为了方便归类和管理，在kubernetes中标签管理也至为重要
labels标签管理
一个资源可以拥有多个标签，同一个标签可以被添加到多个对象，标签可以在创建资源时指定，并且可以在之后进行添加和删除，以及修改
labels:
www: linuxea-com如上所示，类型key=value，其中键和值的长度最多使用63个字符
- key
其中key只能使用字母，数字，下划线(_)，减号(-)，点(.)，并且只能使用字母开头在使用键时，可以使用键前缀，前缀总长度不能超过253个字符。
- value
其中value长度也不能超过253个字符，但是可以为空。也就是说可以有key，value可以为空。并且只能以字母或数字开头以及结尾，中间可以使用字母，数字，下划线(_)，减号(-)，点(.)这当中，标签至少满足一点，见名知意
为了充分利用这些标签，每个标签见名知意，以应用程序名称，标识应用程序实例的唯一名称，版本，组件等。如下示例:
标签查看
此前使用kubectl get pods --show-labels可观察到所有pod的标签
[root@linuxea linuxea]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client-linuxea 1/1 Running 0 2d run=client-linuxea
nginx-linuxea-5786698598-dx2jr 1/1 Running 0 33s pod-template-hash=1342254154,run=nginx-linuxea
nginx-linuxea-5786698598-stttv 1/1 Running 0 33s pod-template-hash=1342254154,run=nginx-linuxea
nginx-linuxea-5786698598-t6lpx 1/1 Running 0 33s pod-template-hash=1342254154,run=nginx-linuxea
pod-demo-linuxea 3/3 Running 0 21m tier=backend,www=linuxea-com列出www的标签的标签值的pods: -L选项
[root@linuxea linuxea]# kubectl get pods -L=www
NAME READY STATUS RESTARTS AGE WWW
client-linuxea 1/1 Running 0 2d
nginx-linuxea-5786698598-dx2jr 1/1 Running 0 20s
nginx-linuxea-5786698598-stttv 1/1 Running 0 20s
nginx-linuxea-5786698598-t6lpx 1/1 Running 0 20s
pod-demo-linuxea 3/3 Running 0 21m linuxea-com并且可以显示多个标签值,如：显示包含www标签和run状态的pods
[root@linuxea linuxea]# kubectl get pods -L=www,run
NAME READY STATUS RESTARTS AGE WWW RUN
client-linuxea 1/1 Running 0 2d client-linuxea
nginx-linuxea-5786698598-dx2jr 1/1 Running 0 3s nginx-linuxea
nginx-linuxea-5786698598-stttv 1/1 Running 0 3s nginx-linuxea
nginx-linuxea-5786698598-t6lpx 1/1 Running 0 3s nginx-linuxea
pod-demo-linuxea 3/3 Running 0 20m linuxea-com 那么如果只想显示www标签的pods，使用小l： -l，并且可以接上--show-labels
[root@linuxea linuxea]# kubectl get pods -l=www
NAME READY STATUS RESTARTS AGE
pod-demo-linuxea 3/3 Running 0 16m[root@linuxea linuxea]# kubectl get pods -l=www --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo-linuxea 3/3 Running 0 15m tier=backend,www=linuxea-com标签打包
事先创建了pod-demo-linuxea，此刻添加一个标签version=20180808
[root@linuxea linuxea]# kubectl label pods pod-demo-linuxea version=20180808
pod/pod-demo-linuxea labeled[root@linuxea linuxea]# kubectl get pods -l=www --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo-linuxea 3/3 Running 0 22m tier=backend,version=20180808,www=linuxea-com此刻标签已经打上，可是现在要进行更改，如果要 更改就要使用--overwrite覆盖将version=20180808改成version=20180809，方式覆盖
[root@linuxea linuxea]# kubectl label pods pod-demo-linuxea version=20180809 --overwrite
pod/pod-demo-linuxea labeled[root@linuxea linuxea]# kubectl get pods -l=www --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo-linuxea 3/3 Running 0 13h tier=backend,version=20180809,www=linuxea-com标签的选择器
等值关系标签选择器：=(等于)，==(等于)，!=(不等于)集合关系标签选择器： Key in (VALUE1,VALUE2,...)
