CentOS7 - oVirt - iSCSI

Here is the process I followed POST oVirt Hosted Engine 7.2.1 RC4 install.

Make sure all of your iSCSI targets have the correct security on your SAN devices.
If you are using Jumbo Frames (MTU 9000), make sure you can ping your targets with large packets
```
ping -M do -s 8972 10.10.9.10
ping -M do -s 8972 10.10.10.10
```
Restart CentOS-oVirt host and then:
1. check what paths are connected
```
iscsiadm --m session --op show
```
  should output something like
```
tcp: [1] 10.10.10.10:3260,1 iqn.2000-01.com.synology:DATACluster.Target-OVENGINE.223b368d55 (non-flash)
tcp: [2] 10.10.9.10:3260,1 iqn.2000-01.com.synology:DATACluster.Target-OVENGINE.223b368d55 (non-flash)
```
2. If you want to add *all* available targets to the host *BE CAREFUL* as if you dont want to add all – skip to step 3
```
iscsiadm -m discovery -t st -p 10.10.10.10 -o new
```
  now if you reboot – all of the targets should show when you run
```
iscsiadm --m session --op show
```
3. If you want to add your targets one-by-one (Make sure you only add each target once and MPIO will find the additional paths)
```
iscsiadm -m node -T iqn.2000-01.com.synology:DATACluster.Target-OVIRT.223b368d55 -l -p 10.10.10.10:3260  -o new
```
  make sure to change iqn, ip, port to match your environment. You’ll want to run the above command for each target/path and then you can use
```
iscsiadm -m session
```
  to view your progress.
4. Check your multipath settings too by using
```
multipath -ll
```
  You can edit /etc/multipath.conf to suit your needs and then
```
service multipathd reload
multipath -ll
```
5. If you need to remove a iSCSI target path you can
```
iscsiadm -m node -u -T iqn.2000-01.com.synology:DATACluster.Target-1.223b368d55 -p 10.10.10.10:3260 
iscsiadm -m node -o delete -T iqn.2000-01.com.synology:DATACluster.Target-1.223b368d55 -p 10.10.10.10:3260
```
  which will logout of the target and then the second line will remove it from your host
6. Now using the oVirt Gui – this is for 2 paths. If you require more, create iSCSI03,04,05…
  1. Network – Networks
    1. New
      1. Name: iSCSI01
      2. Label: iSCSI01
      3. VLAN: 2 (If required)
      4. un-check VM network
      5. MTU: 9000 (If required)
      6. Cluster – Remove check mark from Required
    2. New
      1. same as above but iSCSI02
  2. Compute – Data Centers
    1. Click on the Default
    2. iSCSI Multipathing (tab)
      1. add
        
        Name: iscsimpio
        
        Check off iSCSI01, iSCSI02 under logical networks
        
        Check off all of your required targets
  3. Compute – Hosts
    1. – Click the host
    2. Network Interfaces (tab)
    3. Setup Host Networks (button)
      1. drag iSCSI01 from the right to the NIC on the left that is one of your iSCSI NICS.
      2. click the pencil beside iSCSI01 and config the IP address, mask, and MTU
      3. drag iSCSI02 from the right to the NIC on the left that is one of your iSCSI NICS.
      4. click the pencil beside iSCSI02 and config the IP address, mask, and MTU

Some additional iSCSI commands:

#check MPIO
multipath -ll

#iSCSI show connections
iscsiadm --m session --op show

#iSCSI Logout All
iscsiadm --mode node --logoutall=all 

#iSCSI Login All
iscsiadm -m node -l

#iSCSI OFF
service iscsi stop
chkconfig iscsi off

#iSCSI ON
chkconfig iscsi on
service iscsi start

CentOS7 – oVirt – iSCSI

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