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k8s:core:kind [2026/05/31 03:43] – phong2018k8s:core:kind [2026/05/31 04:07] (current) – [Here's the relationship diagram.] phong2018
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-====== Kubernetes kind: complete reference ======+====== Kubernetes ''kind'' Field — Complete Guide ======
  
-''kind'' tells Kubernetes what type of object to create. +===== Overview ===== 
-Each kind has its own controller, behavior, and lifecycle.+ 
 +In Kubernetes, every resource manifest (written in YAML or JSON) must declare four top-level fields: 
 + 
 +<code yaml> 
 +apiVersion: apps/v1 
 +kind: Deployment 
 +metadata: 
 +  name: my-app 
 +spec: 
 +  ... 
 +</code> 
 + 
 +The ''kind'' field tells Kubernetes **what type of resource** you are creating or managing. It maps to a specific API object within Kubernetes, and each kind has its own schema, behavior, and lifecycle.
  
 ---- ----
  
-===== ConfigMap =====+===== Core Resource Kinds =====
  
-Stores non-sensitive configuration data as key-value pairs. +==== 1. Pod ====
-Injected into Pods as environment variables or mounted as files.+
  
-**apiVersion:** ''v1''+The **smallest deployable unit** in Kubernetes. A Pod wraps one or more containers that share network and storage.
  
 <code yaml> <code yaml>
 apiVersion: v1 apiVersion: v1
-kind: ConfigMap+kind: Pod
 metadata: metadata:
-  name: app-config +  name: nginx-pod 
-  namespace: default +  labels: 
-data: +    app: nginx 
-  APP_ENV: "production" +spec: 
-  LOG_LEVEL: "info" +  containers: 
-  config.yaml: | +    - name: nginx 
-    timeout: 30 +      image: nginx:1.25 
-    retries: 3 +      ports: 
-    debug: false+        - containerPort: 80
 </code> </code>
  
-**Use as env vars:** +^ Field       ^ Description                                  ^ 
-<code yaml> +| ''kind''    | ''Pod'' — declares a single pod resource     | 
-envFrom: +| ''metadata'' | Name and labels for identifying the pod     | 
-  - configMapRef: +| ''spec.containers'' | List of containers inside the pod   | 
-      name: app-config + 
-</code>+> **Note:** Pods are rarely created directly. Use Deployments or StatefulSets instead for resilience. 
 + 
 +---- 
 + 
 +==== 2. Deployment ==== 
 + 
 +Manages a **ReplicaSet** to ensure a specified number of Pod replicas are running at all times. Supports rolling updates and rollbacks.
  
-**Use as mounted file:** 
 <code yaml> <code yaml>
-volumes: +apiVersion: apps/v1 
-  - name: config-vol +kind: Deployment 
-    configMap: +metadata: 
-      name: app-config +  name: web-app 
-volumeMounts: +  namespace: default 
-  - name: config-vol +spec: 
-    mountPath: /etc/config+  replicas: 3 
 +  selector: 
 +    matchLabels: 
 +      app: web-app 
 +  template: 
 +    metadata: 
 +      labels: 
 +        app: web-app 
 +    spec: 
 +      containers: 
 +        - name: web 
 +          image: nginx:1.25 
 +          ports: 
 +            - containerPort: 80
 </code> </code>
  
-> ''config.yaml'' appears as a real file at ''/etc/config/config.yaml'' inside the container. +^ Field         ^ Description                                          ^ 
- +| ''kind''      | ''Deployment'' — manages a set of identical pods     | 
-^ Field ^ Purpose ^ +| ''replicas''  | Number of desired Pod instances                      | 
-| ''data'' | Plain text key-value pairs | +| ''selector''  | Labels used to identify which Pods belong here       | 
-| ''binaryData'' | Base64-encoded binary data | +| ''template''  | Pod template used to create new Pods                 |
- +
-> Use case: app settings, feature flags, config files, environment differences (dev/staging/prod).+
  
