kubectl explain: API Resource Reference

💡 Quick Answer: kubectl explain pod.spec.containers shows field documentation inline. kubectl api-resources lists all available resource types with short names. kubectl explain deployment --recursive shows the full structure. Use explain during CKA exam instead of memorizing YAML — it’s your built-in reference.

The Problem

Kubernetes has hundreds of resource fields:

• Can’t remember exact YAML structure
• Don’t know which fields are required vs optional
• Need to discover API groups and versions
• Want to know field types and valid values

The Solution

kubectl explain

# Top-level resource
kubectl explain pod
# KIND:     Pod
# VERSION:  v1
# DESCRIPTION: Pod is a collection of containers...
# FIELDS:
#   apiVersion   <string>
#   kind         <string>
#   metadata     <ObjectMeta>
#   spec         <PodSpec>
#   status       <PodStatus>

# Drill into fields
kubectl explain pod.spec
kubectl explain pod.spec.containers
kubectl explain pod.spec.containers.resources
kubectl explain pod.spec.containers.resources.limits

# Specific field
kubectl explain pod.spec.containers.livenessProbe.httpGet
# FIELDS:
#   host   <string>
#   httpHeaders  <[]HTTPHeader>
#   path   <string>    - required
#   port   <IntOrString> - required
#   scheme <string>

# Full recursive tree
kubectl explain pod.spec --recursive
# Shows ALL fields in tree format (great for discovering options)

kubectl explain deployment.spec --recursive | head -50

kubectl api-resources

# All resource types
kubectl api-resources
# NAME                  SHORTNAMES   APIVERSION   NAMESPACED   KIND
# pods                  po           v1           true         Pod
# services              svc          v1           true         Service
# deployments           deploy       apps/v1      true         Deployment
# configmaps            cm           v1           true         ConfigMap
# secrets                            v1           true         Secret
# ...

# Short names save typing
kubectl get po          # pods
kubectl get svc         # services
kubectl get deploy      # deployments
kubectl get cm          # configmaps
kubectl get ns          # namespaces
kubectl get no          # nodes
kubectl get rs          # replicasets
kubectl get ds          # daemonsets
kubectl get sts         # statefulsets
kubectl get pv          # persistentvolumes
kubectl get pvc         # persistentvolumeclaims
kubectl get ing         # ingresses
kubectl get netpol      # networkpolicies
kubectl get sa          # serviceaccounts
kubectl get ep          # endpoints
kubectl get cj          # cronjobs
kubectl get hpa         # horizontalpodautoscalers

# Filter by API group
kubectl api-resources --api-group=apps
kubectl api-resources --api-group=batch
kubectl api-resources --api-group=networking.k8s.io
kubectl api-resources --api-group=rbac.authorization.k8s.io

# Only namespaced resources
kubectl api-resources --namespaced=true

# Only cluster-scoped resources
kubectl api-resources --namespaced=false

# Resources with specific verb
kubectl api-resources --verbs=list,get

kubectl api-versions

# All API versions
kubectl api-versions
# admissionregistration.k8s.io/v1
# apps/v1
# autoscaling/v1
# autoscaling/v2
# batch/v1
# certificates.k8s.io/v1
# networking.k8s.io/v1
# rbac.authorization.k8s.io/v1
# storage.k8s.io/v1
# v1
# ...

# Useful for knowing correct apiVersion in YAML

CKA Exam Workflow

# Step 1: "Create a NetworkPolicy" — what's the apiVersion?
kubectl api-resources | grep networkpol
# networkpolicies   netpol   networking.k8s.io/v1   true   NetworkPolicy

# Step 2: What fields are available?
kubectl explain networkpolicy.spec --recursive

# Step 3: What does ingress.from look like?
kubectl explain networkpolicy.spec.ingress.from

# Step 4: Generate starting YAML
kubectl create deployment nginx --image=nginx --dry-run=client -o yaml

# Much faster than memorizing every YAML structure!

Discover CRDs

# List Custom Resource Definitions
kubectl get crd
# NAME                                    CREATED AT
# certificates.cert-manager.io            2026-01-15
# ingressroutes.traefik.containo.us       2026-01-20

# Explain CRD fields
kubectl explain certificate.spec   # cert-manager Certificate

# API resources includes CRDs
kubectl api-resources | grep cert-manager

Raw API Access

# Direct API call
kubectl get --raw /api/v1/namespaces/default/pods

# API discovery
kubectl get --raw /apis

# Specific resource API
kubectl get --raw /apis/apps/v1

# OpenAPI spec
kubectl get --raw /openapi/v2 | head -100

Common Issues

“the server doesn’t have a resource type”

Resource not available in this cluster version, or CRD not installed. Check: kubectl api-resources | grep <name>.

Wrong apiVersion in YAML

Use kubectl api-resources to find the correct API group and version. Common mistake: extensions/v1beta1 (removed) instead of networking.k8s.io/v1.

Field not found in explain

May be in a newer K8s version. Check: kubectl version and K8s release notes.

Best Practices

• Use explain instead of Google during CKA — faster and always accurate
• --recursive for discovering available fields
• Short names for speed — po, svc, deploy, cm
• api-resources | grep to find the right apiVersion
• --dry-run=client -o yaml to generate starting templates

Key Takeaways

• kubectl explain <resource.field> is your inline documentation
• kubectl api-resources lists all resources with short names and API groups
• Use --recursive to see the full field tree
• Short names (po, svc, deploy) save typing
• Essential CKA skill — explain + dry-run = no memorization needed