CloudByte Storage and OpenStack LVM Driver

[ OPENSTACK SETUP ]
May 12th, 2016

OpenStack LVM using CloudByte’s iSCSI Volume

To use CloudByte’s iSCSI volume as the underlying source for lvm we need to follow some guidelines:

Following steps were done on

  • Ubuntu 14.04 that hosted the OpenStack Liberty
  • ElastiCenter 1.3.0.824

Using ElastiCenter UI

  • Create an iSCSI volume in CloudByte ElastiCenter.
  • Set the initiator group to ‘ALL’ for this new volume.

On Ubuntu box

Install iSCSI Initiator

  • Configure Ubuntu Server as an iSCSI initiator install the open-iscsi package.

    sudo apt install open-iscsi

iSCSI Initiator Configuration

  • Edit /etc/iscsi/iscsid.conf

    node.startup = automatic

  • Check the available targets

    sudo iscsiadm -m discovery -t st -p 192.168.0.10

options
-m: determines the mode that iscsiadm executes in.
-t: specifies the type of discovery.
-p: option indicates the target IP address.

NOTE : Change example 192.168.0.10 to the target IP address on your network.

  • If the target is available you should see output similar to the following:

    192.168.0.10:3260,1 iqn.1992-05.com.emc:sl7b92030000520000-2

NOTE : The iqn number and IP address above will vary depending on your hardware.

  • Connect to the iSCSI target

    sudo iscsiadm -m node --login

  • Check to make sure that the new disk has been detected using dmesg:

    dmesg | grep sd

[    4.322384] sd 2:0:0:0: Attached scsi generic sg1 type 0
[    4.322797] sd 2:0:0:0: [sda] 41943040 512-byte logical blocks: (21.4 GB/20.0 GiB)
[    4.322843] sd 2:0:0:0: [sda] Write Protect is off
[    4.322846] sd 2:0:0:0: [sda] Mode Sense: 03 00 00 00
[    4.322896] sd 2:0:0:0: [sda] Cache data unavailable
[    4.322899] sd 2:0:0:0: [sda] Assuming drive cache: write through
[    4.323230] sd 2:0:0:0: [sda] Cache data unavailable
[    4.323233] sd 2:0:0:0: [sda] Assuming drive cache: write through
[    4.325312]  sda: sda1 sda2 < sda5 >
[    4.325729] sd 2:0:0:0: [sda] Cache data unavailable
[    4.325732] sd 2:0:0:0: [sda] Assuming drive cache: write through
[    4.325735] sd 2:0:0:0: [sda] Attached SCSI disk
[ 2486.941805] sd 4:0:0:3: Attached scsi generic sg3 type 0
[ 2486.952093] sd 4:0:0:3: [sdb] 1126400000 512-byte logical blocks: (576 GB/537 GiB)
[ 2486.954195] sd 4:0:0:3: [sdb] Write Protect is off
[ 2486.954200] sd 4:0:0:3: [sdb] Mode Sense: 8f 00 00 08
[ 2486.954692] sd 4:0:0:3: [sdb] Write cache: disabled, read cache: enabled, doesn't
support DPO or FUA
[ 2486.960577]  sdb: sdb1
[ 2486.964862] sd 4:0:0:3: [sdb] Attached SCSI disk
  • In the output above sdb is the new iSCSI disk.
    • this is just an example; the output you see on your screen will vary.
  • Next Steps:
    • create a partition,
    • format the file system, and
    • login to the new iSCSI disk.
    sudo fdisk /dev/sdb
n
p
enter
enter
w

NOTE : The above commands are from inside the fdisk utility; see man fdisk
       for more detailed instructions.
NOTE : cfdisk utility is sometimes more user friendly.

  • Format the file system

    sudo mkfs.ext4 /dev/sdb1

Configuring CloudByte’s iSCSI volume as LVM volume group

  • Verify existence of lvm volume groups

    sudo vgs

You may get the following output:
VG                        #PV #LV #SN Attr   VSize  VFree
stack-volumes-default       1   0   0 wz--n- 10.01g 10.01g
stack-volumes-lvmdriver-1   1   1   0 wz--n- 10.01g  9.01g

  • Create a new lvm volume group on above created partition

    sudo pvcreate /dev/sdb1
sudo vgcreate cinder-cb-volumes /dev/sdb1

NOTE : Assuming /dev/sdb is the partition you want to use
NOTE : here /dev/sdb1 is a valid unused device

NOTE : If executing 'pvcreate' results into below error
       Device /dev/sdb1 not found (or ignored by filtering).
Try below :
      sudo vi /etc/lvm/lvm.conf
      Comment the following line
      global_filter = [ "a|loop0|", "a|loop1|", "r|.*|" ]  # from devstack

  • Verify existence of new lvm volume group that was just added.

    sudo vgs

VG                        #PV #LV #SN Attr   VSize  VFree
cinder-cb-volumes           1   1   0 wz--n- 10.00g  9.00g
stack-volumes-default       1   0   0 wz--n- 10.01g 10.01g
stack-volumes-lvmdriver-1   1   1   0 wz--n- 10.01g  9.01g
  • Register a new LVM backend in cinder.conf and
  • Add the newly created volume-group to this new LVM backend
    • e.g. below edit
      • registers a new backend called ‘cloudbyte-lvm’
      • adds ‘cinder-cb-volumes’ as the volume group
    sudo vi /etc/cinder/cinder.conf

[DEFAULT]
default_volume_type = lvmdriver-1,cb-lvm
enabled_backends = lvmdriver-1, cloudbyte-lvm

[cloudbyte-lvm]
lvm_type = default
iscsi_helper = tgtadm
volume_group = cinder-cb-volumes
volume_driver = cinder.volume.drivers.lvm.LVMVolumeDriver
volume_backend_name = cloudbyte-lvm

  • Create a new volume type for the backend that was newly created

    cinder type-create cb-lvm
cinder type-key cb-lvm set volume_backend_name cloudbyte-lvm

  • Restart the cinder-services

    service cinder-api restart
service cinder-scheduler restart
service cinder-volume restart

service cinder-api status
service cinder-scheduler status
service cinder-volume status

  • Verify the volume types & specs associated with them

    cinder extra-specs-list
+------------------------------------+------+------------------------------------------+
|                 ID                 | Name |            extra_specs                   |
+------------------------------------+------+------------------------------------------+
|b19f5d36-032c-4e77-a498-875cebfa325a|cb-lvm|{u'volume_backend_name':u'cloudbyte-lvm'} |
+------------------------------------+------+------------------------------------------+

Abhishek Shrivastava