CentOS virt - Jan 2016 - CentOS 6 Virt SIG Xen 4.6 packages available in centos-virt-xen-testing

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.

To upgrade:

yum update --enablerepo=centos-virt-xen-testing

To install from scratch:

* Install centos-release-xen from centos-extras

yum install centos-release-xen

* Update to get the new kernel:

yum update

* Install the Xen packages from the centos-virt-xen-testing repo:

yum install --enablerepo=centos-virt-xen-testing xen

Keep in mind that there is still a bug in the upstream CentOS
new-kernel script which for some people consistently fails to add an
"initird" line to the Xen boot stanza.  Check /boot/grub/grub.conf;
the Xen stanza should look something like this:

title CentOS (3.18.21-17.el6.x86_64)
    root (hd0,0)
    kernel /xen.gz dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1
console=com1,tty loglvl=all guest_loglvl=all
    module /vmlinuz-3.18.21-17.el6.x86_64 ro
root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD
rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto
rd_LVM_LV=VolGroup/lv_root  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb
quiet
    module /initramfs-3.18.21-17.el6.x86_64.img


 -George

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.

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.


Peter

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

On 01/14/2016 06:57 PM, 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.
>
> To upgrade:
>
> yum update --enablerepo=centos-virt-xen-testing
>
> To install from scratch:
>
> * Install centos-release-xen from centos-extras
>
> yum install centos-release-xen
>
> * Update to get the new kernel:
>
> yum update
>
> * Install the Xen packages from the centos-virt-xen-testing repo:
>
> yum install --enablerepo=centos-virt-xen-testing xen
>
> Keep in mind that there is still a bug in the upstream CentOS
> new-kernel script which for some people consistently fails to add an
> "initird" line to the Xen boot stanza.  Check
/boot/grub/grub.conf;
> the Xen stanza should look something like this:
>
> title CentOS (3.18.21-17.el6.x86_64)
>      root (hd0,0)
>      kernel /xen.gz dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1
> console=com1,tty loglvl=all guest_loglvl=all
>      module /vmlinuz-3.18.21-17.el6.x86_64 ro
> root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD
> rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto
> rd_LVM_LV=VolGroup/lv_root  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb
> quiet
>      module /initramfs-3.18.21-17.el6.x86_64.img
>
>
>   -George
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> https://lists.centos.org/mailman/listinfo/centos-virt
Hello

     I've attempted to upgrade today to xen 4.6 ( because of something 
which seems to be a reincarnation of 
http://lists.xen.org/archives/html/xen-devel/2014-01/msg02259.html ) and 
I noticed that the new xen-runtime package tries to bring in a whole 
bunch of other packages:


Installing for dependencies:
  atk x86_64 1.30.0-1.el6 base 195 k
  avahi-libs x86_64 0.6.25-15.el6 base 55 k
  cairo x86_64 1.8.8-6.el6_6 base 309 k
  cups-libs x86_64 1:1.4.2-72.el6 base 321 k
  fontconfig x86_64 2.8.0-5.el6 base 186 k
  freetype x86_64 2.3.11-15.el6_6.1 base 361 k
  gdk-pixbuf2 x86_64 2.24.1-6.el6_7 updates 501 k
  gtk2 x86_64 2.24.23-6.el6 base 3.2 M
  hicolor-icon-theme noarch 0.11-1.1.el6 base 40 k
  jasper-libs x86_64 1.900.1-16.el6_6.3 base 137 k
  libXcomposite x86_64 0.4.3-4.el6 base 20 k
  libXcursor x86_64 1.1.14-2.1.el6 base 28 k
  libXft x86_64 2.3.1-2.el6 base 55 k
  libXi x86_64 1.7.2-2.2.el6 base 37 k
  libXinerama x86_64 1.1.3-2.1.el6 base 13 k
  libXrandr x86_64 1.4.1-2.1.el6 base 23 k
  libXrender x86_64 0.9.8-2.1.el6 base 24 k
  libthai x86_64 0.1.12-3.el6 base 183 k
  libtiff x86_64 3.9.4-10.el6_5 base 343 k
  pango x86_64 1.28.1-10.el6 base 351 k


Is this really needed ?

     wolfy

On Tue, Feb 2, 2016 at 2:47 PM, Manuel Wolfshant
<wolfy at nobugconsulting.ro> wrote:
> On 01/14/2016 06:57 PM, 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.
>>
>> To upgrade:
>>
>> yum update --enablerepo=centos-virt-xen-testing
>>
>> To install from scratch:
>>
>> * Install centos-release-xen from centos-extras
>>
>> yum install centos-release-xen
>>
>> * Update to get the new kernel:
>>
>> yum update
>>
>> * Install the Xen packages from the centos-virt-xen-testing repo:
>>
>> yum install --enablerepo=centos-virt-xen-testing xen
>>
>> Keep in mind that there is still a bug in the upstream CentOS
>> new-kernel script which for some people consistently fails to add an
>> "initird" line to the Xen boot stanza.  Check
/boot/grub/grub.conf;
>> the Xen stanza should look something like this:
>>
>> title CentOS (3.18.21-17.el6.x86_64)
>>      root (hd0,0)
>>      kernel /xen.gz dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1
>> console=com1,tty loglvl=all guest_loglvl=all
>>      module /vmlinuz-3.18.21-17.el6.x86_64 ro
>> root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD
>> rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto
>> rd_LVM_LV=VolGroup/lv_root  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb
>> quiet
>>      module /initramfs-3.18.21-17.el6.x86_64.img
>>
>>
>>   -George
>> _______________________________________________
>> CentOS-virt mailing list
>> CentOS-virt at centos.org
>> https://lists.centos.org/mailman/listinfo/centos-virt
>
> Hello
>
>     I've attempted to upgrade today to xen 4.6 ( because of something
which
> seems to be a reincarnation of
> http://lists.xen.org/archives/html/xen-devel/2014-01/msg02259.html ) and I
> noticed that the new xen-runtime package tries to bring in a whole bunch of
> other packages:
Those kinds of dependencies are automatically generated by rpmbuild
based on the linkages of the actual libraries.

