# Connect iSCSI LUNs to RHEL/CENTOS
## Description: ------- This article will walk through attaching an iSCSI LUN to RHEL/CentOS 7.
#### COMPATABILITY NOTICE:
These instructions are only compatible with CentOS 7

and RHEL 7

## Pre-Requisites: ------- Install the iSCSI libraries on the server: ```bash yum -y install iscsi-initiator-utils device-mapper-multipath lldpad ```
## Start iSCSI Services: ------- Once all of the pre-requisite packages have been installed, all of the iscsi services need to be started and configured to start on boot. ```bash systemctl start iscsi; systemctl start iscsid ; systemctl start multipathd ; systemctl enable iscsi ; systemctl enable iscsid ; systemctl enable multipathd ; ```
## Configure Interface: ------- #### iSCSI VLAN:
Ensure that either the chassis or switch port that the server is connected to is set to the proper iSCSI VLAN or the interface will not be able to communicate with the iSCSI Target. ```bash vim /etc/sysconfig/network-scipts/ifcfg-enoxxxx ```
```bash Adapter TYPE=Ethernet BOOTPROTO=none DEFROUTE=no IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_AUTOCONF=no IPV6_DEFROUTE=no IPV6_FAILURE_FATAL=no NAME=enp8s0 UUID=5e72182e-82ca-4072-a376-1645852871b4 DEVICE=enp8s0 ONBOOT=yes MTU=9000 DCB=on DCB_APP_FCOE=no DCB_APP_FCOE_ENABLE=no DCB_APP_ISCSI=yes DCB_APP_ISCSI_CFG=40 DCB_APP_ISCSI_ENABLE=yes DCB_APP_ISCSI_ADVERTISE=yes DCB_APP_ISCSI_WILLING=yes PEERDNS=yes PEERROUTES=yes IPV6_PEERDNS=no IPV6_PEERROUTES=no IPV6_PRIVACY=no IPADDR=172.1.2.3 NETMASK=255.255.0.0 ```
## Get Initiator Name: ------- Once the interfaces have been configured, we need the initiator name, which will be used on the iSCSI target, to allow access to the iSCSI resource. ```bash cat /etc/iscsi/initiatorname.iscsi ```
```bash InitiatorName=iqn.1994-05.com.redhat:ab92cf327a ```
## Perform Discovery: ------- Assuming that the server initiator has been granted access to the LUN on the target, performing a discovery should show the LUNs that have been assigned to the initiator. ```bash iscsiadm -m discovery -t sendtargets -p 172.2.3.254 ```
## Verify discovery: ------- Use the commands below to show information about the LUNs that have been assigned to the initiator. ```bash iscsiadm -m session -o show iscsiadm -m node -o show ```
## Login to the Target: ------- Logging onto the target should map the LUNs to the server. Once logged in, the LUNs should be visable on the server. ```bash iscsiadm -m node --login ```
## Verify Connectivity: ------- ```bash cat /proc/partitions ```
## Prepare the LUNs ------- Fdisk the LUNs as you would a standard disk
## Mount the LUNs ------- Edit the __/etc/fstab__ file and add an entry similar to the following: * In this example the LUN is being mounted to /var/lib/docker, before mounting ensure that the mount target directory exists. ```bash /dev/sdb1 /var/lib/docker/ ext4 defaults,_netdev 0 0 ```
## Post Requisites: -------
## References: ------- [clusterfrak.com](http://clusterfrak.com/sysops/linux/linux_iscsi/)