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This post demonstrates how to enable two-way or mutual CHAP on iSCSI luns between Ubuntu Server 14.10 and NetApp storage. The aggregate, lun and disk sizes are small in this HOWTO to keep it simple. Note that Ubuntu follows the no root model so you must use sudo on privileged command. I will not show every “enter password” prompt in the doc. When you see it, just enter your password.

1) Install open-iscsi on your server.
> sudo apt-get install open-iscsi
> sudo reboot (don’t argue with me, just do it!)

2) Display your server’s new iscsi initiator or iqn nodename.
> sudo cat /etc/iscsi/initiatorname.iscsi

3) On the NetApp filer, create the volume that will hold the iscsi luns. This command assumes you have aggregrate aggr1 already created. If not use an aggregate that has enough room for your volume.
netapp> vol create MCHAPVOL aggr1 10g

4) On the NetApp filer, create the lun in the volume.
netapp> lun create -s 5g -t linux /vol/MCHAPVOL/UB1410_iSCSI_MCHAP_01

5) On the NetApp filer, create an igroup and add the Linux iscsi nodename or iqn from step 2 above to it.
netapp> igroup create -i -t linux ISCSI_MCHAP_UB1410
netapp> igroup add ISCSI_MCHAP_UB1410 iqn.1993-08.org.debian:01:ce45f9ecc9b
netapp> igroup show

ISCSI_MCHAP_UB1410 (iSCSI) (ostype: linux):
iqn.1993-08.org.debian:01:ce45f9ecc9b (not logged in)

6) Map the lun to the iscsi-group and give it lun ID 01.
netapp> lun map /vol/MCHAPVOL/UB1410_iSCSI_MCHAP_01 ISCSI_MCHAP_UB1410 01

7) Obtain the NetApp target nodename.
netapp> iscsi nodename
iSCSI target nodename: iqn.1992-08.com.netapp:sn.4055372815

8) Set the CHAP secret on the NetApp controller.
netapp> iscsi security add -i iqn.1993-08.org.debian:01:ce45f9ecc9b -s chap -p MCHAPUB1410 -n iqn.1993-08.org.debian:01:ce45f9ecc9b -o NETAPPMCHAP -m iqn.1992-08.com.netapp:sn.4055372815

netapp> iscsi security show
init: iqn.1993-08.org.debian:01:ce45f9ecc9b auth: CHAP Local Inbound password: **** Inbound username: iqn.1993-08.org.debian:01:ce45f9ecc9b Outbound
password: **** Outbound username: iqn.1992-08.com.netapp:sn.4055372815

9) On the server, edit your /etc/iscsi/iscsi.conf file and set the parameters below. You can just copy this into the file under iscsid.startup = /usr/sbin/iscsid but make sure you comment out node.startup = manual just below it. Since you want it to start automatically comment out node.leading_login = No.

> sudo vi /etc/iscsi/iscsid.conf:
node.startup = automatic
node.session.auth.authmethod = CHAP
node.session.auth.username = iqn.1993-08.org.debian:01:ce45f9ecc9b
node.session.auth.password = MCHAPUB1410
node.session.auth.username_in = iqn.1992-08.com.netapp:sn.4055372815
node.session.auth.password_in = NETAPPMCHAP
discovery.sendtargets.auth.authmethod = CHAP
discovery.sendtargets.auth.username = iqn.1993-08.org.debian:01:ce45f9ecc9b
discovery.sendtargets.auth.password = MCHAPUB1410
discovery.sendtargets.auth.username_in = iqn.1992-08.com.netapp:sn.4055372815
discovery.sendtargets.auth.password_in = NETAPPMCHAP
> wq!

10) On the server, discover your iSCSI target (your NetApp storage system).
> sudo iscsiadm -m discovery -t st -p,1000 iqn.1992-08.com.netapp:sn.4055372815

> sudo iscsiadm -m node  (this should display the same as above),1000 iqn.1992-08.com.netapp:sn.4055372815

11) On the server, manually login to the iSCSI target (your storage array). Note there are two “- -” dashed in front of targetname and login.
> sudo iscsiadm -m node –-targetname “iqn.1992-08.com.netapp:sn.4055372815” -–login

Logging in to [iface: default, target: iqn.1992-08.com.netapp:sn.4055372815, portal:,3260] (multiple)
Login to [iface: default, target: iqn.1992-08.com.netapp:sn.4055372815, portal:,3260] successful.

