Procedure 16.1. Creating a DLM Resource¶

	DLM Resource for Both cLVM and OCFS2
Both cLVM and OCFS2 need a DLM resource that runs on all nodes in the cluster and therefore is usually configured as a clone. If you have a setup that includes both OCFS2 and cLVM, configuring one DLM resource for both OCFS2 and cLVM is enough.

1. Start a shell and log in as root.

2. Run crm configure.

3. Check the current configuration of the cluster resources with show.

4. If you have already configured a DLM resource (and a corresponding base group and base clone), continue with Procedure 16.2, “Creating LVM and cLVM Resources”.

   Otherwise, configure a DLM resource and a corresponding base group and base clone as described in Procedure 14.1, “Configuring DLM and O2CB Resources”.

5. Leave the crm live configuration with exit.

Procedure 16.2. Creating LVM and cLVM Resources¶

1. Start a shell and log in as root.

2. Run crm configure.

3. Configure a cLVM resource as follows:

   primitive clvm ocf:lvm2:clvmd \
         params daemon_timeout="30"

4. Configure an LVM resource for the volume group as follows:

   primitive vg1 ocf:heartbeat:LVM \
         params volgrpname="cluster-vg" \
         op monitor interval="60" timeout="60"

5. If you want the volume group to be activated exclusively on one node, configure the LVM resource as described below and omit Step 6:

   primitive vg1 ocf:heartbeat:LVM \
         params volgrpname="cluster-vg" exclusive="yes" \
         op monitor interval="60" timeout="60"

   In this case, cLVM will protect all logical volumes within the VG from being activated on multiple nodes, as an additional measure of protection for non-clustered applications.

6. To ensure that the cLVM and LVM resources are activated cluster-wide, add both primitives to the base group you have created in Procedure 14.1, “Configuring DLM and O2CB Resources”:

   1. Enter

      edit base-group

   2. In the vi editor that opens, modify the group as follows and save your changes:

      group base-group dlm o2cb clvm vg1 ocfs2-1

      	Setup Without OCFS2
      If your setup does not include OCFS2, omit the ocfs2-1 primitive from the base group. The oc2cb primitive can be configured and included in the group anyway, regardless of whether you use OCFS2 or not.

7. Review your changes with show. To check if you have configured all needed resources, also refer to Appendix B, Example Configuration for OCFS2 and cLVM.

8. If everything is correct, submit your changes with commit and leave the crm live configuration with exit.

Procedure 16.3. Configuring iSCSI Targets (SAN)¶

1. Run YaST and click Network Services+iSCSI Target to start the iSCSI Server module.

2. If you want to start the iSCSI target whenever your computer is booted, choose When Booting, otherwise choose Manually.

3. If you have a firewall running, enable Open Port in Firewall.

4. Switch to the Global tab. If you need authentication enable incoming or outgoing authentication or both. In this example, we select No Authentication.

5. Add a new iSCSI target:

   1. Switch to the Targets tab.

   2. Click Add.

   3. Enter a target name. The name has to be formatted like this:

      iqn.DATE.DOMAIN

      For more information about the format, refer to , Section 3.2.6.3.1. Type "iqn." (iSCSI Qualified Name) .

   4. If you want a more descriptive name, you can change it as long as your identifier is unique for your different targets.

   5. Click Add.

   6. Enter the device name in Path and use a Scsiid.

   7. Click Next twice.

6. Confirm the warning box with Yes.

7. Open the configuration file /etc/iscsi/iscsi.conf and change the parameter node.startup to automatic.

Procedure 16.4. Configuring iSCSI Initiators¶

1. Run YaST and click Network Services+iSCSI Initiator.

2. If you want to start the iSCSI initiator whenever your computer is booted, choose When Booting, otherwise set Manually.

3. Change to the Discovery tab and click the Discovery button.

4. Add your IP address and your port of your iSCSI target (see Procedure 16.3, “Configuring iSCSI Targets (SAN)”). Normally, you can leave the port as it is and use the default value.

5. If you use authentication, insert the incoming and outgoing username and password, otherwise activate No Authentication.