Key notin (VALUE1,VALUE2,...)
Key 存在次键
!Key 不存在次键其中，在标签选择器中可以指定多个选择条件，在多个条件中隐含了逻辑域如果使用空的标签，则都符合选择
- 等值关系示例：
等于
[root@linuxea linuxea]# kubectl get pods -l version=20180809 --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo-linuxea 3/3 Running 0 14h tier=backend,version=20180809,www=linuxea-com不等于
[root@linuxea linuxea]# kubectl get pods -l version!=20180809 --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client-linuxea 1/1 Running 0 2d run=client-linuxea
nginx-linuxea-5786698598-dx2jr 1/1 Running 0 14h pod-template-hash=1342254154,run=nginx-linuxea
nginx-linuxea-5786698598-stttv 1/1 Running 0 14h pod-template-hash=1342254154,run=nginx-linuxea
nginx-linuxea-5786698598-t6lpx 1/1 Running 0 14h pod-template-hash=1342254154,run=nginx-linuxea
[root@linuxea linuxea]# - 集合关系示例：
查找version的值是20180809，以及20180810
[root@linuxea linuxea]# kubectl get pods -l "version in (20180809，20180910)" --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo-linuxea 3/3 Running 0 15h tier=backend,version=20180809,www=linuxea-com
[root@linuxea linuxea]# 查找version的值是20180809和20180810以外的
[root@linuxea linuxea]# kubectl get pods -l "version notin (20180809，20180810)" --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client-linuxea 1/1 Running 0 2d run=client-linuxea
nginx-linuxea-5786698598-dx2jr 1/1 Running 0 14h pod-template-hash=1342254154,run=nginx-linuxea
nginx-linuxea-5786698598-stttv 1/1 Running 0 14h pod-template-hash=1342254154,run=nginx-linuxea
nginx-linuxea-5786698598-t6lpx 1/1 Running 0 14h pod-template-hash=1342254154,run=nginx-linuxea
pod-demo-linuxea 3/3 Running 0 15h tier=backend,version=20180809,www=linuxea-com标签关联
通常，在pod和service中会做一些标签关联，会使用另外两个字段来.许多资源支持内嵌字段，其使用的标签选择器如下：
- matchLabels: 直接给定键值
-
matchExpressions: 基于给定的表达式来定义使用标签选择器，{key:"KEY",operator:"OPERATOR",values:[VAL1,VAL2,.....]} 操作符
In，NotIn: values字段必须为非空列表 Exists,NotExists： values字段必须为空列表node标签
nodeSelector：节点标签选择器，简单的打标：
wwwtype=www.linuxea.com[root@linuxea linuxea]# kubectl label nodes linuxea.node-3.com wwwtype=www.linuxea.com node/linuxea.node-3.com labeled查看
wwwtype=www.linuxea.com，是对应到linuxea.node-3.com的nodes上[root@linuxea linuxea]# kubectl get nodes --show-labels NAME STATUS ROLES AGE VERSION LABELS linuxea.master-1.com Ready master 3d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=linuxea.master-1.com,node-role.kubernetes.io/master= linuxea.node-1.com Ready <none> 3d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=linuxea.node-1.com linuxea.node-2.com Ready <none> 3d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=linuxea.node-2.com linuxea.node-3.com Ready <none> 3d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=linuxea.node-3.com,men=8G,wwwtype=www.linuxea.com而后在yaml文件中指定
nodeSelector: wwwtype: www.linuxea.com与spec下的containers同级，示例如下：
apiVersion: v1 kind: Pod metadata: name: pod-demo-linuxea namespace: default labels: www: linuxea-com tier: backend spec: containers: - name: linuxea-pod1-com image: "marksugar/nginx:1.14.a" ports: - containerPort: 88 - name: linuxea-pod2-com image: "marksugar/nginx:1.14.b" ports: - containerPort: 88 - name: alpine image: "alpine:3.8" command: - "/bin/sh" - "-c" - "tail -f /etc/passwd" nodeSelector: wwwtype: www.linuxea.com而后