 ---- ----
  
-===== Secret =====+==== 3. Service ====
  
-Stores sensitive data. Values are base64-encoded at rest. +Exposes a set of Pods as a **stable network endpoint**. Handles load balancing across all matching Pods.
-Works like ConfigMap but with access restrictions and audit logging. +
- +
-**apiVersion:** ''v1''+
  
 <code yaml> <code yaml>
 apiVersion: v1 apiVersion: v1
-kind: Secret+kind: Service
 metadata: metadata:
-  name: db-secret +  name: web-service 
-  namespace: default +spec: 
-type: Opaque +  selector: 
-data: +    app: web-app 
-  username: YWRtaW4=        # echo -n "admin" | base64 +  ports: 
-  password: c2VjcmV0MTIz    # echo -n "secret123" | base64+    - protocol: TCP 
 +      port: 80 
 +      targetPort: 80 
 +  type: ClusterIP
 </code> </code>
  
-**Secret types:**+^ Service Type    ^ Description                                              ^ 
 +| ''ClusterIP''   | Default. Internal cluster access only                    | 
 +| ''NodePort''    | Exposes on each node's IP at a static port               | 
 +| ''LoadBalancer'' | Creates an external load balancer (cloud providers)     | 
 +| ''ExternalName'' | Maps to an external DNS name                            | 
 + 
 +---- 
 + 
 +==== 4. ConfigMap ====
  
-^ Type ^ Use case ^ +Stores **non-sensitive configuration** as key-value pairs, decoupling config from container images.
-| ''Opaque'' | General-purpose (default) | +
-| ''kubernetes.io/tls'' | TLS certificates (tls.crt + tls.key) | +
-| ''kubernetes.io/dockerconfigjson'' | Docker registry credentials | +
-| ''kubernetes.io/service-account-token'' | ServiceAccount tokens | +
-| ''kubernetes.io/basic-auth'' | Basic username/password | +
-| ''kubernetes.io/ssh-auth'' | SSH private key |+
  
-**TLS Secret example:** 
 <code yaml> <code yaml>
 apiVersion: v1 apiVersion: v1
-kind: Secret+kind: ConfigMap
 metadata: metadata:
-  name: tls-secret +  name: app-config
-type: kubernetes.io/tls+
 data: data:
-  tls.crt: <base64-encoded-cert> +  APP_ENV: production 
-  tls.key: <base64-encoded-key>+  APP_PORT: "8080" 
 +  log_level: info
 </code> </code>
  
-**Use in Pod:**+Use in a Pod: 
 <code yaml> <code yaml>
-env: +envFrom: 
-  - name: DB_PASSWORD +  - configMapRef: 
-    valueFrom: +      name: app-config
-      secretKeyRef: +
-        name: db-secret +
-        key: password+
 </code> </code>
- 
-> Use case: passwords, API keys, TLS certs, Docker pull credentials. 
- 
-<note warning> 
-Base64 is encoding, NOT encryption. Use tools like Sealed Secrets or Vault for real encryption at rest. 
-</note> 
  
 ---- ----
  
-===== Namespace =====+==== 5. Secret ====
  
-Logical partition inside a cluster. +Like ConfigMap, but for **sensitive data** (passwords, tokens, TLS certs). Values are base64-encoded.
-Isolates resources between teams, environments, or projects. +
- +
-**apiVersion:** ''v1''+
  
 <code yaml> <code yaml>
 apiVersion: v1 apiVersion: v1
-kind: Namespace+kind: Secret
 metadata: metadata:
-  name: team-backend +  name: db-credentials 
-  labels: +type: Opaque 
-    team: backend +data: 
-    env: production+  username: YWRtaW4=        # base64 of "admin" 
 +  password: cGFzc3dvcmQ=   # base64 of "password"
 </code> </code>
  
-**Built-in namespaces:**+> **Security note:** base64 is encoding, not encryption. Use tools like Sealed Secrets or Vault for production.
  
