Wednesday, 28 June 2017

Shell Script To Create VMs From Command Line

While I agree PowerCLI API's are the right way to deploy multiple VMs on an ESXi, I had to fallback to bash script for a project that I have been working on lately. The script is pretty simple. It is divided into 6 functions.

Function 1 is for a VMX file template which has variable input obtained from the remaining functions
Function 2 is for creating a VMDK of required size and provision type
Function 3 is for MAC address generation
Function 4 is VM Uid and VC Uid generation
Function 5 is VM Registration
Function 6 is for VM Power On

Let's have a look at this:

While ESXi does not run "bash" I had to go with the #!/bin/sh shebang to define the interpreter.
The VMX file function has a pre created template with certain options that has a variable input which can be modified by the user later while executing the script:

Create_VM ()
read -p "Enter the VM name: " VM_name
read -p "Enter the path of the datastore. /vmfs/volumes/<storage-name>/: " datastore_name
cd /vmfs/volumes/$datastore_name
mkdir $VM_name && cd $VM_name && touch $VM_name.vmx
read -p "Enter the Hardware version for the VM: " HW_version
read -p "Enter the Memory required for the VM: " Memory
read -p "Enter the network type, e1000 / VMXNET3: " Net_type
read -p "Enter the VM Port group name: " Port_group
# VMX File Entries
cat << EOF > $VM_name.vmx
.encoding = "UTF-8"
config.version = "8"
virtualHW.version = "$HW_version"
nvram = "$VM_name.nvram"
pciBridge0.present = "TRUE"
svga.present = "TRUE"
pciBridge4.present = "TRUE"
pciBridge4.virtualDev = "pcieRootPort"
pciBridge4.functions = "8"
pciBridge5.present = "TRUE"
pciBridge5.virtualDev = "pcieRootPort"
pciBridge5.functions = "8"
pciBridge6.present = "TRUE"
pciBridge6.virtualDev = "pcieRootPort"
pciBridge6.functions = "8"
pciBridge7.present = "TRUE"
pciBridge7.virtualDev = "pcieRootPort"
pciBridge7.functions = "8"
vmci0.present = "TRUE"
hpet0.present = "TRUE"
memSize = "$Memory"
scsi0.virtualDev = "lsisas1068"
scsi0.present = "TRUE"
ide1:0.startConnected = "FALSE"
ide1:0.deviceType = "cdrom-raw"
ide1:0.clientDevice = "TRUE"
ide1:0.fileName = "emptyBackingString"
ide1:0.present = "TRUE"
floppy0.startConnected = "FALSE"
floppy0.clientDevice = "TRUE"
floppy0.fileName = "vmware-null-remote-floppy"
ethernet0.virtualDev = "$Net_type"
ethernet0.networkName = "$Port_group"
ethernet0.checkMACAddress = "false"
ethernet0.addressType = "static"
ethernet0.Address = "$final_mac"
ethernet0.present = "TRUE"
scsi0:0.deviceType = "scsi-hardDisk"
scsi0:0.fileName = "$VM_name.vmdk"
scsi0:0.present = "TRUE"
displayName = "$VM_name"
guestOS = "windows8srv-64"
disk.EnableUUID = "TRUE"
toolScripts.afterPowerOn = "TRUE"
toolScripts.afterResume = "TRUE"
toolScripts.beforeSuspend = "TRUE"
toolScripts.beforePowerOff = "TRUE"
uuid.bios = "$uuid"
vc.uuid = "$vcid"
ctkEnabled = "TRUE"
scsi0:0.ctkEnabled = "TRUE"

The create VMDK is simple which uses the vmkfstools -C to get the job done.

Create_VMDK ()
read -p "Enter disk format. thin / zeroedthick / eagerzeroedthick: " format
read -p "Enter size: " size
vmkfstools -c "$size"G -d $format $VM_name.vmdk

The MAC address generation keeps a static MAC by modifying the VMX and the constant VMware defined prefix with a random generated number for the last octet.

MAC_address ()
mac=$(awk -v min=1000 -v max=9000 'BEGIN{srand(); print int(min+rand()*(max-min+1))}' | sed -e 's/.\{2\}/&:/g;s/.$//')

The similar algorithm is applied for VC UUid generation where the post digits are constant only the first octet is changed.

UUID_generate ()
uuid_postfix="1a c2 4e fe 1a 8c d2-db 90 02 81 ce d8 31 15"
vcid_postfix="1a c9 91 4b 4a b9 93-79 23 12 1f b2 c5 37 f8"
uuid_prefix=$(awk -v min=10 -v max=99 'BEGIN{srand(); print int(min+rand()*(max-min+1))}')
vcid_prefix=$(awk -v min=10 -v max=99 'BEGIN{srand(); print int(min+rand()*(max-min+1))}')
uuid="$uuid_prefix $uuid_postfix"
vcid="$vcid_prefix $vcid_postfix"

The complete source code{} can be accessed here:

A while loop is defined if a user wants to deploy multiple VMs.

Well, that's pretty much it.


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