[CentOS-devel] VDO on CentOS Stream

Phil Perry

pperry at elrepo.org
Wed Sep 25 20:26:11 UTC 2019

On 25/09/2019 20:52, Andrew Walsh wrote:
> On Wed, Sep 25, 2019 at 3:47 PM Brian Stinson <brian at bstinson.com> wrote:
>> On Wed, Sep 25, 2019, at 14:39, Andrew Walsh wrote:
>>> Hello,
>>> First, let me express how excited I am by the news of the CentOS
>>> Stream offering.  I am really looking forward to how this works out in
>>> the long run.
>>> I am in the group that builds VDO, and it is currently delivered as a
>>> kmod in CentOS Stream, RHEL, and CentOS.  This requires that if the
>>> signatures of the symbols that VDO uses change from one kernel to the
>>> next, we may need to rebuild the package against the more recent
>>> kernel.
>>> The current version of kmod-kvdo ( delivered in
>>> CentOS Stream is the equivalent of the RHEL-8.0/CentOS-8.0 GA, while
>>> the version of the kernel (4.18.0-144.el8) is newer.  In the time
>>> between the kernel that kmod-kvdo was built against (4.18.0-72.el8)
>>> and the current kernel in CentOS Stream, the signatures have changed.
>>> As a result, the kernel modules delivered in the kmod-kvdo package
>>> cannot be loaded due to symbol mismatches (all device mapper related
>>> symbols that change periodically, from what I've experienced).
>>> I believe that a simple rebuild of kmod-kvdo- against
>>> kernel-4.18.0-144.el8 should be effective enough to get it working
>>> again.
>>> How can I help facilitate this rebuild now and/or moving forward?  I
>>> realize that things are still very much in motion and not fully
>>> implemented/decided at this point.
>>> Andy Walsh
>>> _______________________________________________
>>> CentOS-devel mailing list
>>> CentOS-devel at centos.org
>>> https://lists.centos.org/mailman/listinfo/centos-devel
>> Would a rebuild of kmod-vdo happen from these sources:
>> https://git.centos.org/rpms/vdo/tree/c8
> It would actually happen from
> https://git.centos.org/rpms/kmod-kvdo/tree/c8 since the vdo package
> just provides the user space libraries and utilities.
>> or are there changes needed?
> The only changes that should be needed (though I haven't tested it to
> be 100% certain), is to update the required kernel to make sure it
> builds against the proper kernel and also bump the Release field in
> the spec from 53 to 54 to get a new NVR.
> Change line 4
> %define spec_release 53
> To:
> %define spec_release 54
> Change line 9
> %define kmod_kernel_version 4.18.0-80.10.1.el8_0
> To:
> %define kmod_kernel_version 4.18.0-144.el8

I'm guessing you may want to add a t_functional test for each new kernel 
release to check if kmod-kvdo requires rebuilding before releasing the 
new kernel.

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