Kubernetes - namespace (네임스페이스)

namespace란?

namepace 정의

• 클러스터 하나를 여러 개의 논리적인 단위로 나누어서 사용
• 쿠버네티스 클러스터 하나를 여러 팀이나 사용자가 함께 공유
• 용도에 따라 실행해야 하는 앱을 구분할 때 사용

namepace 명령어

namespace 조회

root@master:~# kubectl get namespaces
NAME              STATUS   AGE
default           Active   3d23h
kube-node-lease   Active   3d23h
kube-public       Active   3d23h
kube-system       Active   3d23h

namespace 생성

root@master:~# kubectl create namespace blue
namespace/blue created
root@master:~# kubectl get namespaces 
NAME              STATUS   AGE
blue              Active   6s
default           Active   3d23h
kube-node-lease   Active   3d23h
kube-public       Active   3d23h
kube-system       Active   3d23h

namespace 삭제

root@master:~# kubectl delete namespaces blue
namespace "blue" deleted
root@master:~# kubectl get namespaces 
NAME              STATUS   AGE
default           Active   3d23h
kube-node-lease   Active   3d23h
kube-public       Active   3d23h
kube-system       Active   3d23h

namespace 생성 (yaml)

root@master:~# kubectl create namespace orange --dry-run -o yaml > orange-ns.yaml
W1115 21:46:37.369391   11945 helpers.go:555] --dry-run is deprecated and can be replaced with --dry-run=client.
root@master:~# cat orange-ns.yaml 
apiVersion: v1
kind: Namespace
metadata:
  creationTimestamp: null
  name: orange
spec: {}
status: {}
root@master:~# kubectl get namespaces 
NAME              STATUS   AGE
default           Active   3d23h
kube-node-lease   Active   3d23h
kube-public       Active   3d23h
kube-system       Active   3d23h
root@master:~# kubectl create -f orange-ns.yaml 
namespace/orange created
root@master:~# kubectl get namespaces 
NAME              STATUS   AGE
default           Active   3d23h
kube-node-lease   Active   3d23h
kube-public       Active   3d23h
kube-system       Active   3d23h
orange            Active   2s

namespace 지정하여 pod 생성

root@master:~# kubectl create -f nginx.yaml -n orange 
pod/nginx created
root@master:~# kubectl get pods -n default
No resources found in default namespace.
root@master:~# kubectl get pods -n orange
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          11s

namespace 지정하여 pod 삭제

root@master:~# kubectl delete pod nginx
Error from server (NotFound): pods "nginx" not found
root@master:~# kubectl delete pod nginx -n orange
pod "nginx" deleted

namepace 스위치

config 정보 조회

root@master:~# kubectl config view
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: https://10.100.0.104:6443
  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:
    client-certificate-data: REDACTED
    client-key-data: REDACTED

현재 context 조회

root@master:~# kubectl config current-context
kubernetes-admin@kubernetes

namespace 포함하여 context 등록

root@master:~# kubectl config set-context blue@kubernetes --cluster=kubernetes --user=kubernetes-admin --namespace=blue
Context "blue@kubernetes" created.

context 변경

root@master:~# kubectl config use-context blue@kubernetes
Switched to context "blue@kubernetes".
root@master:~# kubectl config current-context 
blue@kubernetes

pod 생성

namespace 지정을 하지 않아도 변경된 기본 blue namespace에 생성이 됨

root@master:~# kubectl create -f nginx.yaml 
pod/nginx created
root@master:~# kubectl get pods -n blue
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          19s
root@master:~# kubectl get pods 
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          25s