How do I prepare a proper cloud-init image for CentOS 7?

[chrigiboy]

Hello,

I want to prepare a cloud-init image, which is able to resize (grow) the HDD space and partitions. While it can grow the actual HDD space, it is not able to grow the partition.. I'm not sure, what I'm doing wrong... Is there a good tutorial about preparing a CentOS Cloud-Init image?