-^ Namespace ^ Purpose ^ +---- 
-| ''default'' | Resources with no namespace specified go here | + 
-| ''kube-system'' | Core Kubernetes components (DNS, scheduler, controller-manager) | +==== 6. StatefulSet ==== 
-| ''kube-public'' | Publicly readable data (cluster info) | + 
-| ''kube-node-lease'' | Node heartbeat lease objects |+Like Deployment, but designed for **stateful applications** (databases, message queues) that need: 
 +  * Stable, persistent network identity 
 +  * Ordered, graceful deployment and scaling 
 +  * Persistent storage per pod
  
-**Deploy to a namespace:** 
 <code yaml> <code yaml>
 +apiVersion: apps/v1
 +kind: StatefulSet
 metadata: metadata:
-  name: my-app +  name: mysql 
-  namespace: team-backend+spec: 
 +  serviceName: "mysql" 
 +  replicas: 3 
 +  selector: 
 +    matchLabels: 
 +      app: mysql 
 +  template: 
 +    metadata: 
 +      labels: 
 +        app: mysql 
 +    spec: 
 +      containers: 
 +        - name: mysql 
 +          image: mysql:8.0 
 +          env: 
 +            - name: MYSQL_ROOT_PASSWORD 
 +              value: "secret" 
 +          volumeMounts: 
 +            - name: data 
 +              mountPath: /var/lib/mysql 
 +  volumeClaimTemplates: 
 +    - metadata: 
 +        name: data 
 +      spec: 
 +        accessModes: ["ReadWriteOnce"] 
 +        resources: 
 +          requests: 
 +            storage: 10Gi
 </code> </code>
  
-**Namespace-scoped vs cluster-scoped:**+----
  
-^ Namespace-scoped ^ Cluster-scoped ^ +==== 7. DaemonSet ====
-| Pod, Deployment, Service | Node, PersistentVolume | +
-| ConfigMap, Secret | ClusterRole, StorageClass | +
-| Role, RoleBinding | Namespace itself |+
  
-> Use case: isolate dev/staging/prod, separate teams, apply ResourceQuota per namespace.+Ensures a **copy of a Pod runs on every node** (or selected nodes). Used for cluster-level services like log collectors, monitoring agents, or network plugins. 
 + 
 +<code yaml> 
 +apiVersion: apps/v1 
 +kind: DaemonSet 
 +metadata: 
 +  name: fluentd 
 +spec: 
 +  selector: 
 +    matchLabels: 
 +      name: fluentd 
 +  template: 
 +    metadata: 
 +      labels: 
 +        name: fluentd 
 +    spec: 
 +      containers: 
 +        - name: fluentd 
 +          image: fluent/fluentd:v1.16 
 +</code>
  
 ---- ----
  
-===== Job =====+==== 8. Job ====
  
-Runs a Pod to completion. Guarantees the task finishes successfully. +Runs a **one-off task** to completion. Kubernetes ensures the Pod runs successfully at least once.
-Retries automatically on failure. +
- +
-**apiVersion:** ''batch/v1''+
  
 <code yaml> <code yaml>
Line 171: Line 233:
   name: db-migration   name: db-migration
 spec: spec:
-  completions: 1         # how many successful completions needed 
-  parallelism: 1         # how many Pods run at the same time 
-  backoffLimit: 4        # retry up to 4 times on failure 
   template:   template:
     spec:     spec:
       containers:       containers:
         - name: migrate         - name: migrate
-          image: myapp:v2+          image: myapp:latest
           command: ["python", "manage.py", "migrate"]           command: ["python", "manage.py", "migrate"]
-      restartPolicy: OnFailure   # required: Never or OnFailure+      restartPolicy: OnFailure
 </code> </code>
- 
-**Parallel Job example (process 5 items, 2 at a time):** 
-<code yaml> 
-spec: 
-  completions: 5 
-  parallelism: 2 
-</code> 
- 
-^ Field ^ Purpose ^ 
-| ''completions'' | Total successful Pods needed to finish the Job | 
-| ''parallelism'' | Max Pods running simultaneously | 
-| ''backoffLimit'' | Max retries before Job is marked failed | 
-| ''activeDeadlineSeconds'' | Kill Job if it runs longer than N seconds | 
-| ''ttlSecondsAfterFinished'' | Auto-delete Job N seconds after completion | 
- 
-> Use case: database migrations, data imports, report generation, ML training runs, batch processing. 
  
