玩转k8s：yaml介绍
一.Yaml文件详解
1.Yaml文件格式
（1）Kubernetes 支持 YAML 和 JSON 格式管理资源对象
（2）JSON 格式：主要用于 api 接口之间消息的传递
（3）YAML 格式：用于配置和管理，YAML 是一种简洁的非标记性语言，内容格式人性化，较易读
2.YAML 语法格式
（1）大小写敏感
（2）使用缩进表示层级关系
（3）不支持Tab键制表符缩进，只使用空格缩进
（4）缩进的空格数目不重要，只要相同层级的元素左侧对齐即可，通常开头缩进两个空格
（5）符号字符后缩进一个空格，如冒号，逗号，短横杆（-）等
（6）“---”表示YAML格式，一个文件的开始，用于分隔文件间
（7）“#”表示注释
二.Yaml文件编写及相关概念
1.查看 api 资源版本标签
kubectl api-versions[root@k8s-master-136 ~]# kubectl 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
crd.projectcalico.org/v1
discovery.k8s.io/v1
discovery.k8s.io/v1beta1
events.k8s.io/v1
events.k8s.io/v1beta1
extensions/v1beta1
flowcontrol.apiserver.k8s.io/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1
node.k8s.io/v1beta1
policy/v1
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
v12.yaml编写案例
#查看deployment的版本定义
kubectl explain deployment[root@k8s-master-136 ~]# kubectl explain deployment
KIND: Deployment
VERSION: apps/v1DESCRIPTION:Deployment enables declarative updates for Pods and ReplicaSets.FIELDS:apiVersion <string>APIVersion defines the versioned schema of this representation of anobject. Servers should convert recognized schemas to the latest internalvalue, and may reject unrecognized values. More info:https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resourceskind <string>Kind is a string value representing the REST resource this objectrepresents. Servers may infer this from the endpoint the client submitsrequests to. Cannot be updated. In CamelCase. More info:https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kindsmetadata <Object>Standard object metadata.spec <Object>Specification of the desired behavior of the Deployment.status <Object>Most recently observed status of the Deployment.#查看api的版本
kubectl explain deployment.apiVersion[root@k8s-master-136 ~]# kubectl explain deployment.apiVersion
KIND: Deployment
VERSION: apps/v1FIELD: apiVersion <string>DESCRIPTION:APIVersion defines the versioned schema of this representation of anobject. Servers should convert recognized schemas to the latest internalvalue, and may reject unrecognized values. More info:https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources#查看元数据信息
kubectl explain deployment.apiVersion#定义标签介绍
kubectl explain deployment.spec.selector[root@k8s-master-136 ~]# kubectl explain deployment.spec.selector
KIND: Deployment
VERSION: apps/v1RESOURCE: selector <Object>DESCRIPTION:Label selector for pods. Existing ReplicaSets whose pods are selected bythis will be the ones affected by this deployment. It must match the podtemplate's labels.A label selector is a label query over a set of resources. The result ofmatchLabels and matchExpressions are ANDed. An empty label selector matchesall objects. A null label selector matches no objects.FIELDS:matchExpressions <[]Object>matchExpressions is a list of label selector requirements. The requirementsare ANDed.matchLabels <map[string]string>matchLabels is a map of {key,value} pairs. A single {key,value} in thematchLabels map is equivalent to an element of matchExpressions, whose keyfield is "key", the operator is "In", and the values array contains only"value". The requirements are ANDed.#对matchLabels标签介绍
kubectl explain deployment.spec.selector.matchLabels[root@k8s-master-136 ~]# kubectl explain deployment.spec.selector.matchLabels
KIND: Deployment
VERSION: apps/v1FIELD: matchLabels <map[string]string>DESCRIPTION:matchLabels is a map of {key,value} pairs. A single {key,value} in thematchLabels map is equivalent to an element of matchExpressions, whose keyfield is "key", the operator is "In", and the values array contains only"value". The requirements are ANDed.Deployment类型编写nginx服务
创建pod
vim nginx-deployment.yamlapiVersion: apps/v1 #指定api版本标签
kind: Deployment #定义资源的类型/角色，deployment为副本控制器，此处资源类型可以是Deployment、Job、Ingress、Service等
metadata: #定义资源的元数据信息，比如资源的名称、namespace、标签等信息name: nginx-deployment #定义资源的名称，在同一个namespace空间中必须是唯一的namespace： default #默认就是default，可以不用写labels: #定义Deployment资源标签app: nginx
spec: #定义deployment资源需要的参数属性，诸如是否在容器失败时重新启动容器的属性replicas: 3 #定义副本数量selector: #定义标签选择器matchLabels: #定义匹配标签app: nginx #需与 .spec.template.metadata.labels 定义的标签保持一致template: #定义业务模板，如果有多个副本，所有副本的属性会按照模板的相关配置进行匹配metadata:labels: #定义Pod副本将使用的标签，需与 .spec.selector.matchLabels 定义的标签保持一致app: nginxspec:containers: #定义容器属性- name: nginx #定义一个容器名，一个 - name: 定义一个容器image: nginx:1.15.4 #定义容器使用的镜像以及版本ports:- containerPort: 80 #定义容器的对外的端口#创建资源对象
kubectl create -f nginx-deployment.yaml
或
kubectl apply -f nginx-deployment.yaml
#查看创建的资源对象，创建需等待running
kubectl get pod容器如果想对外提供访问，需创建service 发布
#创建service服务对外提供访问并测试
vim nginx-service.yamlapiVersion: v1
kind: Service
metadata:name: nginx-servicelabels:app: nginx
spec:selector:app: nginxtype: NodePort ports:- port: 80targetPort: 80 #创建资源对象
kubectl create -f nginx-service.yaml
或
kubectl apply -f nginx-service.yaml
#查看创建的service
kubectl get svck8s集群中的port介绍
详解k8s中的port：
●port
port 是 k8s 集群内部访问service的端口，即通过 clusterIP: port 可以从 Pod 所在的 Node 上访问到 service
●nodePort
nodePort 是外部访问 k8s 集群中 service 的端口，通过 nodeIP: nodePort 可以从外部访问到某个 service。
●targetPort
targetPort 是 Pod 的端口，从 port 或 nodePort 来的流量经过 kube-proxy 反向代理负载均衡转发到后端 Pod 的 targetPort 上，最后进入容器。
●containerPort
containerPort 是 Pod 内部容器的端口，targetPort 映射到 containerPort。