I'm working on composing yaml file for installing Elasticsearch via the ECK operator (CRD).
Its documented here - https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-elasticsearch-specification.html
As one goes through the sub-links, you will discover there are various pieces through which we can define the configuration of Elasticsearch.
The description of the CRD is contained here, but this is not easy to read - https://download.elastic.co/downloads/eck/1.0.0-beta1/all-in-one.yaml
I'm curious how do Kubernetes developers understand various constructs of yaml file for a given kubernetes resource ?
Docs
In general, if it's a standard resource, the best way is to consult the official documentation for all the fields of the resource.
You can do this with kubectl explain. For example:
kubectl explain deploy
kubectl explain deploy.spec
kubectl explain deploy.spec.templateYou can find the same information in the web-based API reference.
Boilerplate
For some resources, you can use kubectl create to generate the YAML for a basic version of the resource, which you can then use as a starting point for your own customisations.
For example:
kubectl create deployment --image=nginx mydep -o yaml --dry-run >mydep.yamlThis generates the YAML for a Deployment resource and saves it in a local file. You can then customise the resource from there.
The --dry-run option causes the generated resource definition to not be submitted to the API server (so it won't be created) and the -o yaml option outputs the generated definition of the resource in YAML format.
Other common resources for which this is possible include:
See kubectl create -h.