 ---- ----
  
-===== CronJob ===== +==== 9. CronJob ====
- +
-Runs a Job on a time-based schedule. Same as Linux ''cron''.+
  
-**apiVersion:** ''batch/v1''+Runs Jobs on a **scheduled (cron) basis**.
  
 <code yaml> <code yaml>
Line 211: Line 252:
 kind: CronJob kind: CronJob
 metadata: metadata:
-  name: nightly-backup+  name: backup-job
 spec: spec:
-  schedule: "0 2 * * *"            # every day at 02:00 +  schedule: "0 2 * * *"   # Every day at 2:00 AM
-  timeZone: "Asia/Ho_Chi_Minh"     # optional, requires k8s 1.27+ +
-  concurrencyPolicy: Forbid         # don't run if previous is still running +
-  successfulJobsHistoryLimit: 3 +
-  failedJobsHistoryLimit: 1+
   jobTemplate:   jobTemplate:
     spec:     spec:
Line 225: Line 262:
             - name: backup             - name: backup
               image: backup-tool:latest               image: backup-tool:latest
-              command: ["sh", "-c", "/scripts/backup.sh"]+              command: ["/bin/sh", "-c", "run-backup.sh"]
           restartPolicy: OnFailure           restartPolicy: OnFailure
 </code> </code>
  
-**Cron syntax:** +----
-<code> +
-┌───── minute (0-59) +
-│ ┌─── hour (0-23) +
-│ │ ┌─ day of month (1-31) +
-│ │ │ ┌ month (1-12) +
-│ │ │ │ ┌ day of week (0-6, Sun=0) +
-│ │ │ │ │ +
-* * * * *+
  
-Examples: +==== 10. Namespace ==== 
-"0 2 * * *"     → every day at 02:00 + 
-"*/15 * * * *"  → every 15 minutes +Creates a **virtual cluster** within a Kubernetes cluster, providing isolation between teams or environments. 
-"0 9 * * 1"     → every Monday at 09:00 + 
-"0 0 1 * *"     → first day of every month at midnight+<code yaml> 
 +apiVersion: v1 
 +kind: Namespace 
 +metadata: 
 +  name: staging
 </code> </code>
  
-**concurrencyPolicy values:**+----
  
-^ Value ^ Behavior ^ +==== 11. PersistentVolumeClaim (PVC) ====
-| ''Allow'' | Run overlapping Jobs (default) | +
-| ''Forbid'' | Skip new Job if previous still running | +
-| ''Replace'' | Cancel previous Job, start new one |+
  
-> Use case: backups, log rotation, cleanup tasks, scheduled reports, cache warming.+Requests **persistent storage** from the cluster for a Pod. 
 + 
 +<code yaml> 
 +apiVersion: v1 
 +kind: PersistentVolumeClaim 
 +metadata: 
 +  name: my-storage 
 +spec: 
 +  accessModes: 
 +    - ReadWriteOnce 
 +  resources: 
 +    requests: 
 +      storage: 5Gi 
 +</code>
  
 ---- ----
  
-===== Ingress =====+==== 12. Ingress ====
  
-HTTP/HTTPS routing rules. +Manages **external HTTP/HTTPS access** to services, routing rules, TLS termination.
-Routes external traffic to internal Services based on hostname or URL path. +
-Requires an Ingress Controller (nginx, traefik, etc.) to be installed. +
- +
-**apiVersion:** ''networking.k8s.io/v1''+
  
