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K8s-命名空间

发表于 分类于 ，

一、命名空间(namespace)作用

  • Namespace是对一组资源和对象的抽象集合.
  • 常见的 pod, service, deployment 等都是属于某一个namespace的（默认是 default）
  • 不是所有资源都属于namespace，如nodes, persistent volume，namespace 等资源则不属于任何 namespace

二、查看namespace

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[root@k8s-master1 ~]# kubectl get namespaces       # namespaces可以简写为namespace或ns
NAME              STATUS   AGE
default           Active   130m         # 所有未指定Namespace的对象都会被默认分配在default命名空间
kube-node-lease   Active   130m         
kube-public       Active   130m         # 此命名空间下的资源可以被所有人访问
kube-system       Active   130m         # 所有由Kubernetes系统创建的资源都处于这个命名空间

三、查看namespace里的资源

使用kubectl get all --namespace=命名空间名称可以查看此命名空间下的所有资源

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[root@k8s-master1 ~]# kubectl get all --namespace=kube-system
NAME                                             READY   STATUS    RESTARTS   AGE
pod/calico-kube-controllers-7fdc86d8ff-cskfq     1/1     Running   3          5d1h
pod/calico-node-9dpc9                            1/1     Running   2          5d1h
pod/calico-node-jdmxw                            1/1     Running   3          5d1h
pod/calico-node-krwps                            1/1     Running   2          5d1h
pod/calico-node-tttlr                            1/1     Running   2          5d1h
pod/coredns-65dbdb44db-mm7cr                     1/1     Running   2          5d1h
pod/dashboard-metrics-scraper-545bbb8767-q66bc   1/1     Running   2          5d1h
pod/kubernetes-dashboard-65665f84db-nll6k        1/1     Running   4          5d1h
pod/metrics-server-869ffc99cd-8f4jd              1/1     Running   3          5d1h

NAME                                TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                  AGE
service/dashboard-metrics-scraper   ClusterIP   10.2.246.128   <none>        8000/TCP                 5d1h
service/kube-dns                    ClusterIP   10.2.0.2       <none>        53/UDP,53/TCP,9153/TCP   5d1h
service/kubernetes-dashboard        NodePort    10.2.213.30    <none>        443:21351/TCP            5d1h
service/metrics-server              ClusterIP   10.2.232.121   <none>        443/TCP                  5d1h

NAME                         DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR                 AGE
daemonset.apps/calico-node   4         4         4       4            4           beta.kubernetes.io/os=linux   5d1h

NAME                                        READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/calico-kube-controllers     1/1     1            1           5d1h
deployment.apps/coredns                     1/1     1            1           5d1h
deployment.apps/dashboard-metrics-scraper   1/1     1            1           5d1h
deployment.apps/kubernetes-dashboard        1/1     1            1           5d1h
deployment.apps/metrics-server              1/1     1            1           5d1h

NAME                                                   DESIRED   CURRENT   READY   AGE
replicaset.apps/calico-kube-controllers-7fdc86d8ff     1         1         1       5d1h
replicaset.apps/coredns-65dbdb44db                     1         1         1       5d1h
replicaset.apps/dashboard-metrics-scraper-545bbb8767   1         1         1       5d1h
replicaset.apps/kubernetes-dashboard-65665f84db        1         1         1       5d1h
replicaset.apps/metrics-server-869ffc99cd              1         1         1       5d1h

使用kubectl get 资源类型 --namespace=命名空间名称可以查看此命名空间下的对应的资源

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[root@k8s-master1 ~]# kubectl get pod --namespace=kube-system
NAME                                         READY   STATUS    RESTARTS   AGE
calico-kube-controllers-7fdc86d8ff-cskfq     1/1     Running   3          5d1h
calico-node-9dpc9                            1/1     Running   2          5d1h
calico-node-jdmxw                            1/1     Running   3          5d1h
calico-node-krwps                            1/1     Running   2          5d1h
calico-node-tttlr                            1/1     Running   2          5d1h
coredns-65dbdb44db-mm7cr                     1/1     Running   2          5d1h
dashboard-metrics-scraper-545bbb8767-q66bc   1/1     Running   2          5d1h
kubernetes-dashboard-65665f84db-nll6k        1/1     Running   4          5d1h
metrics-server-869ffc99cd-8f4jd              1/1     Running   3          5d1h

