kubectl 简明手册（二）（Cheat Sheet）

资源扩展 Scaling resources

kubectl scale --replicas=3 rs/foo                                 # Scale a replicaset named 'foo' to 3

kubectl scale --replicas=3 -f foo.yaml                            # Scale a resource specified in "foo.yaml" to 3

kubectl scale --current-replicas=2 --replicas=3 deployment/mysql  # If the deployment named mysql's current size is 2, scale mysql to 3

kubectl scale --replicas=5 rc/foo rc/bar rc/baz                   # Scale multiple replication controllers

删除资源 Deleting resources

kubectl delete -f ./pod.json                                      # Delete a pod using the type and name specified in pod.json

kubectl delete pod unwanted --now                                 # Delete a pod with no grace period

kubectl delete pod,service baz foo                                # Delete pods and services with same names "baz" and "foo"

kubectl delete pods,services -l name=myLabel                      # Delete pods and services with label name=myLabel

kubectl -n my-ns delete pod,svc --all                             # Delete all pods and services in namespace my-ns,

# Delete all pods matching the awk pattern1 or pattern2

kubectl get pods  -n mynamespace --no-headers=true | awk '/pattern1|pattern2/{print $1}' | xargs  kubectl delete -n mynamespace pod

和运行中的Pods交互 Interacting with running Pods

kubectl logs my-pod                                 # dump pod logs (stdout)
kubectl logs -l name=myLabel                        # dump pod logs, with label name=myLabel (stdout)
kubectl logs my-pod --previous                      # dump pod logs (stdout) for a previous instantiation of a container
kubectl logs my-pod -c my-container                 # dump pod container logs (stdout, multi-container case)
kubectl logs -l name=myLabel -c my-container        # dump pod logs, with label name=myLabel (stdout)
kubectl logs my-pod -c my-container --previous      # dump pod container logs (stdout, multi-container case) for a previous instantiation of a container
kubectl logs -f my-pod                              # stream pod logs (stdout)
kubectl logs -f my-pod -c my-container              # stream pod container logs (stdout, multi-container case)
kubectl logs -f -l name=myLabel --all-containers    # stream all pods logs with label name=myLabel (stdout)
kubectl run -i --tty busybox --image=busybox -- sh  # Run pod as interactive shell
kubectl run nginx --image=nginx -n mynamespace      # Start a single instance of nginx pod in the namespace of mynamespace
kubectl run nginx --image=nginx                     # Run pod nginx and write its spec into a file called pod.yaml
--dry-run=client -o yaml > pod.yaml

kubectl attach my-pod -i                            # Attach to Running Container
kubectl port-forward my-pod 5000:6000               # Listen on port 5000 on the local machine and forward to port 6000 on my-pod
kubectl exec my-pod -- ls /                         # Run command in existing pod (1 container case)
kubectl exec --stdin --tty my-pod -- /bin/sh        # Interactive shell access to a running pod (1 container case) 
kubectl exec my-pod -c my-container -- ls /         # Run command in existing pod (multi-container case)
kubectl top pod POD_NAME --containers               # Show metrics for a given pod and its containers
kubectl top pod POD_NAME --sort-by=cpu              # Show metrics for a given pod and sort it by 'cpu' or 'memory'

从容器中copy文件和目录 Copy files and directories to and from containers

kubectl cp /tmp/foo_dir my-pod:/tmp/bar_dir            # Copy /tmp/foo_dir local directory to /tmp/bar_dir in a remote pod in the current namespace

kubectl cp /tmp/foo my-pod:/tmp/bar -c my-container    # Copy /tmp/foo local file to /tmp/bar in a remote pod in a specific container

kubectl cp /tmp/foo my-namespace/my-pod:/tmp/bar       # Copy /tmp/foo local file to /tmp/bar in a remote pod in namespace my-namespace

kubectl cp my-namespace/my-pod:/tmp/foo /tmp/bar       # Copy /tmp/foo from a remote pod to /tmp/bar locally

Note: kubectl cp requires that the 'tar' binary is present in your container image. If 'tar' is not present,kubectl cp will fail. For advanced use cases, such as symlinks, wildcard expansion or file mode preservation consider using kubectl exec.

