This might be useful for you: Marketplaces — OpenNebula 6.2.0 documentation. Note that if you execute the one_entrypoint.sh as stated in the docs it will be executed everytime the microVM boots, which for some cases might not be the requried behavior.
Yes, if you’re using the community edition this was included for OpenNebula 6.2.
how are the EXPOSE docker statements applied to container deployed on firecracker?
Note that when deploying docker images as Firecracker MicroVMs you’re not deploying a container but a (micro)VM. Hence no port needs to be exposed, if any service is started automatically when the microVM is deployed it will be listening there. If need it, you can manage networking access to the microVM using Security Groups.