kubectl Cheatsheet - Pods, Deploy, Logs & Apply Commands

A kubectl command reference for app developers and cluster operators, covering resource queries, Pod diagnosis, replica scaling, and cluster context management. Unlike reading YAML directly, kubectl is the consistent window into cluster state and change control, letting you quickly localize frequent incidents such as CrashLoopBackOff, Pods stuck in Pending, and failed rollouts. By the end you can run the whole loop yourself: inspect status → check events → read logs → recover or roll back.

Containers & Orchestration·46 commands·Last updated 2026-09-10

Typical Use Case

For Kubernetes ops and delivery: inspect resource status, scale and roll out updates, and troubleshoot Pods stuck in Pending / CrashLoopBackOff / ImagePullBackOff, plus reading logs and events to find root causes.

Get Resources 5

kubectl get pods -n prod

List pods in a namespace

kubectl get pods -o wide

Show extra info: node and pod IP

kubectl get pods -A

List pods across all namespaces

kubectl get svc,ingress -n prod

Query Services and Ingresses at once

kubectl get events --sort-by=.lastTimestamp

Sort events by time, find scheduling/pull failures

Describe & Diagnose 5

kubectl describe pod <pod> -n prod

Check events, container status, probes for CrashLoop/Pending

kubectl logs <pod> -n prod

View pod logs

kubectl logs <pod> --previous

View logs from the previous crashed container, essential for CrashLoop

kubectl logs <pod> -c <container>

Logs for a specific container in a multi-container pod

kubectl exec -it <pod> -- sh

Shell into a pod container for debugging

Scale & Rollout 5

kubectl scale deploy/app --replicas=3

Adjust replica count

kubectl rollout status deploy/app

Check rolling update progress

kubectl rollout undo deploy/app

Rollback to previous version

kubectl set image deploy/app c=app:1.1

Update image to trigger rolling update

kubectl delete pod <pod>

Delete pod, controller recreates automatically

Context & Configuration 4

kubectl config get-contexts

List all cluster contexts

kubectl config use-context <ctx>

Switch current cluster context, essential for multi-cluster

kubectl config set-context --current --namespace=prod

Set default namespace, saves typing -n each time

kubectl top pod -n prod

View pod CPU/memory usage, requires metrics-server

FAQ 5

Q: How do I list pods across all namespaces?

A: kubectl get pods -A or kubectl get pods --all-namespaces lists pods in every namespace of the cluster.

Q: What is the difference between kubectl apply and kubectl create?

A: kubectl apply is declarative (recommended) and supports create and update; kubectl create is imperative and errors if the resource already exists.

Q: How do I view a pod log?

A: kubectl logs <pod> -n <namespace>; add -f to follow, or --previous to see the crashed container logs.

Q: How do I shell into a pod container?

A: kubectl exec -it <pod> -- sh (or /bin/bash); use -c <container> for multi-container pods.

Q: How do I check cluster node status?

A: kubectl get nodes lists all node statuses; kubectl describe node <name> shows detailed node info.

Debugging & Output Formatting (REQ-02 add-on) 22

kubectl get pods --field-selector=status.phase=Running

List only pods in Running phase

kubectl get nodes --selector='!node-role.kubernetes.io/control-plane'

List worker nodes only, excluding control plane

kubectl get pods --show-labels

Show all labels attached to pods

kubectl get services --sort-by=.metadata.name

List services sorted by name

kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

Sort pods by restart count to spot crashes

kubectl get pv --sort-by=.spec.capacity.storage

Sort persistent volumes by capacity

kubectl get nodes -o jsonpath={.items[*].status.addresses[?(@.type=="ExternalIP")].address}

Extract external IPs of all nodes

kubectl get secret my-secret -o go-template={{range $k,$v := .data}}{{$k}}:{{$v|base64decode}}{{end}}

Decode and print all secret key-values at once

kubectl get pods -A -o=custom-columns='DATA:spec.containers[*].image'

List every container image running in the cluster

kubectl get node -o custom-columns='NODE_NAME:.metadata.name,STATUS:.status.conditions[?(@.type=="Ready")].status'

Show node readiness via custom columns

kubectl diff -f ./my-manifest.yaml

Diff live state against the applied manifest

kubectl patch node k8s-node-1 -p {"spec":{"unschedulable":true}}

Partially update a node to unschedulable

kubectl patch deployment web --subresource=scale --type=merge -p {"spec":{"replicas":2}}