On the NetApp storage console you should see the iSCSI sessions:
[iscsi.notice:notice]: ISCSI:
New session from initiator iqn.1993-08.org.debian:01:ce45f9ecc9b at IP addr

Verify the iSCSI session on the filer:
netapp> iscsi session show
Session 1
Initiator Information
Initiator Name: iqn.1993-08.org.debian:01:ce45f9ecc9b
ISID: 00:02:3d:01:00:00
Initiator Alias: ub1410

12) Stop and start the iscsi service on the server.
> sudo service open-iscsi stop
Pause for 10 seconds and then run the next command.
> sudo service open-iscsi start

13) From the server, check your session.
> sudo iscsiadm -m session -P 1

14) From the server, check the NetApp iSCSI details. Note that mode, targetname and portal have two “- -” dashes in front of them.
> sudo iscsiadm –mode node –targetname “iqn.1992-08.com.netapp:sn.4055372815” –portal

15) From the server, find and format the new lun (new disk). The command below will find the device. In this case its sdb.
> dmesg | grep “unknown partition table”
[ 1930.949065]  sdb: unknown partition table
[ 2167.186068]  sdb: unknown partition table

> sudo fdisk /dev/sdb  (note: commands are in bold red below)

Welcome to fdisk (util-linux 2.25.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0xe4775fd7.

Command (m for help): w

The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.

> sudo fdisk /dev/sdb

Command (m for help): n
Partition type
p   primary (0 primary, 0 extended, 4 free)
e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-10485759, default 2048): press enter
Last sector, +sectors or +size{K,M,G,T,P} (2048-10485759, default 10485759): press enter

Created a new partition 1 of type ‘Linux’ and of size 5 GiB.

Command (m for help): p
Disk /dev/sdb: 5 GiB, 5368709120 bytes, 10485760 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 65536 bytes
Disklabel type: dos
Disk identifier: 0xc68508a4

Device     Boot Start      End  Sectors Size Id Type
/dev/sdb1        2048 10485759 10483712   5G 83 Linux

Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.

16) On the server, create the Linux file system on the new partition.
> sudo mkfs -t ext4 /dev/sdb1
mke2fs 1.42.10 (18-May-2014)
Discarding device blocks: done
Creating filesystem with 1310464 4k blocks and 327680 inodes
Filesystem UUID: d125b8ff-a690-4cbb-925d-645764d41172
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

17) Verify the partition.
> sudo blkid /dev/sdb1
/dev/sdb1: UUID=”d125b8ff-a690-4cbb-925d-645764d41172″ TYPE=”ext4″ PARTUUID=”c68508a4-01″

18) Create the mount point and manually mount the directory.
> sudo mkdir /newiscsilun
> sudo mount /dev/sdb1 /newiscsilun
> df -h | grep newiscsilun
/dev/sdb1  4.8G   10M  4.6G   1% /newiscsilun

19) Add the new mount point to /etc/fstab.
> sudo vi /etc/fstab
/dev/sdb1 /newiscsilun ext4 _netdev 0 0
> wq!

Note: the _netdev option is important so that it doesn’t try mounting the target before the network is available.

20) Test that it survives a reboot by rebooting the server now. With the _netdev set, iscsi starts and your CHAP logins should take place before it attempts to mount. After the reboot, login and verify that it is mounted.

> df -h | grep newiscsilun
/dev/sdb1  4.8G   10M  4.6G   1% /newiscsilun

21) On the server you can check session stats.
> sudo iscsiadm -m session -s

22) As root, change permissions on /etc/iscsi/iscsid.conf. I’m not sure why they haven’t fixed this clear text CHAP password in a file issue so just make sure only root can read/write the file.
> sudo chmod 600 /etc/iscsi/iscsid.conf

23) On the NetApp storage you can verify the lun and the server’s session.
netapp> lun show -v /vol/MCHAPVOL/UB1410_iSCSI_MCHAP_01
/vol/MCHAPVOL/UB1410_iSCSI_MCHAP_01      5g (5368709120)    (r/w, online, mapped)
Serial#: BQVJ3]DxwBcB
Share: none
Space Reservation: enabled
Multiprotocol Type: linux
Maps: ISCSI_MCHAP_UB1410=1
Occupied Size:  132.8m (139202560)
Creation Time: Mon Dec 29 13:33:18 EST 2014
Cluster Shared Volume Information: 0x0

You can also get stats with the command below.
netapp>  iscsi session show -v