资源清单介绍
创建资源的方法
apiserver仅接收JSON格式的资源定义
yaml格式提供配置清单 apiserver可自动把yaml转换成json格式数据
资源清单五个一级字段
1.apiVersion group/version
使用kubectl api-versions来获取
2.kind 资源类别
3.metadata 元数据
name
namespace
labels
annotations
4.spec 期望的状态
5.satus 当前状态 由k8s维护数据 只能读不能修改 pod控制器的作用就是使各个pod的状态无限的向spec期望的状态靠近
资源清单格式示例
[root@k8s-master mainfests]# vi pod-demo.yml apiVersion: v1 kind: Pod metadata: name: pod-demo namespace: default labels: app: myapp tier: frontend spec: containers: - name: myapp image: ikubernetes/myapp:v1 - name: busybox image: busybox:latest command: - "/bin/sh" - "-c" - "sleep 5"
1.执行创建 kubectl create -f pod-demo.yml 2.执行删除 kubectl delete -f pod-demo.yml
3.查看pod中指定容器日志
[root@k8s-master mainfests]# kubectl logs pod-demo busybox /bin/sh: can't create /usr/share/nginx/html/index.html: nonexistent directory
[root@k8s-master mainfests]# kubectl get pods NAME READY STATUS RESTARTS AGE client 1/1 Running 0 1d myapp-74c94dcb8c-dp9t4 1/1 Running 0 45m myapp-74c94dcb8c-jplgj 1/1 Running 0 45m myapp-74c94dcb8c-mjjpw 1/1 Running 0 1d nginx-deploy-5b595999-d7rpg 1/1 Running 0 227d nginx-deploy-5b595999-xkzqz 1/1 Running 0 45m pod-demo 1/2 CrashLoopBackOff 2 3m [root@k8s-master mainfests]# kubectl describe pods pod-demo Name: pod-demo Namespace: default Priority: 0 PriorityClassName: <none> Node: node3/192.168.11.143 Start Time: Tue, 21 May 2019 18:15:34 +0800 Labels: app=myapp tier=frontend Annotations: <none> Status: Running IP: 10.244.2.14 Containers: myapp: Container ID: docker://ff766f6291cf5e6c3ee92113e8031c59ecffa7871eb9f765602235eda3cc0f30 Image: ikubernetes/myapp:v1 Image ID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513 Port: <none> Host Port: <none> State: Running Started: Tue, 21 May 2019 18:15:45 +0800 Ready: True Restart Count: 0 Environment: <none> Mounts: /var/run/secrets/kubernetes.io/serviceaccount from default-token-n87jl (ro) busybox: Container ID: docker://19d6b5bee5c1fc349a2751bcc560d049ff1972c821ac2d6fac3a09bf8121517d Image: busybox:latest Image ID: docker-pullable://busybox@sha256:4b6ad3a68d34da29bf7c8ccb5d355ba8b4babcad1f99798204e7abb43e54ee3d Port: <none> Host Port: <none> Command: /bin/sh -c echo $(date) >> /usr/share/nginx/html/index.html; sleep 5 State: Waiting Reason: ErrImagePull Last State: Terminated Reason: Completed Exit Code: 0 Started: Tue, 21 May 2019 18:16:23 +0800 Finished: Tue, 21 May 2019 18:16:29 +0800 Ready: False Restart Count: 0 Environment: <none> Mounts: /var/run/secrets/kubernetes.io/serviceaccount from default-token-n87jl (ro) Conditions: Type Status Initialized True Ready False ContainersReady False PodScheduled True Volumes: default-token-n87jl: Type: Secret (a volume populated by a Secret) SecretName: default-token-n87jl Optional: false QoS Class: BestEffort Node-Selectors: <none> Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s node.kubernetes.io/unreachable:NoExecute for 300s Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 1m default-scheduler Successfully assigned default/pod-demo to node3 Normal Pulled 1m kubelet, node3 Container image "ikubernetes/myapp:v1" already present on machine Normal Created 1m kubelet, node3 Created container Normal Started 1m kubelet, node3 Started container Normal Pulled 32s kubelet, node3 Successfully pulled image "busybox:latest" Normal Created 32s kubelet, node3 Created container Normal Started 31s kubelet, node3 Started container Warning Failed 12s kubelet, node3 Failed to pull image "busybox:latest": rpc error: code = Unknown desc = Error response from daemon: Get https://registry-1.docker.io/v2/library/busybox/manifests/latest: net/http: TLS handshake timeout Warning Failed 12s kubelet, node3 Error: ErrImagePull Normal Pulling 1s (x3 over 1m) kubelet, node3 pulling image "busybox:latest" [root@k8s-master mainfests]# kubectl exec -it pod-demo myapp Defaulting container name to myapp. Use 'kubectl describe pod/pod-demo -n default' to see all of the containers in this pod. rpc error: code = 2 desc = oci runtime error: exec failed: container_linux.go:247: starting container process caused "exec: "myapp": executable file not found in $PATH" command terminated with exit code 126
