版本清单
k api-versions，通过此命令可查询出现有的k8s集群所支持的kind版本。上面那个cronjob文件为例，可以知道，我这个集群，资源清单文件首行可以写成：apiVersion: batch/v1beta1 也可以写成apiVersion: batch/v1 这样的形式，在这个集群内都是OK的。
[root@master ~]# k api-versions admissionregistration.k8s.io/v1 admissionregistration.k8s.io/v1beta1 apiextensions.k8s.io/v1 apiextensions.k8s.io/v1beta1 apiregistration.k8s.io/v1 apiregistration.k8s.io/v1beta1 apps/v1 authentication.k8s.io/v1 authentication.k8s.io/v1beta1 authorization.k8s.io/v1 authorization.k8s.io/v1beta1 autoscaling/v1 autoscaling/v2beta1 autoscaling/v2beta2 batch/v1 batch/v1beta1 certificates.k8s.io/v1 certificates.k8s.io/v1beta1 coordination.k8s.io/v1 coordination.k8s.io/v1beta1 discovery.k8s.io/v1beta1 events.k8s.io/v1 events.k8s.io/v1beta1 extensions/v1beta1 networking.k8s.io/v1 networking.k8s.io/v1beta1 node.k8s.io/v1beta1 policy/v1beta1 rbac.authorization.k8s.io/v1 rbac.authorization.k8s.io/v1beta1 scheduling.k8s.io/v1 scheduling.k8s.io/v1beta1 storage.k8s.io/v1 storage.k8s.io/v1beta1 v1
- Basic Commands (Intermediate)里的get参数
kubectl命令里的get参数是使用频率最高的，没有之一，kubectl get --help 是该参数的详细介绍：
[root@master ~]# k get --help Display one or many resources Prints a table of the most important information about the specified resources. You can filter the list using a label selector and the --selector flag. If the desired resource type is namespaced you will only see results in your current namespace unless you pass --all-namespaces. Uninitialized objects are not shown unless --include-uninitialized is passed. By specifying the output as 'template' and providing a Go template as the value of the --template flag, you can filter the attributes of the fetched resources. Use "kubectl api-resources" for a complete list of supported resources. Examples: # List all pods in ps output format. kubectl get pods # List all pods in ps output format with more information (such as node name). kubectl get pods -o wide # List a single replication controller with specified NAME in ps output format. kubectl get replicationcontroller web # List deployments in JSON output format, in the "v1" version of the "apps" API group: kubectl get deployments.v1.apps -o json # List a single pod in JSON output format. kubectl get -o json pod web-pod-13je7 # List a pod identified by type and name specified in "pod.yaml" in JSON output format. kubectl get -f pod.yaml -o json # List resources from a directory with kustomization.yaml - e.g. dir/kustomization.yaml. kubectl get -k dir/ # Return only the phase value of the specified pod. kubectl get -o template pod/web-pod-13je7 --template={{.status.phase}} # List resource information in custom columns. kubectl get pod test-pod -o custom-columns=CONTAINER:.spec.containers[0].name,IMAGE:.spec.containers[0].image # List all replication controllers and services together in ps output format. kubectl get rc,services # List one or more resources by their type and names. kubectl get rc/web service/frontend pods/web-pod-13je7 Options: -A, --all-namespaces=false: If present, list the requested object(s) across all namespaces. Namespace in current context is ignored even if specified with --namespace. --allow-missing-template-keys=true: If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. --chunk-size=500: Return large lists in chunks rather than all at once. Pass 0 to disable. This flag is beta and may change in the future. --field-selector='': Selector (field query) to filter on, supports '=', '==', and '!='.(e.g. --field-selector key1=value1,key2=value2). The server only supports a limited number of field queries per type. -f, --filename=[]: Filename, directory, or URL to files identifying the resource to get from a server. --ignore-not-found=false: If the requested object does not exist the command will return exit code 0. -k, --kustomize='': Process the kustomization directory. This flag can't be used together with -f or -R. -L, --label-columns=[]: Accepts a comma separated list of labels that are going to be presented as columns. Names are case-sensitive. You can also use multiple flag options like -L label1 -L label2... --no-headers=false: When using the default or custom-column output format, don't print headers (default print headers). -o, --output='': Output format. One of: json|yaml|wide|name|custom-columns=...|custom-columns-file=...