iSCSI and MPIO on Azure VMs

1Network and two VMs

Create a VNet, a target VM with a 4 GiB data disk, and an initiator VM. Public IPs are only for apt; no inbound port is opened:

az group create --name rg-saat-l57 --location centralindia --tags course=saatvedha-azure lesson=57 -o none
az network vnet create --resource-group rg-saat-l57 --name vnet-l57 --address-prefixes 10.57.0.0/16 --subnet-name snet-san --subnet-prefixes 10.57.1.0/24 -o none
az vm create --resource-group rg-saat-l57 --name vm-target --image Canonical:ubuntu-24_04-lts:server:latest --size Standard_B1s --vnet-name vnet-l57 --subnet snet-san --private-ip-address 10.57.1.4 --public-ip-sku Standard --nsg-rule NONE --admin-username azureuser --generate-ssh-keys --tags course=saatvedha-azure lesson=57 -o none --data-disk-sizes-gb 4
az vm create --resource-group rg-saat-l57 --name vm-init --image Canonical:ubuntu-24_04-lts:server:latest --size Standard_B1s --vnet-name vnet-l57 --subnet snet-san --private-ip-address 10.57.1.10 --public-ip-sku Standard --nsg-rule NONE --admin-username azureuser --generate-ssh-keys --tags course=saatvedha-azure lesson=57 -o none
az network nic ip-config create --resource-group rg-saat-l57 --nic-name vm-targetVMNic --name ipconfig2 --private-ip-address 10.57.1.5 -o none

The second IP config gives the target a second portal address. Azure only delivers traffic to an IP that’s on the NIC, and the OS must also have it, which the target script adds.

2Build the iSCSI target

Save this as C:\azure-lab\iscsi\target.sh:

#!/bin/bash
# iSCSI target on vm-target: one LUN, two portals, one allowed initiator
set -e
apt-get update -qq > /dev/null
DEBIAN_FRONTEND=noninteractive apt-get install -y -qq targetcli-fb > /dev/null
ip addr add 10.57.1.5/24 dev eth0 || true
T=iqn.2026-10.com.saatvedha:target1
targetcli /backstores/block create name=disk1 dev=/dev/disk/azure/scsi1/lun0
targetcli /iscsi create $T
targetcli /iscsi/$T/tpg1/luns create /backstores/block/disk1
targetcli /iscsi/$T/tpg1/portals delete 0.0.0.0 3260
targetcli /iscsi/$T/tpg1/portals create 10.57.1.4 3260
targetcli /iscsi/$T/tpg1/portals create 10.57.1.5 3260
targetcli /iscsi/$T/tpg1/acls create iqn.2026-10.com.saatvedha:vm-init
targetcli saveconfig > /dev/null
targetcli ls /iscsi

Run it on vm-target:

az vm run-command invoke --resource-group rg-saat-l57 --name vm-target --command-id RunShellScript --scripts '@C:\azure-lab\iscsi\target.sh' --query "value[0].message" -o tsv

The end of the output should look something like this:

o- iscsi ............................................ [Targets: 1]
  o- iqn.2026-10.com.saatvedha:target1 ............... [TPGs: 1]
    o- tpg1 .............................. [no-gen-acls, no-auth]
      o- acls .......................................... [ACLs: 1]
      | o- iqn.2026-10.com.saatvedha:vm-init .... [Mapped LUNs: 1]
      o- luns .......................................... [LUNs: 1]
      | o- lun0 ............. [block/disk1 (/dev/disk/azure/scsi1/lun0)]
      o- portals .................................... [Portals: 2]
        o- 10.57.1.4:3260 ................................... [OK]
        o- 10.57.1.5:3260 ................................... [OK]

3Connect the initiator over two paths

Save this as C:\azure-lab\iscsi\initiator.sh:

#!/bin/bash
# iSCSI initiator with multipath on vm-init
apt-get update -qq > /dev/null
DEBIAN_FRONTEND=noninteractive apt-get install -y -qq open-iscsi multipath-tools > /dev/null
echo InitiatorName=iqn.2026-10.com.saatvedha:vm-init > /etc/iscsi/initiatorname.iscsi
sed -i 's/^node.session.timeo.replacement_timeout = .*/node.session.timeo.replacement_timeout = 5/' /etc/iscsi/iscsid.conf
cat > /etc/multipath.conf <<'EOF'
defaults {
    user_friendly_names yes
    find_multipaths yes
}
blacklist {
    device {
        vendor "Msft"
        product "Virtual Disk"
    }
}
EOF
systemctl restart iscsid multipathd
iscsiadm -m discovery -t sendtargets -p 10.57.1.4
iscsiadm -m node --login > /dev/null
sleep 5
iscsiadm -m session
multipath -ll

Run it on vm-init:

az vm run-command invoke --resource-group rg-saat-l57 --name vm-init --command-id RunShellScript --scripts '@C:\azure-lab\iscsi\initiator.sh' --query "value[0].message" -o tsv

You should see something like this:

10.57.1.4:3260,1 iqn.2026-10.com.saatvedha:target1
10.57.1.5:3260,1 iqn.2026-10.com.saatvedha:target1
tcp: [1] 10.57.1.4:3260,1 iqn.2026-10.com.saatvedha:target1 (non-flash)
tcp: [2] 10.57.1.5:3260,1 iqn.2026-10.com.saatvedha:target1 (non-flash)
mpatha (36001405d2f6e1a0c9b14b5f9a1c3e7d2) dm-0 LIO-ORG,disk1
size=4.0G features='0' hwhandler='1 alua' wp=rw
`-+- policy='service-time 0' prio=50 status=active
  |- 2:0:0:0 sdc 8:32 active ready running
  `- 3:0:0:0 sdd 8:48 active ready running

Discovery found both portals, there are two sessions, and multipath joined sdc and sdd into mpatha. Your device letters and WWID will differ.

4Format and mount the multipath device

Run this:

az vm run-command invoke --resource-group rg-saat-l57 --name vm-init --command-id RunShellScript --scripts 'mkfs.ext4 -q /dev/mapper/mpatha; mkdir -p /data; mount /dev/mapper/mpatha /data; echo hello from iscsi > /data/test.txt; df -h /data | tail -1' --query "value[0].message" -o tsv

You should see something like this:

[stdout]
/dev/mapper/mpatha  3.9G   24K  3.7G   1% /data

✅ Checkpoint: vm-init has two iSCSI sessions, one multipath device mpatha, and a file system mounted on /data.