Namespaces

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• Namespaces groups resources to provide isolation between them.
• Its a way to divide cluster resources between multiple users (via Resource Quotas)
• It can be used for separating resources between projects or applying quotas.
• Resource names must be unique within a namespace but can be duplicated across namespaces.

apiVersion: v1
kind: Namespace
metadata: 
  name: dev

• Create resources in namespace by specify it in metadata field

apiVersion: v1
kind: Pod
metadata:
  name: server
  namespace: dev #Create Pod in dev namespace
  labels:
    app: webserver
    env: prod
spec:
    containers:
      - name: nginx
        image: nginx

Types of Namespaces

1. default: by default creates resources in this namespace when no namespace is specified
2. kube-system: reserved for Kubernetes system components
3. kube-public: used for cluster-wide public resources
4. kube-node-lease: Holds node lease objects for node heartbeats

Commands

1. create namespace without YAML (imperative command)

kubectl create namespace <name>

2. create namespace with YAML (declarative command)

kubectl create -f namespace-definition.yaml

3. set context for namespace

kubectl config set-context $(kubectl config current-context) --namespace=dev

Related

• Linux kernel namespaces

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⬅️ Namespaces | ➡️

References

1. https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/