kubectl技巧之查看资源列表,资源版本和资源schema配置
在kubernetes里 pod,service,rs,rc,deploy,resource 等对象都需要使用yaml文件来创建,很多时候我们都是参照照官方示例或者一些第三方示例来编写yaml文件以创建对象.虽然这些示例很有典型性和代表性,能够满足我们大部分时候的需求,然而这往往还是不够的,根据项目不同,实际配置可能远比官方提供的demo配置复杂的多,这就要求我们除了掌握常用的配置外,还需要对其它配置有所了解.如果有一个文档能够速查某一对象的所有配置,不但方便我们学习不同的配置,也可以做为一个小手册以便我们记不起来某些配置时可以速查.
下面我们介绍一些小技巧来快速查看kubernetes api
查看所有api资源
可以通过命令kubectl api-resources来查看所有api资源
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[centos@k8s-master ~]$ kubectl api-resources
NAME SHORTNAMES APIGROUP NAMESPACED KIND
bindings true Binding
componentstatuses cs false ComponentStatus
configmaps cm true ConfigMap
endpoints ep true Endpoints
events ev true Event
limitranges limits true LimitRange
namespaces ns false Namespace
nodes no false Node
persistentvolumeclaims pvc true PersistentVolumeClaim
persistentvolumes pv false PersistentVolume
pods po true Pod
podtemplates true PodTemplate
replicationcontrollers rc true ReplicationController
resourcequotas quota true ResourceQuota
secrets true Secret
serviceaccounts sa true ServiceAccount
services svc true Service
mutatingwebhookconfigurations admissionregistration.k8s.io false MutatingWebhookConfiguration
validatingwebhookconfigurations admissionregistration.k8s.io false ValidatingWebhookConfiguration
customresourcedefinitions crd,crds apiextensions.k8s.io false CustomResourceDefinition
apiservices apiregistration.k8s.io false APIService
controllerrevisions apps true ControllerRevision
daemonsets ds apps true DaemonSet
deployments deploy apps true Deployment
replicasets rs apps true ReplicaSet
statefulsets sts apps true StatefulSet
tokenreviews authentication.k8s.io false TokenReview
localsubjectaccessreviews authorization.k8s.io true LocalSubjectAccessReview
selfsubjectaccessreviews authorization.k8s.io false SelfSubjectAccessReview
selfsubjectrulesreviews authorization.k8s.io false SelfSubjectRulesReview
subjectaccessreviews authorization.k8s.io false SubjectAccessReview
horizontalpodautoscalers hpa autoscaling true HorizontalPodAutoscaler
cronjobs cj batch true CronJob
jobs batch true Job
certificatesigningrequests csr certificates.k8s.io false CertificateSigningRequest
leases coordination.k8s.io true Lease
events ev events.k8s.io true Event
daemonsets ds extensions true DaemonSet
deployments deploy extensions true Deployment
ingresses ing extensions true Ingress
networkpolicies netpol extensions true NetworkPolicy
podsecuritypolicies psp extensions false PodSecurityPolicy
replicasets rs extensions true ReplicaSet
networkpolicies netpol networking.k8s.io true NetworkPolicy
poddisruptionbudgets pdb policy true PodDisruptionBudget
podsecuritypolicies psp policy false PodSecurityPolicy
clusterrolebindings rbac.authorization.k8s.io false ClusterRoleBinding
clusterroles rbac.authorization.k8s.io false ClusterRole
rolebindings rbac.authorization.k8s.io true RoleBinding
roles rbac.authorization.k8s.io true Role
priorityclasses pc scheduling.k8s.io false PriorityClass
storageclasses sc storage.k8s.io false StorageClass
volumeattachments storage.k8s.io false VolumeAttachment
除了可以看到资源的对象名称外,还可以看到对象的别名,这时候我们再看到别人的命令如kubectl get no这样费解的命令时就可以知道它实际上代表的是kubectl get nodes命令
查看api的版本,很多yaml配置里都需要指定配置的资源版本,我们经常看到v1,beta1,beta2这样的配置,到底某个资源的最新版本是什么呢?
其实,可以通过kubectl api-versions来查看api的版本
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[centos@k8s-master ~]$ kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
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/v1beta1
coordination.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
networking.k8s.io/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1
以上只是整体概况,很多时候我们还想要看到某个api下面都有哪些配置,某一荐配置的含义等,下面罗列一些常用的api范例和一些查看api的技巧
常见范例
通过kubectl explain查看api字段
通过kubectl explain <资源名对象名>查看资源对象拥有的字段
前面说过,可以通过kubectl api-resources来查看资源名称,如果想要查看某个资源的字段,可以通过kubectl explain <资源名对象名>来查点它都有哪些字段
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[centos@k8s-master ~]$ kubectl explain pod
KIND: Pod
VERSION: v1
DESCRIPTION:
Pod is a collection of containers that can run on a host. This resource is
created by clients and scheduled onto hosts.