|go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=... See custom columns [http://kubernetes.io/docs/user-guide/kubectl-overview/#custom-columns], golang template [http://golang.org/pkg/text/template/#pkg-overview] and jsonpath template [http://kubernetes.io/docs/user-guide/jsonpath]. --output-watch-events=false: Output watch event objects when --watch or --watch-only is used. Existing objects are output as initial ADDED events. --raw='': Raw URI to request from the server. Uses the transport specified by the kubeconfig file. -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage related manifests organized within the same directory. -l, --selector='': Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2) --server-print=true: If true, have the server return the appropriate table output. Supports extension APIs and CRDs. --show-kind=false: If present, list the resource type for the requested object(s). --show-labels=false: When printing, show all labels as the last column (default hide labels column) --sort-by='': If non-empty, sort list types using this field specification. The field specification is expressed as a JSONPath expression (e.g. '{.metadata.name}'). The field in the API resource specified by this JSONPath expression must be an integer or a string. --template='': Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview]. -w, --watch=false: After listing/getting the requested object, watch for changes. Uninitialized objects are excluded if no object name is provided. --watch-only=false: Watch for changes to the requested object(s), without listing/getting first. Usage: kubectl get [(-o|--output=)json|yaml|wide|custom-columns=...|custom-columns-file=...|go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=...] (TYPE[.VERSION][.GROUP] [NAME | -l label] | TYPE[.VERSION][.GROUP]/NAME ...) [flags] [options] Use "kubectl options" for a list of global command-line options (applies to all commands).
该帮助给出了一些例子，总的来说，k get resource 名称即可，例如：
副本控制器 replicationcontrollers
[root@master ~]# k get rs -A NAMESPACE NAME DESIRED CURRENT READY AGE database mysql2-5db57c8bc8 1 1 1 4d default nfs-client-provisioner-556768d99f 0 0 0 4d1h default nfs-client-provisioner-5bd5bb49f 0 0 0 4d default nfs-client-provisioner-5c786944fc 0 0 0 4d1h default nfs-client-provisioner-6fc484bd4f 1 1 1 3d5h default nfs-client-provisioner-75ffb44498 0 0 0 4d default nfs-client-provisioner-7d8bb64cc 0 0 0 3d23h default nfs-client-provisioner-d7d7f8859 0 0 0 3d23h default nginx-7b54d48599 1 1 1 5h48m kube-system coredns-6c76c8bb89 2 2 2 27d
例如查询集群内所有角色：
[root@master ~]# k get clusterroles -A NAME CREATED AT admin 2022-06-13T02:56:43Z cluster-admin 2022-06-13T02:56:43Z edit 2022-06-13T02:56:43Z flannel 2022-07-06T08:07:44Z kubeadm:get-nodes 2022-06-13T02:56:45Z nfs-provisioner-runner 2022-07-06T08:09:42Z system:aggregate-to-admin 2022-06-13T02:56:43Z system:aggregate-to-edit 2022-06-13T02:56:43Z system:aggregate-to-view 2022-06-13T02:56:43Z system:auth-delegator 2022-06-13T02:56:43Z system:basic-user 2022-06-13T02:56:43Z system:certificates.k8s.io:certificatesigningrequests:nodeclient 2022-06-13T02:56:43Z system:certificates.k8s.io:certificatesigningrequests:selfnodeclient 2022-06-13T02:56:43Z system:certificates.k8s.io:kube-apiserver-client-approver 2022-06-13T02:56:43Z system:certificates.k8s.io:kube-apiserver-client-kubelet-approver 2022-06-13T02:56:43Z system:certificates.k8s.io:kubelet-serving-approver 2022-06-13T02:56:43Z system:certificates.k8s.io:legacy-unknown-approver 2022-06-13T02:56:43Z system:controller:attachdetach-controller 2022-06-13T02:56:43Z system:controller:certificate-controller 2022-06-13T02:56:44Z system:controller:clusterrole-aggregation-controller 2022-06-13T02:56:43Z system:controller:cronjob-controller 2022-06-13T02:56:43Z system:controller:daemon-set-controller 2022-06-13T02:56:44Z system:controller:deployment-controller 2022-06-13T02:56:44Z system:controller:disruption-controller 2022-06-13T02:56:44Z system:controller:endpoint-controller 2022-06-13T02:56:44Z system:controller:endpointslice-controller 2022-06-13T02:56:44Z system:controller:endpointslicemirroring-controller 2022-06-13T02:56:44Z system:controller:expand-controller 2022-06-13T02:56:44Z system:controller:generic-garbage-collector 