To say that Kubernetes uses a bit of YAML is like saying that a few people put some of their code on GitHub – accurate, but severely understated. Kubernetes uses a LOT of YAML. It takes to get a namespace with a single-container deployment with a service, no volumes, no secrets, and no configuration. over 50 lines of YAML Keeping all that syntax straight can be daunting. Is that property a string or can it be a number? Does that collection get set as a map or a list? Who knows? knows. kubectl The online Kubernetes API Reference Documentation site is great, but can help us out here with its command: kubectl kubectl explain kubectl explain pod.spec.containers
kubectl explain deployments.metadata
kubectl explain secret.data Each of these invocations will spit out documentation about the specified bits of Kubernetes resource YAML. I use it all the time to remember which API group/version a given object type exists in: $ kubectl explain statefulsets | head -n2
KIND:     StatefulSet
VERSION:  apps/v1 Did you know that the keys in a ConfigMap's attribute must follow a strict format? Or that non-UTF-8 configuration values are supposed to go in a different top-level attribute altogether? does: data kubectl explain $ kubectl configmap.data
KIND:     ConfigMap :  v1 : < [ ] >

DESCRIPTION: contains the configuration data. must consist alphanumeric , , . non-UTF sequences must the BinaryData field. The must overlap the the BinaryData , this during process. explain VERSION FIELD data map string string Data Each key of characters '-' '_' or '.' Values with -8 byte use keys stored in Data not with keys in field is enforced validation I have a tough time remembering what things are specified as lists, and what things are specified as keyed maps. Is a container's set of mounted volumes an array? An object? With , I no longer have to remember: explain kubectl pod.spec.containers.volumeMounts
KIND:     Pod :  v1 : volumeMounts <[] >

DESCRIPTION:
     Pod volumes the explain VERSION RESOURCE Object to mount into container 's filesystem. Cannot be updated.

     VolumeMount describes a mounting of a Volume within a container.
     
... etc. ... Even though is a list, you don't have to worry about that when referencing it to its sub-fields. This is in contrast to JSON path expressions and Go Templates. It's so handy (and transparent!) that I had to point this out, explicitly! Note: pod.spec.containers through If you like that, check out the accompanying video which goes into a bit more depth: The next tip will help you figure out what images you're running in production. Previously published at https://www.starkandwayne.com/blog/silly-kubectl-trick-1-explain-yourself-kubernetes/

Kubernetes Explained Simply: #1 Kubectl Hack

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