I have a rancher node template defined that uses amazonec2_config, which I assume triggers docker-machine amazonec2 driver to execute, which provisions a new ec2 instance and installs docker when provisioning an AMI. The node template passes userdata as an argument. At what point during the provisioning process is the content passed in userdata executed? Is it before or after docker is installed? I'm asking because I want to pass some additional docker configuration information in (registry mirror, ulimits and other properties) that get setup with content passed with userdata.