The namespaces in Kubernetes provides a way for separating groups of resources hosted within a single cluster.<\/p>\n
While the default namespace where all the pods and applications get hosted is in the “default” namespace, the below command helps to add a new namespace.<\/p>\n
[root@kubmaster01 ~]#<\/strong> kubectl create ns sv-ns1 [root@kubmaster01 ~]#<\/strong> kubectl get ns<\/p>\n ==== ===<\/em> There are two ways to add a new Namespace:<\/p>\n Imperative and declarative Kubernetes commands are the two different methods to configure\u00a0a new namespace. The same applies to configuring several other features too that we will see later.<\/p>\n The method we used to create a new namespace in the above example is\u00a0Imperative<\/em>, where we set the namespace using a CLI. Below is a\u00a0declarative<\/em> method of creating a new namespace, using a yaml manifest file.<\/p>\n [root@CFX-91-KUBEMASTER]#<\/strong> kubectl api-resources | grep namespace [root@kubmaster01 sample]#<\/strong> cat ns2.yml<\/p>\n ====== ===<\/em> [root@kubmaster01 sample]#<\/strong> kubectl create -f ns2.yml [root@kubmaster01 sample]#<\/strong> kubectl get ns<\/p>\n ====== ===<\/em> ===== ===<\/em><\/p>\n The below command is used to explain the parameters used to create a namespace. It is very helpful when creating a namespace using declarative\u00a0method.<\/p>\n [root@kubmaster01 sample]#<\/strong> kubectl explain ns<\/p>\n ===== ==<\/em> DESCRIPTION:<\/em> FIELDS:<\/em> The below command helps to explain in detail the parameters used when configuring metadata section in namespace<\/p>\n [root@kubmaster01 sample]#<\/strong> kubectl explain ns.metadata<\/p>\n The below command explains the detail. But\u00a0–recursive<\/span><\/em><\/strong> prints the same but with more deep details. It also marks the fields that are required<\/em> <\/span>and ones optional<\/span><\/em>.<\/p>\n [root@kubmaster01 ~]#<\/strong> kubectl explain ns.metadata –recursive<\/p>\n ==== ==== DESCRIPTION: FIELDS: [root@CFX-91-KUBEMASTER shiju-manifest-files]# [root@kubmaster01 ~]#<\/strong> kubectl explain ns.metadata –recursive<\/p>\n [root@kubmaster01 ~]#<\/strong> kubectl describe ns sv-ns1<\/p>\n ===== ===<\/em> [root@kubmaster01 ~]#<\/strong> kubectl describe ns sv-ns2<\/p>\n ==== ==== The below command prints the configuration of the namespace in yaml format.<\/p>\n [root@kubmaster01 ~]#<\/strong> kubectl get -o yaml ns sv-ns1<\/p>\n === =========<\/em> ======== Context, Namespace\u00a0and pods<\/span> ========<\/strong><\/p>\n In a Kubernetes cluster there are contexts<\/strong>, and namespaces in each “context”. The namespace in one “context” is entirely different the namespace on another “context”, though the names of the namespace may be similar. Same way, a pod associated to a namespace within a “context”.<\/p>\n Let us change the namepace used in the currect “context” to sv-sn01 using the below command<\/p>\n [root@kubmaster01 sample]#<\/strong> kubectl config set-context –current –namespace sv-ns01 [root@kubmaster01 sample]#<\/strong> kubectl config get-contexts<\/p>\n === ===<\/em> ==== ===<\/em><\/p>\n \u00a0The above command alters the config file used by the user. This config file was initially copied to the users home folder when the below command was run on the master<\/em> node when deploying the cluster<\/p>\n The below command displays the config file in a yaml format.<\/p>\n [root@kubmaster01 ~]#<\/strong> kubectl config view<\/p>\n ===== ===<\/em> ===== ===<\/em><\/p>\n The below command sets the default namespace back to “default”<\/p>\n [root@kubmaster01 ~]#<\/strong> kubectl config set-context –current –namespace default
\nnamespace\/sv-ns1 created<\/p>\n
\nNAME STATUS AGE<\/em>
\ndefault Active 2d15h<\/em>
\nkube-node-lease Active 2d15h<\/em>
\nkube-public Active 2d15h<\/em>
\nkube-system Active 2d15h<\/em>
\nsv-ns1 Active 50s<\/em><\/span>
\n==== ===<\/em><\/p>\n\n
\n===== ====
\nNAME\u00a0 \u00a0 \u00a0 SHORTNAMES\u00a0 \u00a0 \u00a0 APIVERSION\u00a0 \u00a0 \u00a0 NAMESPACED\u00a0 \u00a0 \u00a0KIND
\nnamespaces\u00a0 \u00a0 \u00a0ns\u00a0 \u00a0 \u00a0 v1\u00a0 \u00a0 \u00a0 false\u00a0 \u00a0 \u00a0 Namespace
\n===== ====<\/p>\n
\napiVersion: v1<\/em>
\nkind: Namespace<\/em>
\nmetadata:<\/em>
\n\u00a0 name: sv-ns2<\/em>
