[CentOS-virt] CentOS 6 Virt SIG Xen 4.6 packages available in centos-virt-xen-testing

Alvin Starr

alvin at netvel.net
Thu Jan 21 16:17:55 UTC 2016


My comment was targeted more at naming than support.

I appreciate that there are vanishingly few resources to throw at support.

I am glad to see any xen support for C7 and am thankful of all those who 
are putting in time to make things happen.
I try to help out when I can but it is all too infrequently.


On 01/21/2016 10:29 AM, Johnny Hughes wrote:
> This is a community SIG .. and xenproject.org does NOT release XSAs for
> 4.2.  The goal of Xen4centOS was to use an upstream LTS kernel and
> update those as required to stay on an LTS.  Also to do every second
> point release of xen (ie, 4.2, 4.4, 4.6).  All so we are longer term
> than upstream, BUT we have supported code from upstream.
>
> So, the goal is to use supported code for the longest amount of time the
> upsreams support them.  For xenproject.org .. they support the two
> newest releases.  For kernel.org, they do a new kernel LTS about every 2
> years.
>
> We don't have 5000 engineers to maintain community SIGs like they
> maintain the distro.  We have to have supported code from upstream projects.
>
> On 01/21/2016 07:46 AM, Alvin Starr wrote:
>> Its my impression that as a general rule from RH once some software has
>> been released into a major release any further release of that software
>> does not change major version or fundamental features..
>>
>> For C6 I would argue Xen 4.2 should stay packaged as xen and Xen 4.4 be
>> packaged as xen44 ...
>> I do not believe that Xen has been released for C7 yet so what ever
>> package version is released should be xen and others should be xen4x.
>>
>> It provides consistency for those who expect it and upgrading for those
>> who need it.
>>
>> Looking at a C7 with epel added.
>> I can see python, python2 and python3.
>>
>> On the other hand If your picking xen up from
>> http://someplace.org/riskey-development/xen.repo then your getting what
>> you ask for.
>>
>>
>> On 01/21/2016 08:09 AM, President wrote:
>>> RE: [CentOS-virt] CentOS 6 Virt SIG Xen 4.6 packages available in
>>> centos-virt-xen-testing
>>>
>>> My .02 is to stay the course.  As a server admin, I want to be able
>>> to type things like:
>>>
>>>
>>> yum upgrade php
>>>
>>>      not
>>>
>>> yum upgrade php55-epel-rpmforge-fancy-package
>>>
>>>
>>> Having to remember all the idiosyncrasies of a system is what causes
>>> some type of major failure in the future whenever (1) you forget
>>> something or (2) someone else has to pick up the box to adminster.
>>>
>>>
>>>
>>> --
>>>
>>> Craig Thompson, President
>>>
>>> Caldwell Global Communications, Inc.
>>>
>>> +1 (423) 559-5465
>>>
>>> caldwellglobal.com
>>>
>>>
>>>      -----Original message-----
>>>      *From:* George Dunlap <dunlapg at umich.edu>
>>>      *Sent:* Thursday 21st January 2016 7:32
>>>      *To:* Discussion about the virtualization on CentOS
>>>      <centos-virt at centos.org>
>>>      *Subject:* Re: [CentOS-virt] CentOS 6 Virt SIG Xen 4.6 packages
>>>      available in centos-virt-xen-testing
>>>
>>>      On Thu, Jan 21, 2016 at 12:01 PM, Peter <peter at pajamian.dhs.org> wrote:
>>>      > On 15/01/16 05:57, George Dunlap wrote:
>>>      >> As mentioned yesterday, Xen 4.6 packages are now available for
>>>      >> testing.  These also include an update to libvirt 1.3.0, in line with
>>>      >> what's available for CentOS 7.  Please test, particularly the upgrade
>>>      >> if you can, and report any problems here.
>>>      >
>>>      > Per conversation in IRC, Xen 4.6 no longer includes xend and therefore
>>>      > no longer has the "xm" command.  This is problematic for people who may
>>>      > be using xm in various scripts on their host (such as home-brewed backup
>>>      > scripts).
>>>      >
>>>      > I think it's a bad idea to break this functionality without warning by
>>>      > allowing a simple "yum update" to remove it.  You will take a lot of
>>>      > people by surprise and cause such scripts to stop working, if people are
