[ovirt-devel] [vdsm] Wrong default multipath configuration for EL6

[Nir Soffer]

----- Original Message -----
> From: "Patrick Hurrelmann" <patrick.hurrelmann at lobster.de>
> To: vdsm-devel at lists.fedorahosted.org, devel at ovirt.org
> Sent: Tuesday, July 29, 2014 4:43:36 PM
> Subject: [vdsm] Wrong default multipath configuration for EL6
> 
> Hi all,
> 
> after suffering from boot-failures after kernel-updates on my EL6 hosts
> (the ones that san boot via iscsi), I finally managed to locate the root
> cause of the problem: the default values as set by vdsm are incorrect
> for EL6 and prohibit a successful iscsi boot (the faulty multipath.conf
>  gets embedded in the new initrd on a kernel update). Additionally the
> following errors are repeatedly logged on all my hosts (device ids may
> vary) with the default vdsm multipath config:
> 
> device-mapper: table: 253:5: multipath: error getting device
> device-mapper: ioctl: error adding target to table
> device-mapper: table: 253:5: multipath: error getting device
> device-mapper: ioctl: error adding target to table
> 
> And it all boils down to the default value set for option getuid_callout
> in multipath.conf. Vdsm sets it to the following:
> 
> getuid_callout  "/sbin/scsi_id --whitelisted --replace-whitespace
> --device=/dev/%n"
> 
> According to the man-page and other docu the default value on EL6 is
> "/lib/udev/scsi_id --whitelisted --device=/dev/%n". Although the binary
> /sbin/scsi_id is a valid link to the target /lib/udev/scsi_id, the link
> itself (/sbin/scsi_id) is _not_ included in the generated initrd. The
> binary /lib/udev/scsi_id is indeed included and changing the default
> config to use /lib/udev/scsi_id instead does make it all work again.
> iscsi boot (after regenerating the initrd, as the multipath.conf is
> embedded) is back to good and the previously logged device-mapper errors
> are gone, too.
> 
> Can someone please verify this and and apply the easy (attached) patch?

Thanks Patrick!

I'll look into this.

Would you open a bug for this issue, to help us track this issue?

> 
> --- multipath.py.orig	2014-07-29 15:24:37.643839169 +0200
> +++ multipath.py	2014-07-29 15:25:06.823840362 +0200
> @@ -88,9 +88,8 @@
>  log = logging.getLogger("Storage.Multipath")
> 
>  _scsi_id = utils.CommandPath("scsi_id",
> -                             "/sbin/scsi_id",  # EL6
>                               "/usr/lib/udev/scsi_id",  # Fedora
> -                             "/lib/udev/scsi_id",  # Ubuntu
> +                             "/lib/udev/scsi_id",  # EL6, Ubuntu
>                               )
> 
> 
> 
> Thanks a lot and best regards
> Patrick
> 
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