That is correct! You can implement your own plugin using the SPI that you've linked. That blog post is probably the most comprehensive place to start, and the docs on the SPI github are pretty solid as well. The Javadocs for the SPI can be found here:
https://cloudera.github.io/director-spi/apidocs/I'm not totally sure what you mean by which things you need to consider to build the plugin. To try to answer generally, other than the docs you've supplied, pay attention to the Javadocs for the various functions that need to be implemented. As an example:
https://cloudera.github.io/director-spi/apidocs/com/cloudera/director/spi/v1/provider/ResourceProvid...) Check out the Javadoc for the allocate function. Director expects that this be followed closely, e.g. Director expects that the plugin will clean up after itself upon failure.
Does that cover things, or is there anything else you'd like clarification on?