kubectl create -f pod-demo.yaml[root@linuxea linuxea]# kubectl create -f pod-demo.yaml pod/pod-demo-linuxea created在次观察，
pod-demo.yaml已经添加到linuxea.node-3.com[root@linuxea linuxea]# kubectl get pods -o wide --show-labels NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE LABELS client-linuxea 1/1 Running 0 2d 172.16.2.252 linuxea.node-2.com <none> run=client-linuxea nginx-linuxea-5786698598-dx2jr 1/1 Running 0 15h 172.16.2.11 linuxea.node-2.com <none> pod-template-hash=1342254154,run=nginx-linuxea nginx-linuxea-5786698598-stttv 1/1 Running 0 15h 172.16.1.15 linuxea.node-1.com <none> pod-template-hash=1342254154,run=nginx-linuxea nginx-linuxea-5786698598-t6lpx 1/1 Running 0 15h 172.16.3.25 linuxea.node-3.com <none> pod-template-hash=1342254154,run=nginx-linuxea pod-demo-linuxea 3/3 Running 0 2s 172.16.3.26 linuxea.node-3.com <none> tier=backend,www=linuxea-com而后
kubectl describe pods pod-demo-linuxea |tail -15查看倒数15行的信息[root@linuxea linuxea]# kubectl describe pods pod-demo-linuxea |tail -15 Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s node.kubernetes.io/unreachable:NoExecute for 300s Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 50s default-scheduler Successfully assigned default/pod-demo-linuxea to linuxea.node-3.com Normal Pulled 49s kubelet, linuxea.node-3.com Container image "marksugar/nginx:1.14.a" already present on machine Normal Created 49s kubelet, linuxea.node-3.com Created container Normal Started 49s kubelet, linuxea.node-3.com Started container Normal Pulled 49s kubelet, linuxea.node-3.com Container image "marksugar/nginx:1.14.b" already present on machine Normal Created 49s kubelet, linuxea.node-3.com Created container Normal Started 48s kubelet, linuxea.node-3.com Started container Normal Pulled 48s kubelet, linuxea.node-3.com Container image "alpine:3.8" already present on machine Normal Created 48s kubelet, linuxea.node-3.com Created container Normal Started 48s kubelet, linuxea.node-3.com Started container资源注解
annotations : annotations与label的区别在于 : 它不能用于标签的选择器，仅用于为对象提供"元数据"。这些数据有些时候会被某些程序用到，键值不受长度限制。在声明时会被用上
[root@linuxea linuxea]# kubectl describe pods pod-demo-linuxea |grep Annotations Annotations: <none> [root@linuxea linuxea]#可见现在没有配置。删除后添加
[root@linuxea linuxea]# kubectl delete -f pod-demo.yaml pod "pod-demo-linuxea" deleted编辑资源清单添加
annotations: www.linuxea.com/ops-by: "linuxea admin"完整如下
apiVersion: v1 kind: Pod metadata: name: pod-demo-linuxea namespace: default labels: www: linuxea-com tier: backend annotations: www.linuxea.com/ops-by: "linuxea admin" spec: containers: - name: linuxea-pod1-com image: "marksugar/nginx:1.14.a" ports: - containerPort: 88 - name: linuxea-pod2-com image: "marksugar/nginx:1.14.b" ports: - containerPort: 88 - name: alpine image: "alpine:3.8" command: - "/bin/sh" - "-c" - "tail -f /etc/passwd" nodeSelector: wwwtype: www.linuxea.com开始create
[root@linuxea linuxea]# kubectl create -f pod-demo.yaml pod/pod-demo-linuxea created[root@linuxea linuxea]# kubectl describe pods pod-demo-linuxea |grep Annotations Annotations: www.linuxea.com/ops-by=linuxea admin
