K8S（三）-资源清单
资源：
kubernetes把资源实例化之后称为对象，常见的资源有：
- workload: Pod,ReplicaSet,Deployment,StatefulSet DaemonSet,Job,Cronjob,...
- 服务发现及均衡： service，ingress
- 配置与存储：Volume(云端存储,分布式存储,nfs,glastfs), CSI容器存储接口,configmap(配置中心),secret(保存敏感信息)，DownwordAPI
- 集群级资源： Namespace, Node, Role, ClusterRole, RoleBanding, ClusterRoleBanding
- 元数据型资源： HPA, PodTemlate, limitRange
查看pod的资源清单：
# kubectl get pod myapp-5bc569c47d-5cvcx -o yaml
apiVersion: v1 kind: Pod metadata: creationTimestamp: "2019-10-09T03:11:08Z" generateName: myapp-5bc569c47d- labels: pod-template-hash: 5bc569c47d release: stable run: myapp name: myapp-5bc569c47d-5cvcx namespace: default ownerReferences: - apiVersion: apps/v1 blockOwnerDeletion: true controller: true kind: ReplicaSet name: myapp-5bc569c47d uid: 70044b8c-ea42-11e9-9460-fa163e359251 resourceVersion: "2283413" selfLink: /api/v1/namespaces/default/pods/myapp-5bc569c47d-5cvcx uid: 70151f83-ea42-11e9-9460-fa163e359251 spec: containers: - image: ikubernetes/myapp:v1 imagePullPolicy: IfNotPresent name: myapp resources: {} terminationMessagePath: /dev/termination-log terminationMessagePolicy: File volumeMounts: - mountPath: /var/run/secrets/kubernetes.io/serviceaccount name: default-token-bpr69 readOnly: true dnsPolicy: ClusterFirst enableServiceLinks: true nodeName: szgl-szgl-baol1-test03-8144.jpushoa.com priority: 0 restartPolicy: Always schedulerName: default-scheduler securityContext: {} serviceAccount: default serviceAccountName: default terminationGracePeriodSeconds: 30 tolerations: - effect: NoExecute key: node.kubernetes.io/not-ready operator: Exists tolerationSeconds: 300 - effect: NoExecute key: node.kubernetes.io/unreachable operator: Exists tolerationSeconds: 300 volumes: - name: default-token-bpr69 secret: defaultMode: 420 secretName: default-token-bpr69 status: conditions: - lastProbeTime: null lastTransitionTime: "2019-10-09T03:11:08Z" status: "True" type: Initialized - lastProbeTime: null lastTransitionTime: "2019-10-09T03:11:55Z" status: "True" type: Ready - lastProbeTime: null lastTransitionTime: "2019-10-09T03:11:55Z" status: "True" type: ContainersReady - lastProbeTime: null lastTransitionTime: "2019-10-09T03:11:08Z" status: "True" type: PodScheduled containerStatuses: - containerID: docker://67f6558d7f14f73a0bc67cf06084a6031896a230b8904b3738c1d48738cd4c2f image: ikubernetes/myapp:v1 imageID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513 lastState: {} name: myapp ready: true restartCount: 0 state: running: startedAt: "2019-10-09T03:11:54Z" hostIP: 172.17.8.144 phase: Running podIP: 10.244.1.8 qosClass: BestEffort startTime: "2019-10-09T03:11:08Z"
apiVersion: v1 # group/version，如果没有给定group名称那么默认为core,可以使用kubectl api-versions获取当前k8s版本上所有的apiVersion版本信息(每个版本可能不同) kind: Pod #资源类别，可以是Deployment、Service、Ingress等 metadata: #资源元数据 name namespace labels annotations spec: # 期望的状态，定义资源对象应该具有的特性，比如容器是几个，每个容器用什么镜像创建，容忍度，污点等，然后靠控制器来确保状态被满足 status：#显示当前状态。只读。本字段用户不能定义，是由kubenetes集群来维护
每个资源的引用PATH
/api/GROUP/VERSION/namespaces/NAMESPACE/TYPE/NAME
创建资源的方法：
- apiserver在定义资源时，仅接收JSON格式的资源定义。像使用run来创建deployment时，run命令会自动把内容转成json。
- 利用yaml格式提供配置清单，apiserver可自动将其转为json格式，而后再提交并执行。
查看资源的详细说明：
# kubectl explain ingress
# kubectl explain pod
# kubectl explain pod.metadata
KIND: Pod VERSION: v1 RESOURCE: metadata <Object> DESCRIPTION: Standard object's metadata. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata ObjectMeta is metadata that all persisted resources must have, which includes all objects users must create. FIELDS: annotations <map[string]string> Annotations is an unstructured key value map stored with a resource that may be set by external tools to store and retrieve arbitrary metadata. They are not queryable and should be preserved when modifying objects. More info: http://kubernetes.io/docs/user-guide/annotations clusterName <string> The name of the cluster which the object belongs to. This is used to distinguish resources with same name and namespace in different clusters. This field is not set anywhere right now and apiserver is going to ignore it if set in create or update request. creationTimestamp <string> CreationTimestamp is a timestamp representing the server time when this object was created. It is not guaranteed to be set in happens-before order across separate operations. Clients may not set this value. It is represented in RFC3339 form and is in UTC. Populated by the system. Read-only. Null for lists. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata deletionGracePeriodSeconds <integer> Number of seconds allowed for this object to gracefully terminate before it will be removed from the system. Only set when deletionTimestamp is also set. May only be shortened. Read-only. deletionTimestamp <string> DeletionTimestamp is RFC 3339 date and time at which this resource will be deleted. This field is set by the server when a graceful deletion is requested by the user, and is not directly settable by a client. The resource is expected to be deleted (no longer visible from resource lists, and not reachable by name) after the time in this field, once the finalizers list is empty. As long as the finalizers list contains items, deletion is blocked. Once the deletionTimestamp is set, this value may not be unset or be set further into the future, although it may be shortened or the resource may be deleted prior to this time. For example, a user may request that a pod is deleted in 30 seconds. The Kubelet will react by sending a graceful termination signal to the containers in the pod. After that 30 seconds, the Kubelet will send a hard termination signal (SIGKILL) to the container and after cleanup, remove the pod from the API. In the presence of network partitions, this object may still exist after this timestamp, until an administrator or automated process can determine the resource is fully terminated. If not set, graceful deletion of the object has not been requested. Populated by the system when a graceful deletion is requested. Read-only. