Label management of kubernetes cluster

One 、Label Introduce

1. The label is k8s Characteristic management way , Easy to classify and manage resource objects .
2. A tag can correspond to multiple resources , A resource can also have multiple tags , They are many to many relationships .
3. A special resource object , Must be attached to a specific resource object , Used to identify the purpose of the resource object .
4. A resource has multiple tags , Can achieve different dimensions of Management .

Two 、 Check local k8s State of the cluster

[[email protected]-master ~]# kubectl get nodes -owide
NAME         STATUS   ROLES                  AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION          CONTAINER-RUNTIME
k8s-master   Ready    control-plane,master   18h   v1.23.1   192.168.3.201   <none>        CentOS Linux 7 (Core)   3.10.0-957.el7.x86_64   containerd://1.6.6
k8s-node01   Ready    <none>                 18h   v1.23.1   192.168.3.202   <none>        CentOS Linux 7 (Core)   3.10.0-957.el7.x86_64   containerd://1.6.6
k8s-node02   Ready    <none>                 18h   v1.23.1   192.168.3.203   <none>        CentOS Linux 7 (Core)   3.10.0-957.el7.x86_64   containerd://1.6.6

3、 ... and 、Label The creation of

1. Add a label to the work node

[[email protected]-master ~]# kubectl label nodes k8s-node02 fun=work02
node/k8s-node02 labeled

2. to pod tagged

[[email protected]-master ~]# kubectl label pod cirror-28253 fun=ittest
pod/cirror-28253 labeled
[[email protected]-master ~]# kubectl label pod cirror-28253 env=proc
pod/cirror-28253 labeled

3. Label the work node with role

[[email protected]-master ~]# kubectl label nodes k8s-node01  node-role.kubernetes.io/worker=
node/k8s-node01 labeled

Four 、Label Modification of

Modify the label

[[email protected]-master ~]# kubectl label nodes k8s-node02 fun=node02  --overwrite 
node/k8s-node02 labeled

5、 ... and 、Label Query for

1. List all labels of the node

[[email protected]-master ~]# kubectl get nodes --show-labels 
NAME         STATUS   ROLES                  AGE   VERSION   LABELS
k8s-master   Ready    control-plane,master   18h   v1.23.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-master,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
k8s-node01   Ready    worker                 18h   v1.23.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-node01,kubernetes.io/os=linux,node-role.kubernetes.io/worker=
k8s-node02   Ready    <none>                 18h   v1.23.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,fun=node02,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-node02,kubernetes.io/os=linux,type=dell730

2. Query with worker Nodes of a role

[[email protected]-master ~]# kubectl get nodes -l node-role.kubernetes.io/worker
NAME         STATUS   ROLES    AGE   VERSION
k8s-node01   Ready    worker   18h   v1.23.1

3. Query with type Node of label

[[email protected]-master ~]# kubectl get nodes -l type
NAME         STATUS   ROLES    AGE   VERSION
k8s-node02   Ready    <none>   18h   v1.23.1

6、 ... and 、Label The deletion of

[[email protected]-master ~]# kubectl label nodes k8s-node02 fun-
node/k8s-node02 unlabeled
[[email protected]-master ~]# kubectl get node -l fun
No resources found

7、 ... and 、kubernetes Annotations use

1. Add notes to the work node

[[email protected]-master ~]# kubectl annotate nodes k8s-node01 test="this is a work node"
node/k8s-node01 annotated

2. View comments

[[email protected]-master ~]# kubectl describe nodes k8s-node01 |grep test
                    test: this is a work node

3. Modify the note

 kubectl annotate nodes k8s-node01 test=11 --overwrite

4. Delete comments

kubectl annotate nodes k8s-node01 test-

8、 ... and 、 stay yaml Label usage of script

[[email protected]-master ~]#  kubectl run web01 --image=nginx:1.21 -n k8s-test  -o yaml --dry-run=client
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: web01
  name: web01
  namespace: k8s-test
spec:
  containers:
  - image: nginx:1.21
    name: web01
    resources: {
    }
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {
    }