2022-06-13T02:56:44Z system:controller:horizontal-pod-autoscaler 2022-06-13T02:56:44Z system:controller:job-controller 2022-06-13T02:56:44Z system:controller:namespace-controller 2022-06-13T02:56:44Z system:controller:node-controller 2022-06-13T02:56:44Z system:controller:persistent-volume-binder 2022-06-13T02:56:44Z system:controller:pod-garbage-collector 2022-06-13T02:56:44Z system:controller:pv-protection-controller 2022-06-13T02:56:44Z system:controller:pvc-protection-controller 2022-06-13T02:56:44Z system:controller:replicaset-controller 2022-06-13T02:56:44Z system:controller:replication-controller 2022-06-13T02:56:44Z system:controller:resourcequota-controller 2022-06-13T02:56:44Z system:controller:route-controller 2022-06-13T02:56:44Z system:controller:service-account-controller 2022-06-13T02:56:44Z system:controller:service-controller 2022-06-13T02:56:44Z system:controller:statefulset-controller 2022-06-13T02:56:44Z system:controller:ttl-controller 2022-06-13T02:56:44Z system:coredns 2022-06-13T02:56:45Z system:discovery 2022-06-13T02:56:43Z system:heapster 2022-06-13T02:56:43Z system:kube-aggregator 2022-06-13T02:56:43Z system:kube-controller-manager 2022-06-13T02:56:43Z system:kube-dns 2022-06-13T02:56:43Z system:kube-scheduler 2022-06-13T02:56:43Z system:kubelet-api-admin 2022-06-13T02:56:43Z system:node 2022-06-13T02:56:43Z system:node-bootstrapper 2022-06-13T02:56:43Z system:node-problem-detector 2022-06-13T02:56:43Z system:node-proxier 2022-06-13T02:56:43Z system:persistent-volume-provisioner 2022-06-13T02:56:43Z system:public-info-viewer 2022-06-13T02:56:43Z system:volume-scheduler 2022-06-13T02:56:43Z view 2022-06-13T02:56:43Z
查询角色绑定情况：
[root@master ~]# k get rolebindings -A NAMESPACE NAME ROLE AGE kube-public kubeadm:bootstrap-signer-clusterinfo Role/kubeadm:bootstrap-signer-clusterinfo 27d kube-public system:controller:bootstrap-signer Role/system:controller:bootstrap-signer 27d kube-system kube-proxy Role/kube-proxy 27d kube-system kubeadm:kubelet-config-1.19 Role/kubeadm:kubelet-config-1.19 27d kube-system kubeadm:nodes-kubeadm-config Role/kubeadm:nodes-kubeadm-config 27d kube-system system::extension-apiserver-authentication-reader Role/extension-apiserver-authentication-reader 27d kube-system system::leader-locking-kube-controller-manager Role/system::leader-locking-kube-controller-manager 27d kube-system system::leader-locking-kube-scheduler Role/system::leader-locking-kube-scheduler 27d kube-system system:controller:bootstrap-signer Role/system:controller:bootstrap-signer 27d kube-system system:controller:cloud-provider Role/system:controller:cloud-provider 27d kube-system system:controller:token-cleaner Role/system:controller:token-cleaner 27d
这里注意一点，查询所有 后面加个 -A 或者--all 都可以的哦：
[root@master ~]# k get rolebindings -A NAMESPACE NAME ROLE AGE kube-public kubeadm:bootstrap-signer-clusterinfo Role/kubeadm:bootstrap-signer-clusterinfo 27d kube-public system:controller:bootstrap-signer Role/system:controller:bootstrap-signer 27d kube-system kube-proxy Role/kube-proxy 27d kube-system kubeadm:kubelet-config-1.19 Role/kubeadm:kubelet-config-1.19 27d kube-system kubeadm:nodes-kubeadm-config Role/kubeadm:nodes-kubeadm-config 27d kube-system system::extension-apiserver-authentication-reader Role/extension-apiserver-authentication-reader 27d kube-system system::leader-locking-kube-controller-manager Role/system::leader-locking-kube-controller-manager 27d kube-system system::leader-locking-kube-scheduler Role/system::leader-locking-kube-scheduler 27d kube-system system:controller:bootstrap-signer Role/system:controller:bootstrap-signer 27d kube-system system:controller:cloud-provider Role/system:controller:cloud-provider 27d kube-system system:controller:token-cleaner Role/system:controller:token-cleaner 27d
官方的帮助文档其实已经非常详细了，在此我就抛砖引玉一下，只需要记住，k get resource名称 -A ，如果该资源有，那么就可以查询到，如果没有，它也会提示的哦，在比如，集群报错信息：
[root@master ~]# k get events -A NAMESPACE LAST SEEN TYPE REASON OBJECT MESSAGE default 8s Normal ExternalProvisioning persistentvolumeclaim/test-claim waiting for a volume to be created, either by external provisioner "fuseim.pri/ifs" or manually created by system administrator default 11m Warning FailedScheduling pod/test-pod 0/3 nodes are available: 3 pod has unbound immediate PersistentVolumeClaims.