4.进入pod容器执行命令
[root@k8s-master mainfests]# kubectl exec -it pod-demo -c myapp -- /bin/sh / # cat /usr/share/nginx/html/index.html Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
5.查看清单文件语法帮助
[root@k8s-master ~]# kubectl explain pods.spec KIND: Pod VERSION: v1 RESOURCE: spec <Object> DESCRIPTION: Specification of the desired behavior of the pod. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status PodSpec is a description of a pod. FIELDS: activeDeadlineSeconds <integer> Optional duration in seconds the pod may be active on the node relative to StartTime before the system will actively try to mark it failed and kill associated containers. Value must be a positive integer. affinity <Object> If specified, the pod's scheduling constraints automountServiceAccountToken <boolean> AutomountServiceAccountToken indicates whether a service account token should be automatically mounted. containers <[]Object> -required- List of containers belonging to the pod. Containers cannot currently be added or removed. There must be at least one container in a Pod. Cannot be updated. dnsConfig <Object> Specifies the DNS parameters of a pod. Parameters specified here will be merged to the generated DNS configuration based on DNSPolicy. dnsPolicy <string> Set DNS policy for the pod. Defaults to "ClusterFirst". Valid values are 'ClusterFirstWithHostNet', 'ClusterFirst', 'Default' or 'None'. DNS parameters given in DNSConfig will be merged with the policy selected with DNSPolicy. To have DNS options set along with hostNetwork, you have to specify DNS policy explicitly to 'ClusterFirstWithHostNet'. hostAliases <[]Object> HostAliases is an optional list of hosts and IPs that will be injected into the pod's hosts file if specified. This is only valid for non-hostNetwork pods. hostIPC <boolean> Use the host's ipc namespace. Optional: Default to false. hostNetwork <boolean> Host networking requested for this pod. Use the host's network namespace. If this option is set, the ports that will be used must be specified. Default to false. hostPID <boolean> Use the host's pid namespace. Optional: Default to false. hostname <string> Specifies the hostname of the Pod If not specified, the pod's hostname will be set to a system-defined value. imagePullSecrets <[]Object> ImagePullSecrets is an optional list of references to secrets in the same namespace to use for pulling any of the images used by this PodSpec. If specified, these secrets will be passed to individual puller implementations for them to use. For example, in the case of docker, only DockerConfig type secrets are honored. More info: https://kubernetes.io/docs/concepts/containers/images#specifying-imagepullsecrets-on-a-pod initContainers <[]Object> List of initialization containers belonging to the pod. Init containers are executed in order prior to containers being started. If any init container fails, the pod is considered to have failed and is handled according to its restartPolicy. The name for an init container or normal container must be unique among all containers. Init containers may not have Lifecycle actions, Readiness probes, or Liveness probes. The resourceRequirements of an init container are taken into account during scheduling by finding the highest request/limit for each resource type, and then using the max of of that value or the sum of the normal containers. Limits are applied to init containers in a similar fashion. Init containers cannot currently be added or removed. Cannot be updated. More info: https://kubernetes.io/docs/concepts/workloads/pods/init-containers/ nodeName <string> NodeName is a request to schedule this pod onto a specific node. If it is non-empty, the scheduler simply schedules this pod onto that node, assuming that it fits resource requirements. nodeSelector <map[string]string> NodeSelector is a selector which must be true for the pod to fit on a node. Selector which must match a node's labels for the pod to be scheduled on that node. More info: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/ priority <integer> The priority value. Various system components use this field to find the priority of the pod. When Priority Admission Controller is enabled, it prevents users from setting this field. The admission controller populates this field from PriorityClassName. The higher the value, the higher the priority. priorityClassName <string> If specified, indicates the pod's priority. "system-node-critical" and "system-cluster-critical" are two special keywords which indicate the highest priorities with the former being the highest priority. Any other name must be defined by creating a PriorityClass object with that name. If not specified, the pod priority will be default or zero if there is no default. readinessGates <[]Object> If specified, all readiness gates will be evaluated for pod readiness. A pod is ready when all its containers are ready AND all conditions specified in the readiness gates have status equal to "True" More info: https://github.com/kubernetes/community/blob/master/keps/sig-network/0007-pod-ready%2B%2B.md restartPolicy <string> Restart policy for all containers within the pod. One of Always, OnFailure, Never. Default to Always. More info: https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#restart-policy schedulerName <string> If specified, the pod will be dispatched by specified scheduler. If not specified, the pod will be dispatched by default scheduler. securityContext <Object> SecurityContext holds pod-level security attributes and common container settings. Optional: Defaults to empty. See type description for default values of each field. serviceAccount <string> DeprecatedServiceAccount is a depreciated alias for ServiceAccountName. Deprecated: Use serviceAccountName instead. serviceAccountName <string> ServiceAccountName is the name of the ServiceAccount to use to run this pod. More info: https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/ shareProcessNamespace <boolean> Share a single process namespace between all of the containers in a pod. When this is set containers will be able to view and signal processes from other containers in the same pod, and the first process in each container will not be assigned PID 1. HostPID and ShareProcessNamespace cannot both be set. Optional: Default to false. This field is alpha-level and is honored only by servers that enable the PodShareProcessNamespace feature. subdomain <string> If specified, the fully qualified Pod hostname will be "<hostname>.<subdomain>.<pod namespace>.svc.<cluster domain>". If not specified, the pod will not have a domainname at all. terminationGracePeriodSeconds <integer> Optional duration in seconds the pod needs to terminate gracefully. May be decreased in delete request. Value must be non-negative integer. The value zero indicates delete immediately. If this value is nil, the default grace period will be used instead. The grace period is the duration in seconds after the processes running in the pod are sent a termination signal and the time when the processes are forcibly halted with a kill signal. Set this value longer than the expected cleanup time for your process. Defaults to 30 seconds. tolerations <[]Object> If specified, the pod's tolerations. volumes <[]Object> List of volumes that can be mounted by containers belonging to the pod. More info: https://kubernetes.io/docs/concepts/storage/volumes