\n===<\/em>==<\/p>\n
\nnamespace\/sv-ns2 created<\/p>\n
\nNAME STATUS AGE<\/em><\/strong>
\ndefault<\/span> Active 2d16h<\/em>
\nkube-node-lease Active 2d16h<\/em>
\nkube-public Active 2d16h<\/em>
\nkube-system Active 2d16h<\/em>
\nsv-ns1 Active 46m<\/span><\/em><\/span>
\nsv-ns2 Active 27s<\/span><\/em><\/span><\/p>\n
\nKIND: Namespace<\/em>
\nVERSION: v1<\/em><\/p>\n
\n Namespace provides a scope for Names. Use of multiple namespaces is<\/em>
\n optional.<\/em><\/p>\n
\n apiVersion <string><\/em>
\nAPIVersion defines the versioned schema of this representation of an object.<\/em>
\n Servers should convert recognized schemas<\/em>
\n===== ==<\/em><\/p>\n
\nKIND: Namespace
\nVERSION: v1<\/p>\n
\nNamespace provides a scope for Names. Use of multiple namespaces is
\noptional.<\/p>\n
\napiVersion <string>
\nkind <string>
\nmetadata <ObjectMeta>
\nannotations <map[string]string>
\ncreationTimestamp <string>
\ndeletionGracePeriodSeconds <integer>
\ndeletionTimestamp <string>
\nfinalizers <[]string>
\ngenerateName <string>
\ngeneration <integer>
\nlabels <map[string]string>
\nmanagedFields <[]ManagedFieldsEntry>
\napiVersion <string>
\nfieldsType <string>
\nfieldsV1 <FieldsV1>
\nmanager <string>
\noperation <string>
\nsubresource <string>
\ntime <string>
\nname <string>
\nnamespace <string>
\nownerReferences <[]OwnerReference>
\napiVersion <string> -required-
\nblockOwnerDeletion <boolean>
\ncontroller <boolean>
\nkind <string> -required-
\nname <string> -required-
\nuid <string> -required-
\nresourceVersion <string>
\nselfLink <string>
\nuid <string>
\nspec <NamespaceSpec>
\nfinalizers <[]string>
\nstatus <NamespaceStatus>
\nconditions <[]NamespaceCondition>
\nlastTransitionTime <string>
\nmessage <string>
\nreason <string>
\nstatus <string> -required-
\ntype <string> -required-
\nphase <string><\/p>\n
\n==== =====<\/p>\n
\nName: sv-ns1<\/em>
\nLabels: kubernetes.io\/metadata.name=sv-ns1<\/em>
\nAnnotations: <none><\/em>
\nStatus: Active<\/em>
\nNo resource quota.<\/em>
\nNo LimitRange resource.<\/em>
\n===== ===<\/em><\/p>\n
\nName: sv-ns2
\nLabels: kubernetes.io\/metadata.name=sv-ns2
\nAnnotations: <none>
\nStatus: Active
\nNo resource quota.
\nNo LimitRange resource.
\n===== ===<\/p>\n
\napiVersion: v1<\/em>
\nkind: Namespace<\/em>
\nmetadata:<\/em>
\n\u00a0 \u00a0 \u00a0creationTimestamp: “2024-08-14T07:41:50Z”<\/em>
\n \u00a0 \u00a0 \u00a0labels:<\/em>
\n \u00a0 \u00a0 \u00a0\u00a0 \u00a0 \u00a0kubernetes.io\/metadata.name: sv-ns1<\/em>
\n \u00a0 \u00a0 \u00a0name: sv-ns1<\/em>
\n \u00a0 \u00a0 \u00a0resourceVersion: “57258”<\/em>
\n \u00a0 \u00a0 \u00a0uid: 70bac5da-254d-4ab3-9ce2-b54d55985bcd<\/em>
\nspec:<\/em>
\n \u00a0 \u00a0 \u00a0finalizers:<\/em>
\n \u00a0 \u00a0 \u00a0– kubernetes<\/em>
\nstatus:<\/em>
\n \u00a0 \u00a0 \u00a0phase: Active<\/em>
\n=== =========<\/em><\/p>\n
\nContext “kubernetes-admin@kubernetes” modified.<\/p>\n
\nCURRENT\u00a0 \u00a0 \u00a0NAME\u00a0 \u00a0 \u00a0 \u00a0CLUSTER\u00a0 \u00a0 \u00a0 AUTHINFO\u00a0 \u00a0 \u00a0 NAMESPACE<\/em>
\n* kubernetes-admin@kubernetes\u00a0 \u00a0 \u00a0kubernetes\u00a0 \u00a0 \u00a0 kubernetes-admin\u00a0 \u00a0 sv-ns01<\/em><\/p>\n\n
\napiVersion: v1<\/em>
\nclusters:<\/em>
\n– cluster:<\/em>
\n \u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0certificate-authority-data: DATA+OMITTED<\/em>
\n \u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0server: https:\/\/192.168.146.129:6443<\/em>
\n \u00a0 \u00a0\u00a0name: kubernetes<\/em>
\ncontexts:<\/em>
\n– context:<\/em>
\n \u00a0 \u00a0\u00a0cluster: kubernetes<\/em>
\n \u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0namespace: sv-ns01<\/span><\/em>
\n \u00a0 \u00a0\u00a0user: kubernetes-admin<\/em>
\n \u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0name: kubernetes-admin@kubernetes<\/em>
\ncurrent-context: kubernetes-admin@kubernetes<\/em>
\nkind: Config<\/em>
\npreferences: {}<\/em>
\nusers:<\/em>
\n\u00a0 \u00a0\u00a0– name: kubernetes-admin<\/em>
\n \u00a0 \u00a0\u00a0user:<\/em>
\n\u00a0 \u00a0\u00a0\u00a0 \u00a0 client-certificate-data: DATA+OMITTED<\/em>
\n \u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0client-key-data: DATA+OMITTED<\/em><\/p>\n
\nContext “kubernetes-admin@kubernetes” modified.<\/p>\n","protected":false},"excerpt":{"rendered":"