tar cf - /tmp/foo | kubectl exec -i -n my-namespace my-pod -- tar xf - -C /tmp/bar           # Copy /tmp/foo local file to /tmp/bar in a remote pod in namespace my-namespace

kubectl exec -n my-namespace my-pod -- tar cf - /tmp/foo | tar xf - -C /tmp/bar    # Copy /tmp/foo from a remote pod to /tmp/bar locally

和Deployments、Service交互 ： Interacting with Deployments and Services

kubectl logs deploy/my-deployment                         # dump Pod logs for a Deployment (single-container case)

kubectl logs deploy/my-deployment -c my-container         # dump Pod logs for a Deployment (multi-container case)



kubectl port-forward svc/my-service 5000                  # listen on local port 5000 and forward to port 5000 on Service backend

kubectl port-forward svc/my-service 5000:my-service-port  # listen on local port 5000 and forward to Service target port with name <my-service-port>



kubectl port-forward deploy/my-deployment 5000:6000       # listen on local port 5000 and forward to port 6000 on a Pod created by <my-deployment>

kubectl exec deploy/my-deployment -- ls                   # run command in first Pod and first container in Deployment (single- or multi-container cases)

和Nodes、集群交互：Interacting with Nodes and cluster

kubectl cordon my-node                                                # Mark my-node as unschedulable

kubectl drain my-node                                                 # Drain my-node in preparation for maintenance

kubectl uncordon my-node                                              # Mark my-node as schedulable

kubectl top node my-node                                              # Show metrics for a given node

kubectl cluster-info                                                  # Display addresses of the master and services

kubectl cluster-info dump                                             # Dump current cluster state to stdout

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



# If a taint with that key and effect already exists, its value is replaced as specified.

kubectl taint nodes foo dedicated=special-user:NoSchedule

资源类型 Resource types

列出所有支持的资源类型的短名称，API组，Namespace，以及类型。

kubectl api-resources

其他所有的API资源暴露接口

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

kubectl api-resources --namespaced=false     # All non-namespaced resources

kubectl api-resources -o name                # All resources with simple output (only the resource name)

kubectl api-resources -o wide                # All resources with expanded (aka "wide") output

kubectl api-resources --verbs=list,get       # All resources that support the "list" and "get" request verbs

kubectl api-resources --api-group=extensions # All resources in the "extensions" API group

格式化输出：Formatting output

用 -o (或者 --output) 参数格式化输出.

Output format	Description
-o=custom-columns=<spec>	Print a table using a comma separated list of custom columns
-o=custom-columns-file=<filename>	Print a table using the custom columns template in the <filename> file
-o=json	Output a JSON formatted API object
-o=jsonpath=<template>	Print the fields defined in a jsonpath expression
-o=jsonpath-file=<filename>	Print the fields defined by the jsonpath expression in the <filename> file
-o=name	Print only the resource name and nothing else
-o=wide	Output in the plain-text format with any additional information, and for pods, the node name is included
-o=yaml	Output a YAML formatted API object

例如：

Examples using -o=custom-columns:

# All images running in a cluster

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



# All images running in namespace: default, grouped by Pod

kubectl get pods --namespace default --output=custom-columns="NAME:.metadata.name,IMAGE:.spec.containers[*].image"



 # All images excluding "k8s.gcr.io/coredns:1.6.2"

kubectl get pods -A -o=custom-columns='DATA:spec.containers[?(@.image!="k8s.gcr.io/coredns:1.6.2")].image'



# All fields under metadata regardless of name

kubectl get pods -A -o=custom-columns='DATA:metadata.*'

Kubectl 详细输出模式和Debug模式 （verbosity and debugging）

Kubectl 输出详细程度由 -v 或者 --v 加一个数字控制的日志级别控制。 

Verbosity	Description
Verbosity	Description
--v=0	Generally useful for this to always be visible to a cluster operator.
--v=1	A reasonable default log level if you don't want verbosity.
--v=2	Useful steady state information about the service and important log messages that may correlate to significant changes in the system. This is the recommended default log level for most systems.
--v=3	Extended information about changes.
--v=4	Debug level verbosity.
--v=5	Trace level verbosity.
--v=6	Display requested resources.
--v=7	Display HTTP request headers.
--v=8	Display HTTP request contents.
--v=9	Display HTTP request contents without truncation of contents.