Mailinglist Archive: opensuse-features (226 mails)

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[openFATE 305634] Debian-like dist-upgrade live system full version upgrade
  • From: fate_noreply@xxxxxxx
  • Date: Wed, 4 Feb 2009 22:38:45 +0100 (CET)
  • Message-id: <feature-305634-63@xxxxxxxxxxxxxx>
Feature changed by: Federico Lucifredi (flucifredi)
Feature #305634, revision 63
Title: Debian-like dist-upgrade live system full version upgrade

openSUSE-11.2: Evaluation
Priority
Requester: Mandatory

Info Provider: Robert Davies (robopensuse)
Requested by: Federico Lucifredi (flucifredi)
Partner organization: openSUSE.org

Description:
With the 11.2 cycle, we want to offer users the ability to perform a
live system upgrade in the manner of Debian's dist-upgrade.
For the purpose of this cycle, we want to support dist-upgrade from the
previous version (11.1) only, as this is a sufficiently complicated
problem as is.
From the user's view, the difference is between being able to update
the system incrementally within the given version or service pack
running, to being ble to migrate with a system command ("zypper dup" or
similar) to a higher version altogether.
In the Debian experience, the set of base distributions is not
necessarily limited, but it has been Ubuntu's practice to define what
starting points other than "release n-1" are allowed (for instance, all
LTS versions are purported to be able to "apt dist-upgrade" to the top
of the line, although I have heard of problems trying to jump two years
- 6.06->8.10 - in a fell swoop in this manner :-).
In the openSUSE scope, we should aim to be able to "dup" between
incremental versions, starting from 11.1 to 11.2, and later 11.x to
12.0.

Business case (Partner benefit):
openSUSE.org: With the introduction of the Zypper stack to SLE, we
finally reached the state of a featureful (which YOU was not) and fast,
reliable (which ZLM was not) update stack in the platform.
For enterprise use, some tweaks are still desirable (changelogs,
rollback, ...) which we are looking at, as well as improvements on the
Enterprise management front, which we are working on with our SRM
colleagues.
The only really significant competitive feature we are missing at this
point is the Debian/Ubuntu dist-upgrade functionality, which has a
powerful psychological impact at the Enterprise level and a much more
tangible impact at the small user / single user level: many with no IT
department do use Ubuntu these days on the basis that "chasing" Fedora
and openSUSE along the six-month upgrade cycle is too much for them,
and feel they can save time on Ubuntu with the combination of dist-
upgrade and the longer LTS cycle.
The rationale for pursuing this is to revoke the special status of
coolness this functionality gives Ubuntu, and to terminate the negative
influence that may have on our SLE sales (from the expert's personal
opinion, the preference then easily spills into purchasing).

Discussion:
#1: Federico Lucifredi (flucifredi) (2009-01-07 20:42:15)
This is the #1 feature in the systems management scope for 11.2 - I
have no doubt it will be fun :-)

#4: Klaus Kämpf (kwk) (2009-01-09 11:32:53)
Passing to mls for technical evaluation (solver + autobuild)

#5: Michael Schröder (mlschroe) (2009-01-09 12:48:10)
Any hint on what features are currently missing?

#6: Klaus Kämpf (kwk) (2009-01-09 13:30:57) (reply to #5)
From the top of my head:
How to handle
* Library ABI changes (e.g. major gcc/g++ upgrades) ?
* Core package changes (e.g. devs.rpm to udev) ?
* Kernel changes (if application/deamons need a specific kernel abi,
dbus comes into mind) ?
* Failure handling (network breakdown, package update errors, ...) ?
* Booting of the new kernel ?


#7: Michael Schröder (mlschroe) (2009-01-09 14:45:09) (reply to #6)
And debian does this in some way?

#8: Robert Davies (robopensuse) (2009-01-17 12:43:42) (reply to #7)
The distupgrade feature differs from changing source list and doing
upgrade, so some utility process could be started. They may require
some documented procedure to be followed, for "tough" changes. But ABI
change, how long since ELF/glibc was introduced? C++ ABI ought not be
relevant for upgrade process, they are "just" applications and libaries
to be updated. Failure handling - you are told to back up your system
first, it is "best effort" not guaranteed. The less you have installed
the more likely it is to succeed. Debian offer choice of kernels, this
may "punt" the problem to a user controlled install and select from
GRUB menu. Debian have apt-cache possibility, to create central pool of
packages, to decrease liklihood of network troubles, as well as huge
number CD and DVD iso's.

#9: Thorsten Kukuk (kukuk) (2009-01-17 15:24:35) (reply to #8)
The glibc internal ABI changes frequently. Means, running applications
will continue to use the old glibc with the old ABI, but installed are
already the new plugins => running applications can crash.

#12: Robert Davies (robopensuse) (2009-01-31 15:36:30) (reply to #9)
But your upgrade tools are buggy if they are built to rely on
"plugins". If you try to dist upgrade a live system within GUI, with
all software running, and no breakage, you aim impossibly high. The
point is, Debian have had very positive user comments for years about
this feature, despite there being many caveats and no guarantee of
success.

#13: Robert Davies (robopensuse) (2009-01-31 15:42:55) (reply to #12)
That wasn't clear. The upgrade tools are built so they won't suffer
from changes. It is reasonable to ask user to not be running uncessary
applications during a dist upgrade.