 <code yaml> <code yaml>
Line 269: Line 308:
 kind: Ingress kind: Ingress
 metadata: metadata:
-  name: main-ingress+  name: web-ingress
   annotations:   annotations:
     nginx.ingress.kubernetes.io/rewrite-target: /     nginx.ingress.kubernetes.io/rewrite-target: /
 spec: spec:
-  ingressClassName: nginx 
-  tls: 
-    - hosts: 
-        - myapp.example.com 
-      secretName: tls-secret        # Secret of type kubernetes.io/tls 
   rules:   rules:
     - host: myapp.example.com     - host: myapp.example.com
       http:       http:
         paths:         paths:
-          - path: /api 
-            pathType: Prefix 
-            backend: 
-              service: 
-                name: api-service 
-                port: 
-                  number: 8080 
           - path: /           - path: /
             pathType: Prefix             pathType: Prefix
             backend:             backend:
               service:               service:
-                name: frontend-service+                name: web-service
                 port:                 port:
                   number: 80                   number: 80
 </code> </code>
- 
-**pathType values:** 
- 
-^ Value ^ Behavior ^ 
-| ''Exact'' | Match exact path only (e.g. ''/api'' only) | 
-| ''Prefix'' | Match path and all sub-paths (e.g. ''/api/v1'', ''/api/v2'') | 
-| ''ImplementationSpecific'' | Behavior depends on Ingress Controller | 
- 
-**Traffic flow:** 
-<code> 
-Client 
-  └── Ingress Controller (nginx/traefik) 
-        └── Ingress rules 
-              ├── /api   → api-service → api Pods 
-              └── /      → frontend-service → frontend Pods 
-</code> 
- 
-> Use case: expose multiple services under one domain, TLS termination, path-based routing, virtual hosting. 
  
 ---- ----
  
-===== ClusterRole =====+===== Summary Table =====
  
-Defines permissions that apply cluster-wide (all namespaces + cluster-scoped resources). +^ Kind                   ^ API Version         ^ Purpose                                      ^ 
-Part of Kubernetes RBAC (Role-Based Access Control). +| ''Pod''                | ''v1''              | Smallest deployable unit                     | 
- +| ''Deployment''         | ''apps/v1''         | Stateless app, rolling updates               | 
-**apiVersion:** ''rbac.authorization.k8s.io/v1'' +| ''StatefulSet''        | ''apps/v1''         | Stateful app with stable identity            | 
- +| ''DaemonSet''          | ''apps/v1''         | One pod per node                             | 
-<code yaml> +| ''Job''                | ''batch/v1''        | One-off task                                 | 
-apiVersion: rbac.authorization.k8s.io/v1 +| ''CronJob''            | ''batch/v1''        | Scheduled recurring task                     | 
-kind: ClusterRole +| ''Service''            | ''v1''              | Network endpoint for pods                    | 
-metadata: +| ''Ingress''            | ''networking.k8s.io/v1'' | HTTP routing / TLS termination         | 
-  name: pod-reader +| ''ConfigMap''          | ''v1''              | Non-sensitive config data                    | 
-rules: +| ''Secret''             | ''v1''              | Sensitive config data                        | 
-  - apiGroups: [""]             # "" = core API group +| ''Namespace''          | ''v1''              | Cluster isolation                            | 
-    resources: ["pods", "pods/log"] +| ''PersistentVolumeClaim'' | ''v1''           | Request for persistent storage               |
-    verbs: ["get", "list", "watch"] +
-  - apiGroups: ["apps"] +
-    resources: ["deployments"] +
-    verbs: ["get", "list", "watch", "create", "update", "patch"] +
-  - apiGroups: [""] +
-    resources: ["nodes"]        # cluster-scoped — only ClusterRole can grant this +
-    verbs: ["get", "list"] +
-</code> +
- +
-**All available verbs:** +
- +
-^ Verb ^ HTTP method equivalent ^ +
-| ''get'' | GET (single resource) | +
-| ''list'' | GET (collection) | +
-| ''watch'' | GET with ?watch=true (streaming) | +
-| ''create'' | POST | +
-| ''update'' | PUT | +
-| ''patch'' | PATCH | +
-| ''delete'' | DELETE | +
-| ''deletecollection'' | DELETE (collection) | +
- +
-**Wildcard (grant all):** +
-<code yaml> +
-rules: +
-  - apiGroups: ["*"] +
-    resources: ["*"] +
-    verbs: ["*"] +
-</code> +
- +
-**ClusterRole vs Role:** +
- +
-^ ^ Role ^ ClusterRole ^ +
-| Scope | Single namespace | All namespaces + cluster resources | +
-| Can access Nodes | No | Yes | +
-| Can access PersistentVolumes | No | Yes | +
-| Bound with | RoleBinding | ClusterRoleBinding (or RoleBinding) | +
- +
-> Use case: read-only cluster monitoring, CI/CD pipelines, operators, admin access. +
- +
-<note> +
-ClusterRole alone does nothing. It must be bound via ''ClusterRoleBinding'' or ''RoleBinding''. +
-</note>+
  
