowledgebase article?
VMware support for guest operating system upgrade (2018695)
https://kb.vmware.com/s/article/2018695

> VMware does not support the installation of major update releases on
> an operating system as an upgrade in a virtual machine, such as
> Windows 7 to Windows 8 or RHEL 5.x to RHEL 6.0. VMware recommends the
> installation of a new major releases in a new virtual machine.


Just because something is unsupported does not guarantee you will
encounter issues but it is something to be aware of.

If the OS documentation states an update is supported, that definitely
offers a certain appeal. I have done many such updates without having
encountered any issues at all but now I wonder if that is really the
best approach.

When major changes have been introduced into a new version of an OS, a
vendor has to make some important decisions about how to deal with
upgrading components and features from previous versions.
- In most cases existing components are upgraded without any issues.
- in other cases the upgrade may cause incompatibility issues which
then have to be dealt with (systemd?).
- in some cases it is impractical to change what is already in place
(existing NSS32 pools?).

Even if no major issues are encountered during an upgrade, it is likely
that some compromises are being made behind the scenes. Because of
this, when installing a new major release, I now believe our first
choice should be a clean install of a new system along with a migration
and only consider an upgrade of an existing system if a migration is
impractical.



--
Kevin Boyle - Knowledge Partner
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