#16: Duncan Mac-Vicar (dmacvicar) (2009-02-02 10:19:55) (reply to #12)
Thorsten is talking about general applications. Not plugins.

#10: Cristian Rodríguez (elvigia) (2009-01-20 03:36:38) (reply to #8)
ABI is important during the upgrade process, I have seen applications
crashing if you upgrade running a desktop enviroment, however we need
to worry more about other stuff first IMHO.

#11: Duncan Mac-Vicar (dmacvicar) (2009-01-29 16:51:48)
I think the "Debian" part of the title is missleading if what we want
is just to support dup officially.
I would like to see a list from some "Debian expert" on how to Debian
handles the issues Klaus described above. Appart of the network failure
(included in another feature: commit) I ignore (and did not experience
during my old Debian times) if Debian does anything special on dist-
upgrade which give them the honour to name this feature "Debian like".
Otherwise this feature should be closed as "done", (or just waiting for
the commit refactoring).
Federico, as you named the feature "Debian-like", It would be helpful
to know, appart of the download-first feature, what are you missing
from Debian so we can reach that point.

#14: Robert Davies (robopensuse) (2009-01-31 15:54:26) (reply to #11)
Technically you may be right, but that does not solve the perceived
problem for end users who want a very well tested, and documented
upgrade path. 11.1 shipped with release notes without solutions for
problems folk hit (eg) PAM stuff).

#15: Duncan Mac-Vicar (dmacvicar) (2009-02-02 10:22:12) (reply to #14)
Exactly, but if we don't know what specific problems are we hitting
during distupgrade the feature has no real work and specific problems
can be tracked as bugs.
FATE is not a place for "make this better" without concrete
requirements or "make an unfalible distupgrade".
If requester, prjmgr, or pm expects anything to be done in the area, we
need at least:
* A list of problems we hit during dist upgrade (I am aware of one
specific, which is download-install sequence if network goes down)
* The scope. As you mention, asking to close every application (or
service) is not much to ask. Therefore the scope has to be set, because
if the scope is "distupgrade and glbc upgrade while oracle process
hospital monitoring equipment transactions" then this is a very
expensive feature.


#17: Duncan Mac-Vicar (dmacvicar) (2009-02-02 10:21:02) (reply to #14)
btw, can you describe in technical detail the pam upgrade problem so we
can document it?

#18: Thorsten Kukuk (kukuk) (2009-02-02 10:26:58) (reply to #17)
Yes, the PAM maintainers would like to know more details, too.

#19: Robert Davies (robopensuse) (2009-02-02 13:45:04) (reply to #18)
There were a number of different forum poster's hitting it, just after
11.1 released (I think due to zypper dup not YaST upgrade and therefore
unreported to BugZilla). It is not something I had, because I did fresh
installs. Interestingly though I have used Debian less, I have done
several dist-upgrade's, simply because it is expected to work well. So
it is a mistake to focus on specific tech issues alone. This problem is
also about expectations and user perceptions. Announcing "support" for
dist upgrade and appealing for test, so work rounds can be found, for
release notes at time matters to.

#21: Cristian Rodríguez (elvigia) (2009-02-02 15:29:32) (reply to #19)
as you failed to elaborate on the problem, I will.. Some people end
with broken /etc/pam.d/login they have the following line
session required pam_resmgr.so but that module is gone, and rpm
upgrade does not remove that line (probably because that file has been
modified)

#24: JP Rosevear (jproseve) (2009-02-02 10:15:19) (reply to #21)
Isn't that simply a packaging problem?

#25: Klaus Kämpf (kwk) (2009-02-02 19:42:45) (reply to #24)
In this case, it looks like a packaging problem, indeed.
However, we had more complicated upgrade tasks in the past, like
dropping devs.rpm and running udev instead.
See Removing devs.rpm
(http://en.opensuse.org/Software_Management/Upgrade/Devs_Rpm) for a
discussion of the problem.

#26: Klaus Kämpf (kwk) (2009-02-02 19:43:24) (reply to #21)
Whats the bug number for this problem ?

#20: Robert Davies (robopensuse) (2009-02-02 14:48:34)
On Scope, here are the Release Notes for Lenny -
http://www.uk.debian.org/releases/testing/amd64/release-notes/ 4.1.4 -
Prepare a safe environment for the upgrade - text mode or via ssh
login, Article on how to go from Etch to Lenny -
http://www.debianadmin.com/howto-upgrade-from-debian-etch-40-to-lenny-50.html


+ #27: Federico Lucifredi (flucifredi) (2009-02-04 15:32:01) (reply to
+ #20)
+ this is very helpful, we should look at the bumps that Debian hits while
+ doing this.
+ On a separate note, just tried to "yum upgrade" frlom RHEL 5.2 to RHEL
+ 5.3, and it went without a hitch. There may be something to be gathered
+ from Fedora as well here.

#22: Manuel Trujillo (toomany) (2009-02-02 15:44:44)
I think this is a really helpful characteristic, because a lot of
people like me, use openSUSE as server, and is a true hell to upgrade
servers in any datacenter, at kilometers off distance. I hope this
feature will be a reallity in the next 11.2.

#23: Duncan Mac-Vicar (dmacvicar) (2009-02-02 15:46:27) (reply to #22)
Please, if you just want to express your favorites, use the voting
feature. Comments is for discussion around solving the problem itself.



--
openSUSE Feature:
https://features.opensuse.org/305634

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