Change replicas through the scale subresource

kubectl replace --force -f ./pod.json

Force replace a resource (delete then create)

kubectl expose deployment web --port=80 --target-port=8000

Expose a workload as a Service

kubectl logs -f -l name=myLabel --all-containers

Stream logs of all containers by label

kubectl logs my-pod --previous

Show logs of the previous crashed instance

kubectl debug my-pod -it --image=busybox:1.28

Create an interactive debug container in a pod

kubectl debug node/my-node -it --image=busybox:1.28

Create a debugging session on a node

kubectl cluster-info dump --output-directory=/path/to/cluster-state

Dump cluster state snapshot to a directory

kubectl api-resources --verbs=list,get

List resource types supporting given verbs

kubectl run nginx --image=nginx --dry-run=client -o yaml > pod.yaml

Generate a pod manifest without creating it

Parameter matrix

参数	Effect	Example
`-n`	指定命名空间，避免操作默认空间	`kubectl -n prod get pods`
`-o`	输出格式（yaml/json/wide/name）	`kubectl get pod web -o yaml`
`--kubeconfig`	指定集群凭证文件	`kubectl --kubeconfig ~/.kube/prod get nodes`
`-f`	按 YAML 文件创建/应用/删除资源	`kubectl apply -f deploy.yaml`
`--dry-run=client`	仅校验不创建，可生成清单	`kubectl run nginx --image=nginx --dry-run=client -o yaml`
`-l`	按标签筛选资源	`kubectl get pods -l app=web`
`--previous`	查看上一次崩溃容器的日志	`kubectl logs web --previous`
`-c`	指定多容器 Pod 中的某个容器	`kubectl logs web -c app`
`--watch`	持续观察资源变化	`kubectl get pods --watch`
`--record`	记录变更原因到修订历史	`kubectl set image deploy/web app=new:1.1 --record`

Common pitfalls

SymptomPod 长时间处于 Pending。

Cause节点资源不足、没有匹配的节点（taint/亲和），或 PVC 无法绑定。

Fixkubectl describe pod 看 Events；检查节点资源（kubectl top nodes）与 PVC 状态；放宽资源请求或污点容忍。

SymptomPod 反复重启，状态 CrashLoopBackOff。

Cause应用启动即崩溃（配置错误、依赖未就绪、端口被占），或探针失败。

Fixkubectl logs web --previous 看上一次崩溃日志；kubectl describe pod 看 Last State 与 Events；修正启动命令或探针阈值。

Symptom镜像拉取失败，状态 ImagePullBackOff / ErrImagePull。

Cause镜像名/标签写错、私有仓库未配置 imagePullSecret、或节点无法访问仓库。

Fix核对镜像地址与 tag；为私有仓库配置 imagePullSecrets；在节点上手动 crictl pull 验证网络。

Symptomkubectl top 报错 metrics not available。

Cause集群未安装 metrics-server，不是命令写错。

Fix确认 metrics-server 已部署（kubectl get apiservice v1beta1.metrics.k8s.io）；安装后再用 top。

Symptom误在本地把资源改到了生产集群。

Cause当前 context 指向生产，操作时未确认集群。

Fix任何写操作前执行 kubectl config get-contexts 与 kubectl config current-context 确认；用别名或工具防止误操作。

Symptomapply 之后改动未生效。

Cause字段被其他控制器（如 HPA、Operator）覆盖，或字段不可变。

Fixkubectl get 看实际值；对不可变字段（如 selector）需删除重建；排查是否有 controller 在管理该资源。

Troubleshooting

1先看 Pod 状态与事件
kubectl describe pod web
Events 段通常有最直接的失败原因（FailedScheduling、BackOff、FailedMount 等）。
2读应用日志（含上一次崩溃）
kubectl logs web --previous -c app
CrashLoop 时当前容器已退出，必须加 --previous 才能看到崩溃前的输出。
3确认节点资源与调度
kubectl top nodes
Pending 多半是 CPU/内存不足或没有可调度节点。
4查看完整修订历史以便回滚
kubectl rollout history deploy/web
确认有可回滚版本后再 kubectl rollout undo deploy/web 回退。

Tips

Troubleshooting order: get for status → describe for events → logs for app errors, add --previous for CrashLoop.
Run kubectl config get-contexts first to confirm the current cluster to avoid accidental operations on production.
kubectl top errors usually mean metrics-server is not installed, not a command syntax issue.

Official References

Each command links to its official documentation below, so you can verify the latest usage and read deeper.

Kubernetes Docs

Maintained by LaoHand

Publicly updated on Sep 10, 2026, continuously proofread against official docs.

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