使用kubectl get 资源类型 -A ，查看所有命名空间的资源

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[root@k8s-master01 kubernetes]# kubectl get pods -A
NAMESPACE          NAME                                       READY   STATUS    RESTARTS   AGE
calico-apiserver   calico-apiserver-665569779-4wr5l           1/1     Running   0          6h27m
calico-apiserver   calico-apiserver-665569779-r76t6           1/1     Running   0          6h27m
calico-system      calico-kube-controllers-78687bb75f-46l2t   1/1     Running   0          6h29m
calico-system      calico-node-f9gx6                          1/1     Running   0          5h58m
calico-system      calico-node-rsk4w                          1/1     Running   0          5h58m
calico-system      calico-node-xfr2n                          1/1     Running   0          6h29m
calico-system      calico-typha-75444c4b8-4x7pp               1/1     Running   0          5h58m
calico-system      calico-typha-75444c4b8-nmmj5               1/1     Running   0          6h29m
calico-system      csi-node-driver-4l2ts                      2/2     Running   0          5h56m
calico-system      csi-node-driver-92q4k                      2/2     Running   0          6h28m
calico-system      csi-node-driver-kcw5b                      2/2     Running   0          5h57m
kube-system        coredns-558bd4d5db-5j4gq                   1/1     Running   0          16h
kube-system        coredns-558bd4d5db-79qsm                   1/1     Running   0          16h
kube-system        etcd-k8s-master01                          1/1     Running   0          16h
kube-system        kube-apiserver-k8s-master01                1/1     Running   0          16h
kube-system        kube-controller-manager-k8s-master01       1/1     Running   0          16h
kube-system        kube-proxy-v2ltp                           1/1     Running   0          16h
kube-system        kube-proxy-wzxps                           1/1     Running   0          5h58m
kube-system        kube-proxy-zr77d                           1/1     Running   0          5h58m
kube-system        kube-scheduler-k8s-master01                1/1     Running   0          16h
tigera-operator    tigera-operator-6f669b6c4f-qmdbc           1/1     Running   0          6h37m

四、创建namespace

4.1 命令创建

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[root@k8s-master1 ~]# kubectl create namespace ns1
namespace/ns1 created

[root@k8s-master1 ~]# kubectl get ns
NAME              STATUS   AGE
default           Active   5d1h
kube-node-lease   Active   5d1h
kube-public       Active   5d1h
kube-system       Active   5d1h
ns1               Active   10s

4.2 YAML文件创建

  • k8s中几乎所有的资源都可以通这YAML编排来创建

编写创建namespace的YAML文件

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[root@k8s-master1 ~]# vim create_ns2.yml
apiVersion: v1                          # api版本号
kind: Namespace                         # 类型为namespace
metadata:                               # 定义namespace的元数据属性
  name: ns2                             # 定义name属性为ns2

使用kubctl apply -f应用YAML文件

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[root@k8s-master1 ~]# kubectl apply -f create_ns2.yml
namespace/ns2 created

[root@k8s-master1 ~]# kubectl get ns
NAME              STATUS   AGE
default           Active   5d2h
kube-node-lease   Active   5d2h
kube-public       Active   5d2h
kube-system       Active   5d2h
ns1               Active   10m
ns2               Active   46s
  • 可以使用 kubectl edit 资源类型 资源名 编辑资源的YAML语法
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[root@k8s-master1 ~]# kubectl edit namespace ns1
......
  • 也可使用 kubectl get 资源类型 资源名 -o yaml来查看
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[root@k8s-master1 ~]# kubectl get ns ns1 -o yaml
......
  • 还可通过kubectl explain 资源类型来查看语法文档
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[root@k8s-master1 ~]# kubectl explain namespace                # 查看namespace相关语法参数
[root@k8s-master1 ~]# kubectl explain namespace.metadata       # 查看namespace下级metadata的相关语法参数
[root@k8s-master1 ~]# kubectl explain namespace.metadata.name  # 查看namespace下级metadata再下级name的相关语法参数

五、删除namespace

注意:

  • 删除一个namespace会自动删除所有属于该namespace的资源(类似mysql中drop库会删除库里的所有表一样，请慎重操作)
  • default,kube-system,kube-public命名空间不可删除

5.1 命令删除

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[root@k8s-master1 ~]# kubectl delete namespace ns1
namespace "ns1" deleted

5.2 YAML文件删除

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[root@k8s-master1 ~]# kubectl delete -f create_ns2.yml
namespace "ns2" deleted

[root@k8s-master1 ~]# kubectl get ns
NAME              STATUS   AGE
default           Active   5d2h
kube-node-lease   Active   5d2h
kube-public       Active   5d2h
kube-system       Active   5d2h