6. Select Next. The found connections are displayed in the list.

7. Proceed with Finish.

8. Open a shell, log in as root.

9. Test if the iSCSI initiator has been started successfully:

   iscsiadm -m discovery -t st -p 192.168.3.100
   192.168.3.100:3260,1 iqn.2010-03.de.jupiter:san1

10. Establish a session:

    iscsiadm -m node -l
    Logging in to [iface: default, target: iqn.2010-03.de.jupiter:san2, portal: 192.168.3.100,3260]
    Logging in to [iface: default, target: iqn.2010-03.de.venus:san1, portal: 192.168.3.101,3260]
    Login to [iface: default, target: iqn.2010-03.de.jupiter:san2, portal: 192.168.3.100,3260]: successful
    Login to [iface: default, target: iqn.2010-03.de.venus:san1, portal: 192.168.3.101,3260]: successful

    See the device names with lsscsi:

    ...
    [4:0:0:2]    disk    IET      ...     0     /dev/sdd
    [5:0:0:1]    disk    IET      ...     0     /dev/sde

    Look for entries with IET in their third column. In this case, the devices are /dev/sdd and /dev/sde.

Procedure 16.5. Creating the LVM Volume Groups¶

1. Open a root shell on one of the nodes you have run the iSCSI initiator from Procedure 16.4, “Configuring iSCSI Initiators”.

2. Prepare the physical volume for LVM with the command pvcreate on the disks /dev/sdd and /dev/sde:

   pvcreate /dev/sdd
   pvcreate /dev/sde

3. Create the cluster-aware volume group on both disks:

   vgcreate --clustered y clustervg /dev/sdd /dev/sde

4. Create logical volumes as needed:

   lvcreate --name clusterlv --size 500M clustervg

5. Check the physical volume with pvdisplay:

     --- Physical volume ---
         PV Name               /dev/sdd
         VG Name               clustervg
         PV Size               509,88 MB / not usable 1,88 MB
         Allocatable           yes
         PE Size (KByte)       4096
         Total PE              127
         Free PE               127
         Allocated PE          0
         PV UUID               52okH4-nv3z-2AUL-GhAN-8DAZ-GMtU-Xrn9Kh
         
         --- Physical volume ---
         PV Name               /dev/sde
         VG Name               clustervg
         PV Size               509,84 MB / not usable 1,84 MB
         Allocatable           yes
         PE Size (KByte)       4096
         Total PE              127
         Free PE               127
         Allocated PE          0
         PV UUID               Ouj3Xm-AI58-lxB1-mWm2-xn51-agM2-0UuHFC

6. Check the volume group with vgdisplay:

     --- Volume group ---
         VG Name               clustervg
         System ID
         Format                lvm2
         Metadata Areas        2
         Metadata Sequence No  1
         VG Access             read/write
         VG Status             resizable
         Clustered             yes
         Shared                no
         MAX LV                0
         Cur LV                0
         Open LV               0
         Max PV                0
         Cur PV                2
         Act PV                2
         VG Size               1016,00 MB
         PE Size               4,00 MB
         Total PE              254
         Alloc PE / Size       0 / 0
         Free  PE / Size       254 / 1016,00 MB
         VG UUID               UCyWw8-2jqV-enuT-KH4d-NXQI-JhH3-J24anD

Procedure 16.6. Creating a Cluster-Aware Volume Group With DRBD¶

1. Create a primary/primary DRBD resource:

   1. First, set up a DRBD device as primary/secondary as described in Procedure 15.1, “Manually Configuring DRBD”. Make sure the disk state is up-to-date on both nodes. Check this with cat /proc/drbd or with rcdrbd status.

   2. Add the following options to your configuration file (usually something like /etc/drbd.d/r0.res):

      resource r0 {
        startup {
          become-primary-on both;
        }
      
        net {
           allow-two-primaries;
        }
        ...
      }

   3. Copy the changed configuration file to the other node, for example:

      scp /etc/drbd.d/r0.res venus:/etc/drbd.d/

   4. Run the following commands on both nodes:

      drbdadm disconnect r0
      drbdadm connect r0
      drbdadm primary r0

   5. Check the status of your nodes:

      cat /proc/drbd
      ...
       0: cs:Connected ro:Primary/Primary ds:UpToDate/UpToDate C r----

2. Include the clvmd resource as a clone in the pacemaker configuration, and make it depend on the DLM clone resource. See Procedure 16.1, “Creating a DLM Resource” for detailed instructions. Before proceeding, confirm that these resources have started successfully on your cluster. You may use crm_mon or the GUI to check the running services.

3. Prepare the physical volume for LVM with the command pvcreate. For example, on the device /dev/drbd_r0 the command would look like this:

   pvcreate /dev/drbd_r0

4. Create a cluster-aware volume group:

   vgcreate --clustered y myclusterfs /dev/drbd_r0

5. Create logical volumes as needed. You may probably want to change the size of the logical volume. For example, create a 4 GB logical volume with the following command:

   lvcreate --name testlv -L 4G myclusterfs

6. The logical volumes within the VG are now available as file system mounts or raw usage. Ensure that services using them have proper dependencies to collocate them with and order them after the VG has been activated.