 ---- ----
  
-===== ClusterRoleBinding =====+===== How ''kind'' Connects to ''apiVersion'' =====
  
-Grants a ClusterRole to a user, group, or ServiceAccount across the entire cluster.+The ''apiVersion'' determines which API group and version handles your ''kind'':
  
-**apiVersion:** ''rbac.authorization.k8s.io/v1'' +^ apiVersion              ^ Kinds included                                       ^ 
- +| ''v1''                  | Pod, Service, ConfigMap, Secret, Namespace, PVC      | 
-<code yaml> +| ''apps/v1''             | Deployment, StatefulSet, DaemonSet, ReplicaSet       | 
-apiVersion: rbac.authorization.k8s.io/v1 +| ''batch/v1''            | Job, CronJob                                         | 
-kind: ClusterRoleBinding +| ''networking.k8s.io/v1'' | Ingress, NetworkPolicy                              | 
-metadata: +| ''rbac.authorization.k8s.io/v1'' | Role, ClusterRole, RoleBinding           |
-  name: pod-reader-binding +
-subjects: +
-  - kind: ServiceAccount +
-    name: monitoring-agent +
-    namespace: monitoring +
-  - kind: User +
-    name: jane@example.com +
-    apiGroup: rbac.authorization.k8s.io +
-  - kind: Group +
-    name: devops-team +
-    apiGroup: rbac.authorization.k8s.io +
-roleRef: +
-  kind: ClusterRole +
-  name: pod-reader +
-  apiGroup: rbac.authorization.k8s.io +
-</code> +
- +
-**subjects kinds:** +
- +
-^ Kind ^ Example ^ +
-| ''ServiceAccount'' | Pod identity inside cluster | +
-| ''User'' | Human user (managed externally) | +
-| ''Group'' | Group of users | +
- +
-> Use case: grant monitoring agent read access to all Pods cluster-wide.+
  
 ---- ----
  
-===== HorizontalPodAutoscaler =====+===== Here's the relationship diagram. =====  
 +Hierarchy flows top-down:
  
-Automatically scales Pod count up or down based on metrics. +Deployment → ReplicaSet → Pod (Deployment manages replicas, which manage pods)
-Watches a target (Deployment, StatefulSet) and adjusts ''replicas''.+
  
-**apiVersion:** ''autoscaling/v2''+StatefulSet and DaemonSet go straight to their own Pods
  
-<code yaml> +CronJob → Job (CronJob triggers Jobs on a schedule)
-apiVersion: autoscaling/v2 +
-kind: HorizontalPodAutoscaler +
-metadata: +
-  name: web-hpa +
-spec: +
-  scaleTargetRef: +
-    apiVersion: apps/v1 +
-    kind: Deployment +
-    name: web-app +
-  minReplicas: 2 +
-  maxReplicas: 20 +
-  metrics: +
-    - type: Resource +
-      resource: +
-        name: cpu +
-        target: +
-          type: Utilization +
-          averageUtilization: 70     # scale up if avg CPU > 70% +
-    - type: Resource +
-      resource: +
-        name: memory +
-        target: +
-          type: AverageValue +
-          averageValue: 512Mi +
-</code>+
  