FIELDS:
apiVersion <string>
APIVersion defines the versioned schema of this representation of an
object. Servers should convert recognized schemas to the latest internal
value, and may reject unrecognized values. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#resources
kind <string>
Kind is a string value representing the REST resource this object
represents. Servers may infer this from the endpoint the client submits
requests to. Cannot be updated. In CamelCase. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds
metadata <Object>
Standard object's metadata. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata
spec <Object>
Specification of the desired behavior of the pod. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
status <Object>
Most recently observed status of the pod. This data may not be up to date.
Populated by the system. Read-only. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
[centos@k8s-master ~]$
以上Description是对资源对象的简要描述,Fields则是对所有字段的描述
列出所有api字段
通过以上我们能感觉到,以上好像并没有罗列出所有的api字段,实际上以上列出的仅是一级字段,一级字段可能还包含二级的,三级的字段,想要罗列出所有的字段,可以加上
--recursive来列出所有可能的字段
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[centos@k8s-master ~]$ kubectl explain svc --recursive
KIND: Service
VERSION: v1
DESCRIPTION:
Service is a named abstraction of software service (for example, mysql)
consisting of local port (for example 3306) that the proxy listens on, and
the selector that determines which pods will answer requests sent through
the proxy.
FIELDS:
apiVersion <string>
kind <string>
metadata <Object>
annotations <map[string]string>
clusterName <string>
creationTimestamp <string>
deletionGracePeriodSeconds <integer>
deletionTimestamp <string>
finalizers <[]string>
generateName <string>
generation <integer>
initializers <Object>
pending <[]Object>
name <string>
result <Object>
apiVersion <string>
code <integer>
details <Object>
causes <[]Object>
field <string>
message <string>
reason <string>
group <string>
kind <string>
name <string>
retryAfterSeconds <integer>
uid <string>
kind <string>
message <string>
metadata <Object>
continue <string>
resourceVersion <string>
selfLink <string>
reason <string>
status <string>
labels <map[string]string>
name <string>
namespace <string>
ownerReferences <[]Object>
apiVersion <string>
blockOwnerDeletion <boolean>
controller <boolean>
kind <string>
name <string>
uid <string>
resourceVersion <string>
selfLink <string>
uid <string>
spec <Object>
clusterIP <string>
externalIPs <[]string>
externalName <string>
externalTrafficPolicy <string>
healthCheckNodePort <integer>
loadBalancerIP <string>
loadBalancerSourceRanges <[]string>
ports <[]Object>
name <string>
nodePort <integer>
port <integer>
protocol <string>
targetPort <string>
publishNotReadyAddresses <boolean>
selector <map[string]string>
sessionAffinity <string>
sessionAffinityConfig <Object>
clientIP <Object>
timeoutSeconds <integer>
type <string>
status <Object>
loadBalancer <Object>
ingress <[]Object>
hostname <string>
ip <string>
[centos@k8s-master ~]$
以上输出的内容是经过格式化了的,我们可以根据缩进很容易看到某一个字段从属于关系
查看具体字段
通过上面kubectl explain service --recursive可以看到所有的api名称,但是以上仅仅是罗列了所有的api名称,如果想要知道某一个api名称的详细信息,则可以通过kubectl explain <资源对象名称.api名称>的方式来查看,比如以下示例可以查看到service下的spec下的ports字段的信息
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[centos@k8s-master ~]$ kubectl explain svc.spec.ports
KIND: Service
VERSION: v1
RESOURCE: ports <[]Object>
DESCRIPTION:
The list of ports that are exposed by this service. More info:
https://kubernetes.io/docs/concepts/services-networking/service/#virtual-ips-and-service-proxies
ServicePort contains information on service's port.
FIELDS:
name <string>
The name of this port within the service. This must be a DNS_LABEL. All
ports within a ServiceSpec must have unique names. This maps to the 'Name'
field in EndpointPort objects. Optional if only one ServicePort is defined
on this service.
nodePort <integer>
The port on each node on which this service is exposed when type=NodePort
or LoadBalancer. Usually assigned by the system. If specified, it will be
allocated to the service if unused or else creation of the service will
fail. Default is to auto-allocate a port if the ServiceType of this Service
requires one. More info:
https://kubernetes.io/docs/concepts/services-networking/service/#type-nodeport
port <integer> -required-
The port that will be exposed by this service.
protocol <string>
The IP protocol for this port. Supports "TCP", "UDP", and "SCTP". Default
is TCP.
targetPort <string>
Number or name of the port to access on the pods targeted by the service.
Number must be in the range 1 to 65535. Name must be an IANA_SVC_NAME. If
this is a string, it will be looked up as a named port in the target Pod's
container ports. If this is not specified, the value of the 'port' field is
used (an identity map). This field is ignored for services with
clusterIP=None, and should be omitted or set equal to the 'port' field.
More info:
https://kubernetes.io/docs/concepts/services-networking/service/#defining-a-service
