customData

Specifies a base-64 encoded string of custom data. The base-64 encoded string is decoded to a binary array that is saved as a file on the virtual machine. The maximum length of the binary array is 65535 bytes.

Note: Do not pass any secrets or passwords in customData property

This property cannot be updated after the VM is created.

customData is passed to the VM to be saved as a file. For more information see Custom Data on Azure VMs

For using cloud-init for your Linux VM, see Using cloud-init to customize a Linux VM during creation