-**Custom metrics example (requests per second):** +Networking routes traffic inward:
-<code yaml> +
-metrics: +
-  - type: Pods +
-    pods: +
-      metric: +
-        name: requests_per_second +
-      target: +
-        type: AverageValue +
-        averageValue: "1000" +
-</code>+
  
-**Scale behavior (control speed of scaling):** +Ingress → Service → Pod (external HTTP traffic funneled down to running containers)
-<code yaml> +
-behavior: +
-  scaleUp: +
-    stabilizationWindowSeconds: 0       # scale up immediately +
-    policies: +
-      - type: Pods +
-        value: 4 +
-        periodSeconds: 60               # add max 4 pods per minute +
-  scaleDown: +
-    stabilizationWindowSeconds: 300     # wait 5 min before scaling down +
-</code>+
  
-^ Field ^ Purpose ^ +NetworkPolicy applies traffic rules at the Pod level
-| ''minReplicas'' | Never go below this count | +
-| ''maxReplicas'' | Never exceed this count | +
-| ''averageUtilization'' | Target CPU/memory percentage across all Pods | +
-| ''stabilizationWindowSeconds'' | Cooldown window to prevent flapping |+
  
-**How it works:** +Config and Storage are mounted into Pods:
-<code> +
-Metrics Server +
-  └── HPA checks metrics every 15s +
-        ├── CPU > 70%  → scale UP   (add Pods) +
-        └── CPU < 70%  → scale DOWN (remove Pods) +
-              └── Deployment adjusts replicas +
-</code>+
  
-> Use case: web traffic spikes, variable batch load, cost optimization (scale down at night).+ConfigMap and Secret are injected as env vars or volume mounts (dashed lines)
  
-<note important> +PVC (PersistentVolumeClaim) binds to a PV (PersistentVolume) and mounts into Pods
-HPA requires Metrics Server installed in the cluster. Resource requests must be set on containers for CPU/memory HPA to work. +
-</note>+
  
-----+Everything lives inside a `Namespace for isolation.
  
-===== Quick comparison ===== +{{ :k8s:core:kind-in-kubenetes.png?600 |}}
- +
-^ Kind ^ apiVersion ^ Scope ^ Controller ^ +
-| ''ConfigMap'' | ''v1'' | Namespace | — | +
-| ''Secret'' | ''v1'' | Namespace | — | +
-| ''Namespace'' | ''v1'' | Cluster | — | +
-| ''Job'' | ''batch/v1'' | Namespace | Job Controller | +
-| ''CronJob'' | ''batch/v1'' | Namespace | CronJob Controller | +
-| ''Ingress'' | ''networking.k8s.io/v1'' | Namespace | Ingress Controller | +
-| ''ClusterRole'' | ''rbac.authorization.k8s.io/v1'' | Cluster | — | +
-| ''ClusterRoleBinding'' | ''rbac.authorization.k8s.io/v1'' | Cluster | — | +
-| ''HorizontalPodAutoscaler'' | ''autoscaling/v2'' | Namespace | HPA Controller | +
- +
-----+
  
-===== Key rule =====+===== See Also =====
  
-<note important> +  * [[https://kubernetes.io/docs/concepts/|Kubernetes Concepts]] 
-Every ''kind'' requires a matching ''apiVersion''. +  * [[https://kubernetes.io/docs/reference/kubernetes-api/|Kubernetes API Reference]] 
-Wrong ''apiVersion'' = object creation fails, even if all other fields are correct. +  * ''kubectl api-resources'' — list all available kinds in your cluster
-</note>+
k8s/core/kind.1780198981.txt.gz · Last modified: by phong2018