How to determine "internal" disk in a Cobbler snippet/kickstart

[Parthasarathy, Balaji (BCS, Cupertino, USA)]

Hi,
When I install a system using Cobbler using kickstart/snippet, I want to only do the
partitioning of

1.      Internal only disk

2.      Only one disk, if multiple exist

3.      Handle RAID/non-RAID scenarios

Is there a good/reliable way in Linux (RHEL and Fedora specifically) to determine #1?
Since we are in the installation environment, some commands (like lsscsi) aren't
available. Here's what I'm using in my snippet currently.

======== BEGIN SNIPPET ============
# Look for any 'scsi' or 'cciss' device; weed out output with partitions
of those
# devices (part) and cd/dvd devices (sr); grab the first line of the remaining output.
# Assumption is first scsi device is "internal" disk. We want to partition only
# the first internal disk.
ls_output=\$(ls -l /dev/disk/by-path/pci* | grep -i -e scsi -e cciss | grep -v -i -e part
-e sr | head -n 1)

# If we did not get any proper data for disk devices, just let anaconda do auto
partitioning
# and use all/whatever disks anaconda finds, rather than throw an error.
if [[ -z "$ls_output" ]]
then
  ks_partition_cmd=""
else
  # NOTE: we are parsing a output that looks like this:
  #     lrwxrwxrwx. 1 root root 9 Jun 18 13:01
/dev/disk/by-path/pci-0000:0c:00.0-scsi-0:0:0:1 -> ../../sda
  device_symlink=\$(echo \$ls_output | awk '{print \$11}')

  if [[ ! -z \$(echo \$device_symlink | grep -i sd) ]]
  then
    # The first internal disk is a non-RAID disk.
    # Remove the "../../" prefix in "../../sda"
    first_internal_disk_name=\${device_symlink\#\#*/}
  else
    # The first internal disk is a RAID disk.
    # Remove the "../../" prefix in "../../cciss/c0d0"
    first_internal_disk_name=\$(echo \$device_symlink | awk -F'/' '{print
\$(NF-1)"/"\$NF}')
 fi

  ks_partition_cmd="ignoredisk --only-use=\$first_internal_disk_name"

fi



# Allow anaconda to partition the system as needed
# using just the first disk

cat <<PART_EOF > /tmp/partition_info

autopart
$ks_partition_cmd

PART_EOF
======== END SNIPPET ============


Thanks
Balaji

[Mann, Owen]

That's a good one. I don't know of anything in the SCSI standard that might say
whether a disk is internal or not. My only thought is use controller or enclosure-specific
commands to determine if the port or backplane the disk is connected to is an external
type. The caveats are that you need hardware-specific knowledge of what you might expect
to find, and the utilities for that (e.g. hpacucli/megacli and sg_safte).

Owen Mann, Interactive Data Real Time Services
60 Codman Hill Rd, Boxborough, MA 01719
978-795-3758 [e-mail]<mailto:[e-mail]>

From: cobbler-bounces(a)lists.fedorahosted.org
[mailto:[e-mail]] On Behalf Of Parthasarathy, Balaji (BCS,
Cupertino, USA)
Sent: Wednesday, June 20, 2012 8:03 PM
To: cobbler(a)lists.fedorahosted.org
Subject: [cobbler] How to determine "internal" disk in a Cobbler
snippet/kickstart

Hi,
When I install a system using Cobbler using kickstart/snippet, I want to only do the
partitioning of

1.       Internal only disk

2.       Only one disk, if multiple exist

3.       Handle RAID/non-RAID scenarios

Is there a good/reliable way in Linux (RHEL and Fedora specifically) to determine #1?
Since we are in the installation environment, some commands (like lsscsi) aren’t
available. Here’s what I’m using in my snippet currently.

======== BEGIN SNIPPET ============
# Look for any 'scsi' or 'cciss' device; weed out output with partitions
of those
# devices (part) and cd/dvd devices (sr); grab the first line of the remaining output.
# Assumption is first scsi device is "internal" disk. We want to partition only
# the first internal disk.
ls_output=\$(ls -l /dev/disk/by-path/pci* | grep -i -e scsi -e cciss | grep -v -i -e part
-e sr | head -n 1)

# If we did not get any proper data for disk devices, just let anaconda do auto
partitioning
# and use all/whatever disks anaconda finds, rather than throw an error.
if [[ -z "$ls_output" ]]
then
  ks_partition_cmd=""
else
  # NOTE: we are parsing a output that looks like this:
  #     lrwxrwxrwx. 1 root root 9 Jun 18 13:01
/dev/disk/by-path/pci-0000:0c:00.0-scsi-0:0:0:1 -> ../../sda
  device_symlink=\$(echo \$ls_output | awk '{print \$11}')

  if [[ ! -z \$(echo \$device_symlink | grep -i sd) ]]
  then
    # The first internal disk is a non-RAID disk.
    # Remove the "../../" prefix in "../../sda"
    first_internal_disk_name=\${device_symlink\#\#*/}
  else
    # The first internal disk is a RAID disk.
    # Remove the "../../" prefix in "../../cciss/c0d0"
    first_internal_disk_name=\$(echo \$device_symlink | awk -F'/' '{print
\$(NF-1)"/"\$NF}')
 fi

  ks_partition_cmd="ignoredisk --only-use=\$first_internal_disk_name"

fi



# Allow anaconda to partition the system as needed
# using just the first disk

cat <<PART_EOF > /tmp/partition_info

autopart
$ks_partition_cmd

PART_EOF
======== END SNIPPET ============


Thanks
Balaji


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