azure-migrate-standard-to-basic.sh

#!/bin/bash 
# $1 - VM name
# $2 - resoure group 
# Overcomplicated solution for https://funinit.wordpress.com/2018/05/03/resizing-vms-in-azure-sequel/
# Basically change the VM disk from Premium to Standard SKU to allow resize to Basic tier
# Assume one VM in Resource group
# Assume VM has one disk

NAME=$1
GROUP=$2

#Gather information from OLD VM
echo "Get vmDiskSize"
diskId=$(az vm show -g $GROUP --name $NAME --query storageProfile.osDisk.managedDisk.id -o tsv)
echo "diskId=$diskId"
vmDiskSize=$(az disk show --id $diskId --query diskSizeGb -o tsv)
echo "vmDiskSize=$vmDiskSize"
echo "Get osType"
osType=$(az vm show  -g $GROUP -n $NAME --query storageProfile.osDisk.osType  -o tsv)
echo "osType=$osType"
echo "Get vmDisk"
vmDisk=$(az disk show  --id $diskId --query "name" -o tsv )
echo "vmDisk=$vmDisk"
echo "Get oldIpAddress"
oldIpAddress=$(az vm list-ip-addresses -n $NAME -g $GROUP --query [].virtualMachine.network.privateIpAddresses -o tsv)
snapName=${1}-snap

#Create a VM disk snapshot
echo "Create snapshot"
az snapshot create -g $GROUP -n $snapName --source $vmDisk
if [ $? -ne 0 ]
then
        exit 1
fi
snapshotId=$(az snapshot show --name $snapName --resource-group $GROUP --query [id] -o tsv)

#Create new DISK
newDiskName=${1}-StandardDisk
az disk create --resource-group $GROUP --name $newDiskName --sku Standard_LRS  --source $snapshotId --size-gb $vmDiskSize

#Stop the VM to reuse IP address
echo "Stop old VM"
az vm stop -n $NAME -g $GROUP
nicId=$(az vm nic list  -g $GROUP --vm-name $1 --query [].id -o tsv)
echo "nicId=$nicId"

#It's not possible because VM must have at least one nic
#echo "Remove oldVM nic"
#az vm nic remove --vm-name $1 -g $GROUP --nics $nicId

az vm delete -n $NAME -g $GROUP --yes



#Create new VM
newVMNAME=${1}-Standard
az vm create --name $newVMNAME --resource-group $GROUP --attach-os-disk $newDiskName --os-type $osType --nics $nicId 

#Cleanup - remove snapshot
az snapshot delete --resource-group $GROUP --name $snamName 

az vm deallocate --name $newVMName --resource-group $GROUP
az vm resize --name $newVMNAME --resource-group $GROUP --size Basic_A1
az vm start --name $enwVMNAME -g $GROUP