标签操作说明
任何k8s资源都可以打上标, 例如 pod 节点 service等
标签选择器
等值关系 = == !=
集合关系 key in|notin (value1,value2) !key 不存在此key
许多资源支持内嵌字段
matchLabels 直接给定键值
matchExpressions 基于给定的表达式来定义使用的标签选择器 {key:"KEY",operator:"OPERATOR"，values:[val1,val2,...]}
操作符
In, NotIn: values字段的值为非空列表
Exists,NotExists: values字段的值必须为空列表
pod标签过滤器
[root@k8s-master ~]# kubectl label pods pod-demo release=canary pod/pod-demo labeled [root@k8s-master ~]# kubectl get pods -l app --show-labels NAME READY STATUS RESTARTS AGE LABELS pod-demo 2/2 Running 0 1m app=myapp,release=canary,tier=frontend [root@k8s-master ~]# kubectl label pods pod-demo release=canary pod/pod-demo labeled [root@k8s-master ~]# kubectl get pods -l app --show-labels NAME READY STATUS RESTARTS AGE LABELS pod-demo 2/2 Running 0 1m app=myapp,release=canary,tier=frontend [root@k8s-master ~]# kubectl get pods --show-labels NAME READY STATUS RESTARTS AGE LABELS client 1/1 Running 0 1d run=client myapp-74c94dcb8c-dp9t4 1/1 Running 0 4h pod-template-hash=3075087647,run=myapp myapp-74c94dcb8c-jplgj 1/1 Running 0 4h pod-template-hash=3075087647,run=myapp myapp-74c94dcb8c-mjjpw 1/1 Running 0 1d pod-template-hash=3075087647,run=myapp nginx-deploy-5b595999-d7rpg 1/1 Running 0 228d pod-template-hash=16151555,run=nginx-deploy nginx-deploy-5b595999-xkzqz 1/1 Running 0 4h pod-template-hash=16151555,run=nginx-deploy pod-demo 2/2 Running 0 6m app=myapp,release=canary,tier=frontend [root@k8s-master ~]# kubectl get pods -l release NAME READY STATUS RESTARTS AGE pod-demo 2/2 Running 0 4m [root@k8s-master ~]# kubectl get pods -l release,app NAME READY STATUS RESTARTS AGE pod-demo 2/2 Running 0 4m [root@k8s-master ~]# ^C [root@k8s-master ~]# kubectl get pods -l release==canary NAME READY STATUS RESTARTS AGE pod-demo 2/2 Running 0 6m
添加标签
kubectl label pods pod-demo release=canary
查看标签列表信息
kubectl get nodes --show-labels
实现创建的pod运行到指定的节点上 通过节点标签选择器nodeSelector nodeName节点名称选择器
[root@k8s-master ~]# kubectl get pods -o wide NAME pod-demo 2/2 Running 0 29m 10.244.2.16 node3 pod-demo被随机分配到node3节点上 [root@k8s-master mainfests]# kubectl get nodes --show-labels NAME STATUS ROLES AGE VERSION LABELS k8s-master Ready master 228d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=k8s-master,node-role.kubernetes.io/master= node2 Ready <none> 228d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node2 node3 Ready <none> 228d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node3 给node2添加一个独立的标签 [root@k8s-master mainfests]# kubectl label nodes node2 disktype=ssd node/node2 labeled [root@k8s-master mainfests]# kubectl get nodes --show-labels NAME STATUS ROLES AGE VERSION LABELS k8s-master Ready master 228d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=k8s-master,node-role.kubernetes.io/master= node2 Ready <none> 228d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssd,kubernetes.io/hostname=node2 node3 Ready <none> 228d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node3 [root@k8s-master mainfests]# vi pod-demo.yml apiVersion: v1 kind: Pod metadata: name: pod-demo namespace: default labels: app: myapp tier: frontend spec: containers: - name: myapp image: ikubernetes/myapp:v1 - name: busybox image: busybox:latest command: - "/bin/sh" - "-c" - "sleep 50000" nodeSelector: disktype: ssd [root@k8s-master mainfests]# kubectl delete -f pod-demo.yml pod "pod-demo" deleted [root@k8s-master mainfests]# kubectl create -f pod-demo.yml pod/pod-demo created [root@node2 ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 87df5370d6d2 busybox@sha256:4b6ad3a68d34da29bf7c8ccb5d355ba8b4babcad1f99798204e7abb43e54ee3d "/bin/sh -c 'sleep..." 15 seconds ago Up 14 seconds k8s_busybox_pod-demo_default_cd77d89a-7bd4-11e9-9c03-000c2927f194_0 9f1838fa3793 d4a5e0eaa84f "nginx -g 'daemon ..." 28 seconds ago Up 27 seconds k8s_myapp_pod-demo_default_cd77d89a-7bd4-11e9-9c03-000c2927f194_0