How to set value of keys which confd can retrieve through metadata service?

According to this thread ( Rancher Metadata > Store custom data in it ), the metadata service is read-only, but I saw a code piece in the docker image of elasticsearch-conf:v0.4.0 as below:

[template]
src = "plugins.tmpl"
dest = "/data/confd/plugins.txt"
keys = [
  "/elasticsearch/plugins/",
]

The question is, how to set value for the key "/elasticsearch/plugins/" in rancher-compose.yml file.

Thanks for your help and the amazing rancher.

@bigsan Sorry for the delayed response, but the engineer who works the most on these templates has been a bit busy. I’m trying to get him to take a look at this whenever he gets a chance.

Also, have you had a chance to look at the Metadata Service docs?

http://docs.rancher.com/rancher/metadata-service/