I agree it would be nice to minimize the dependencies; but that would
take someone sitting down and figuring out which features / components
/ libraries / whatever were causing the dependencies, and either
disabling them or moving them to a separate package.  I don't have
time to do that at the moment; but I would be happy to help someone
else do so, and review pull requests to the xen package repos at
https://github.com/CentOS-virt7/xen.

 -George

On 02/02/2016 08:47 AM, Manuel Wolfshant wrote:
> On 01/14/2016 06:57 PM, 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.
>>
>> To upgrade:
>>
>> yum update --enablerepo=centos-virt-xen-testing
>>
>> To install from scratch:
>>
>> * Install centos-release-xen from centos-extras
>>
>> yum install centos-release-xen
>>
>> * Update to get the new kernel:
>>
>> yum update
>>
>> * Install the Xen packages from the centos-virt-xen-testing repo:
>>
>> yum install --enablerepo=centos-virt-xen-testing xen
>>
>> Keep in mind that there is still a bug in the upstream CentOS
>> new-kernel script which for some people consistently fails to add an
>> "initird" line to the Xen boot stanza.  Check
/boot/grub/grub.conf;
>> the Xen stanza should look something like this:
>>
>> title CentOS (3.18.21-17.el6.x86_64)
>>      root (hd0,0)
>>      kernel /xen.gz dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1
>> console=com1,tty loglvl=all guest_loglvl=all
>>      module /vmlinuz-3.18.21-17.el6.x86_64 ro
>> root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD
>> rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto
>> rd_LVM_LV=VolGroup/lv_root  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb
>> quiet
>>      module /initramfs-3.18.21-17.el6.x86_64.img
>>
>>
>>   -George
>> _______________________________________________
>> CentOS-virt mailing list
>> CentOS-virt at centos.org
>> https://lists.centos.org/mailman/listinfo/centos-virt
> Hello
> 
>     I've attempted to upgrade today to xen 4.6 ( because of something
> which seems to be a reincarnation of
> http://lists.xen.org/archives/html/xen-devel/2014-01/msg02259.html ) and
> I noticed that the new xen-runtime package tries to bring in a whole
> bunch of other packages:
> 
> 
> Installing for dependencies:
>  atk x86_64 1.30.0-1.el6 base 195 k
>  avahi-libs x86_64 0.6.25-15.el6 base 55 k
>  cairo x86_64 1.8.8-6.el6_6 base 309 k
>  cups-libs x86_64 1:1.4.2-72.el6 base 321 k
>  fontconfig x86_64 2.8.0-5.el6 base 186 k
>  freetype x86_64 2.3.11-15.el6_6.1 base 361 k
>  gdk-pixbuf2 x86_64 2.24.1-6.el6_7 updates 501 k
>  gtk2 x86_64 2.24.23-6.el6 base 3.2 M
>  hicolor-icon-theme noarch 0.11-1.1.el6 base 40 k
>  jasper-libs x86_64 1.900.1-16.el6_6.3 base 137 k
>  libXcomposite x86_64 0.4.3-4.el6 base 20 k
>  libXcursor x86_64 1.1.14-2.1.el6 base 28 k
>  libXft x86_64 2.3.1-2.el6 base 55 k
>  libXi x86_64 1.7.2-2.2.el6 base 37 k
>  libXinerama x86_64 1.1.3-2.1.el6 base 13 k
>  libXrandr x86_64 1.4.1-2.1.el6 base 23 k
>  libXrender x86_64 0.9.8-2.1.el6 base 24 k
>  libthai x86_64 0.1.12-3.el6 base 183 k
>  libtiff x86_64 3.9.4-10.el6_5 base 343 k
>  pango x86_64 1.28.1-10.el6 base 351 k
> 
> 
> Is this really needed ?
> 
The packages are built in mock (a clean buildroot with only required
packages) ... so only things called out as required by the spec file is
in the build root.

We can look at the build root log here:

http://bit.ly/1T4NGvy

Searching for this line in the log:

Getting requirements for xen-4.6.0-9.el6.src

It seems that SDL-devel, ghostscript, libX11-devel and gtk2-devel are
build requirements for xen-4.6 packages from that root.log .. so that
adds in all the X and gtk devel packages for linking against.

Looking at the spec file:

http://bit.ly/1SSRxu5

In Lines 105 to 108, those requires are there, so they are going to pull
in all the X and GNOME devel files that get linked against, so if those
spec file dependencies are requires, the links will be produced.

I don't see any way to get rid of those requires unless one redesigns
the packages.

Thanks,
Johnny Hughes





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