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata finalizers <[]string> Must be empty before the object is deleted from the registry. Each entry is an identifier for the responsible component that will remove the entry from the list. If the deletionTimestamp of the object is non-nil, entries in this list can only be removed. generateName <string> GenerateName is an optional prefix, used by the server, to generate a unique name ONLY IF the Name field has not been provided. If this field is used, the name returned to the client will be different than the name passed. This value will also be combined with a unique suffix. The provided value has the same validation rules as the Name field, and may be truncated by the length of the suffix required to make the value unique on the server. If this field is specified and the generated name exists, the server will NOT return a 409 - instead, it will either return 201 Created or 500 with Reason ServerTimeout indicating a unique name could not be found in the time allotted, and the client should retry (optionally after the time indicated in the Retry-After header). Applied only if Name is not specified. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#idempotency generation <integer> A sequence number representing a specific generation of the desired state. Populated by the system. Read-only. initializers <Object> An initializer is a controller which enforces some system invariant at object creation time. This field is a list of initializers that have not yet acted on this object. If nil or empty, this object has been completely initialized. Otherwise, the object is considered uninitialized and is hidden (in list/watch and get calls) from clients that haven't explicitly asked to observe uninitialized objects. When an object is created, the system will populate this list with the current set of initializers. Only privileged users may set or modify this list. Once it is empty, it may not be modified further by any user. DEPRECATED - initializers are an alpha field and will be removed in v1.15. labels <map[string]string> Map of string keys and values that can be used to organize and categorize (scope and select) objects. May match selectors of replication controllers and services. More info: http://kubernetes.io/docs/user-guide/labels managedFields <[]Object> ManagedFields maps workflow-id and version to the set of fields that are managed by that workflow. This is mostly for internal housekeeping, and users typically shouldn't need to set or understand this field. A workflow can be the user's name, a controller's name, or the name of a specific apply path like "ci-cd". The set of fields is always in the version that the workflow used when modifying the object. This field is alpha and can be changed or removed without notice. name <string> Name must be unique within a namespace. Is required when creating resources, although some resources may allow a client to request the generation of an appropriate name automatically. Name is primarily intended for creation idempotence and configuration definition. Cannot be updated. More info: http://kubernetes.io/docs/user-guide/identifiers#names namespace <string> Namespace defines the space within each name must be unique. An empty namespace is equivalent to the "default" namespace, but "default" is the canonical representation. Not all objects are required to be scoped to a namespace - the value of this field for those objects will be empty. Must be a DNS_LABEL. Cannot be updated. More info: http://kubernetes.io/docs/user-guide/namespaces ownerReferences <[]Object> List of objects depended by this object. If ALL objects in the list have been deleted, this object will be garbage collected. If this object is managed by a controller, then an entry in this list will point to this controller, with the controller field set to true. There cannot be more than one managing controller. resourceVersion <string> An opaque value that represents the internal version of this object that can be used by clients to determine when objects have changed. May be used for optimistic concurrency, change detection, and the watch operation on a resource or set of resources. Clients must treat these values as opaque and passed unmodified back to the server. They may only be valid for a particular resource or set of resources. Populated by the system. Read-only. Value must be treated as opaque by clients and . More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#concurrency-control-and-consistency selfLink <string> SelfLink is a URL representing this object. Populated by the system. Read-only. uid <string> UID is the unique in time and space value for this object. It is typically generated by the server on successful creation of a resource and is not allowed to change on PUT operations. Populated by the system. Read-only. More info: http://kubernetes.io/docs/user-guide/identifiers#uids
字段的格式说明：
-required- 表示必选字段
<string> 字符串类型
<integer> 整型
<Object> 表示需要嵌套多层字段
<[]Object> 对象列表
<map[string]string> 映射，k:v格式
<boolean> 布尔类型
使用配置清单创建pod
# cat test-pod.yml
apiVersion: v1
kind: Pod
metadata:
name: test-pod
namespace: default
labels:
app: myapp
project: dev
spec:
containers: #一个pod中运行两个容器
- name: myapp
image: ikubernetes/myapp:v1
- name: busybox
image: busybox:latest
command:
- "/bin/sh"
- "-c"
- "sleep 3600"
创建：
# kubectl create -f test-pod.yaml
pod/test-pod created
查看：
# kubectl get pods -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES test-pod 2/2 Running 0 31s 10.244.1.39 node01 <none> <none>
# kubectl describe pods test-pod 可以看到起来了两个容器
访问pod
# curl 10.244.1.39
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
查看访问日志：
# kubectl logs test-pod -c myapp
10.244.0.0 - - [23/Oct/2019:01:47:18 +0000] "GET / HTTP/1.1" 200 65 "-" "curl/7.29.0" "-"
删除清单定义
# kubectl delete -f test-pod.yml
pod "test-pod" deleted