根据以上提示，在查询pvc，可以看到现在有pvc状态是不对的：
[root@master ~]# k get pvc -A NAMESPACE NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE database nfs-pvc-test Bound nfs-pv-test1 1536Mi RWO nfs 4d default test-claim Pending managed-nfs-storage 3d5h
Troubleshooting and Debugging Commands里的describe和logs参数
describe和logs是在集群的使用过程中，各种各样的资源有可能会出现问题，此时，debug追踪查看问题原因时使用，也是使用非常多的参数
例如，k describe --help的帮助：
[root@master ~]# k describe --help Show details of a specific resource or group of resources Print a detailed description of the selected resources, including related resources such as events or controllers. You may select a single object by name, all objects of that type, provide a name prefix, or label selector. For example: $ kubectl describe TYPE NAME_PREFIX will first check for an exact match on TYPE and NAME_PREFIX. If no such resource exists, it will output details for every resource that has a name prefixed with NAME_PREFIX. Use "kubectl api-resources" for a complete list of supported resources. Examples: # Describe a node kubectl describe nodes kubernetes-node-emt8.c.myproject.internal # Describe a pod kubectl describe pods/nginx # Describe a pod identified by type and name in "pod.json" kubectl describe -f pod.json # Describe all pods kubectl describe pods # Describe pods by label name=myLabel kubectl describe po -l name=myLabel # Describe all pods managed by the 'frontend' replication controller (rc-created pods # get the name of the rc as a prefix in the pod the name). kubectl describe pods frontend Options: -A, --all-namespaces=false: If present, list the requested object(s) across all namespaces. Namespace in current context is ignored even if specified with --namespace. -f, --filename=[]: Filename, directory, or URL to files containing the resource to describe -k, --kustomize='': Process the kustomization directory. This flag can't be used together with -f or -R. -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage related manifests organized within the same directory. -l, --selector='': Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2) --show-events=true: If true, display events related to the described object. Usage: kubectl describe (-f FILENAME | TYPE [NAME_PREFIX | -l label] | TYPE/NAME) [options] Use "kubectl options" for a list of global command-line options (applies to all commands).
同样的，该参数也有详细的说明并且有一些简单的示例，例如查询本集群的slave1节点的详细信息：
[root@master ~]# k describe nodes slave1 Name: slave1 Roles: <none> Labels: beta.kubernetes.io/arch=amd64 beta.kubernetes.io/os=linux kubernetes.io/arch=amd64 kubernetes.io/hostname=slave1 kubernetes.io/os=linux Annotations: flannel.alpha.coreos.com/backend-data: {"VtepMAC":"52:04:85:12:ca:e2"} flannel.alpha.coreos.com/backend-type: vxlan flannel.alpha.coreos.com/kube-subnet-manager: true flannel.alpha.coreos.com/public-ip: 192.168.217.17 kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock node.alpha.kubernetes.io/ttl: 0 volumes.kubernetes.io/controller-managed-attach-detach: true CreationTimestamp: Mon, 13 Jun 2022 10:57:25 +0800 Taints: <none> Unschedulable: false Lease: HolderIdentity: slave1 AcquireTime: <unset> RenewTime: Sun, 10 Jul 2022 17:42:22 +0800 Conditions: Type Status LastHeartbeatTime LastTransitionTime Reason Message ---- ------ ----------------- ------------------ ------ ------- NetworkUnavailable False Sun, 10 Jul 2022 15:52:41 +0800 Sun, 10 Jul 2022 15:52:41 +0800 FlannelIsUp Flannel is running on this node MemoryPressure False Sun, 10 Jul 2022 17:38:35 +0800 Mon, 13 Jun 2022 10:57:26 +0800 KubeletHasSufficientMemory kubelet has sufficient memory available DiskPressure False Sun, 10 Jul 2022 17:38:35 +0800 Mon, 13 Jun 2022 10:57:26 +0800 KubeletHasNoDiskPressure kubelet has no disk pressure PIDPressure False Sun, 10 Jul 2022 17:38:35 +0800 Mon, 13 Jun 2022 10:57:26 +0800 KubeletHasSufficientPID kubelet has sufficient PID available Ready True Sun, 10 Jul 2022 17:38:35 +0800 Mon, 13 Jun 2022 10:57:36 +0800 KubeletReady kubelet is posting ready status Addresses: InternalIP: 192.168.217.17 Hostname: slave1 Capacity: cpu: 8 ephemeral-storage: 10230Mi hugepages-2Mi: 0 memory: 4026340Ki pods: 110 Allocatable: cpu: 8 ephemeral-storage: 9654239217 hugepages-2Mi: 0 memory: 3923940Ki pods: 110 System Info: Machine ID: 9e1e6e06c15e4e43a32b308f9e7106fa System UUID: 2ed24d56-5e02-0ef6-f3fc-b3acc3e99e89 Boot ID: 6e80cbd7-8f7d-46cc-9458-cb040dbf3206 Kernel Version: 5.16.9-1.el7.elrepo.x86_64 OS Image: CentOS Linux 7 (Core) Operating System: linux Architecture: amd64 Container Runtime Version: docker://20.10.7 Kubelet Version: v1.19.4 Kube-Proxy Version: v1.19.4 PodCIDR: 10.244.1.0/24 PodCIDRs: 10.244.1.0/24 Non-terminated Pods: (5 in total) Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits AGE --------- ---- ------------ ---------- --------------- ------------- --- database mysql2-5db57c8bc8-7bwbg 0 (0%) 0 (0%) 0 (0%) 0 (0%) 4d default nginx-7b54d48599-x2zc5 0 (0%) 0 (0%) 0 (0%) 0 (0%) 6h9m kube-system coredns-6c76c8bb89-tfcrm 100m (1%) 0 (0%) 70Mi (1%) 170Mi (4%) 27d kube-system kube-flannel-ds-djwmq 100m (1%) 100m (1%) 50Mi (1%) 50Mi (1%) 4d1h kube-system kube-proxy-mtttm 0 (0%) 0 (0%) 0 (0%) 0 (0%) 27d Allocated resources: (Total limits may be over 100 percent, i.e., overcommitted.) Resource Requests Limits -------- -------- ------ cpu 200m (2%) 100m (1%) memory 120Mi (3%) 220Mi (5%) ephemeral-storage 0 (0%) 0 (0%) hugepages-2Mi 0 (0%) 0 (0%) Events: <none>
该节点的非常详细的信息都查询出来了，比如，运行了哪些pod，当然，我们也可以使用组合命令来查询slave1到底有运行哪些pod，但是，describe是把非常多的信息都给列出来了啊：
[root@master ~]# k get pods -A -o wide |grep slave1 database mysql2-5db57c8bc8-7bwbg 1/1 Running 4 4d 10.244.1.14 slave1 <none> <none> default nginx-7b54d48599-x2zc5 1/1 Running 1 6h12m 10.244.1.12 slave1 <none> <none> kube-system coredns-6c76c8bb89-tfcrm 1/1 Running 5 27d 10.244.1.13 slave1 <none> <none> kube-system kube-flannel-ds-djwmq 1/1 Running 4 4d1h 192.168.217.17 slave1 <none> <none> kube-system kube-proxy-mtttm 1/1 Running 5 27d 192.168.217.17 slave1 <none> <none>
两个命令可以互相印证的哦，k describe node slave1 里关于slave1里有哪些pods和 k get pods -A -o wide |grep slave1 结果是一致的哦。
还有一些别的参数，比如logs，apply等等参数，都可以通过--help查询出来具体的用法，在此就不献丑了。
总结：
kubectl 命令参数非常多，但常用的应该也就十来个吧，大体上是有这样一些常用参数：
describe，get，apply，taint，create，run，logs，delete，api-version,version,api-resources,rollout,scale,edit,expose,replace
如有遗漏，欢迎补充哦