>>>      > running yum cron the situation becomes even worse.
>>>
>>>      Thanks, PJ, for your input.
>>>
>>>      Just to be clear:
>>>
>>>      1. In the Xen 4.4 packages (first released October 2014), xend was
>>>      disabled by default; so anyone using xend at the moment has already
>>>      manually intervened to enable deprecated functionality
>>>
>>>      2. In 4.4, the first time xm was executed, it printed this warning:
>>>      ---
>>>      xend is deprecated and scheduled for removal. Please migrate to another
>>>      toolstack ASAP.
>>>
>>>      See http://wiki.xen.org/wiki/Choice_of_Toolstacks for information on
>>>      other alternatives, including xl which is designed to be a drop in
>>>      replacement for xm (http://wiki.xen.org/wiki/XL).
>>>      ---
>>>
>>>      3. ...and on every subsequent invocation, it printed this warning:
>>>      "WARNING: xend/xm is deprecated"
>>>
>>>      I think this constitutes "warning" that the functionality was going to
>>>      break at some point. :-)
>>>
>>>      Also, in most cases "s/xm/xl/g;" Just Works; most people have reported
>>>      that changing from xm -> xl was pretty painless.  So this isn't like
>>>      upgrading from Python 2 to Python 3 (or QT 4 to 5, or...).
>>>
>>>      > I think that due to this lack of backwards compatibility with Xen 4.4
>>>      > and earlier versions it would be a good idea to not force the upgrade on
>>>      > people who are not wary of it.  I propose that the new packages carry
>>>      > the name "xen46" and they purposefully conflict with the old "xen"
>>>      > packages.  That will require people to take positive action to do the
>>>      > upgrade and hence avoid breaking systems unintentionally.
>>>
>>>      This would avoid breaking things for people still using xm, which
>>>      certainly has some value.  However it has some costs:
>>>
>>>      * The packages between C6 and C7 will now be slightly different,
>>>      increasing the maintenance burden.  This is not only in the spec file,
>>>      but also in all the associated scripting machinery for managing
>>>      packages in the CBS and smoke-testing packages before pushing them
>>>      publicly.
>>>
>>>      * Instructions for installing Xen are now differend between C6 and C7,
>>>      and slightly more complicated, as they have to explain about Xen 4.6
>>>      vs alternatives.
>>>
>>>      * Users who have heeded the warning and switched to xl will have to
>>>      make an extra effort to switch to Xen 4.6.  If they don't follow
>>>      centos-virt, they may not notice that there's a new package to upgrade
>>>      to.
>>>
>>>      I'm a developer, not a server admin, so I can't gauge how important
>>>      this issue is.  Before making such a change, I'd like to hear opinions
>>>      from other people in the community about how important (or not) it is
>>>      to avoid breaking xm, given the ample warning (>1 year) users have
>>>      had.
>>>
>>>      On the other hand, explicitly moving to a "xen${VER}" (both for C6 and
>>>      C7) would make it simpler for people to step up and maintain older
>>>      versions in parallel if anybody wanted to do so.
>>>
>>>      Thanks again, Peter, for bringing this up.
>>>
>>>      Peace,
>>>       -George
>>>      _______________________________________________
>>>      CentOS-virt mailing list
>>>      CentOS-virt at centos.org
>>>      https://lists.centos.org/mailman/listinfo/centos-virt
>>>
>>>
>>>
>>> _______________________________________________
>>> CentOS-virt mailing list
>>> CentOS-virt at centos.org
>>> https://lists.centos.org/mailman/listinfo/centos-virt
>>
>> -- 
>> Alvin Starr                   ||   voice: (905)513-7688
>> Netvel Inc.                   ||   Cell:  (416)806-0133
>> alvin at netvel.net              ||
>>
>>
>>
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>
>
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-- 
Alvin Starr                   ||   voice: (905)513-7688
Netvel Inc.                   ||   Cell:  (416)806-0133
alvin at netvel.net              ||

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