> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Solution Services optional > This lesson covers inspecting and creating services in a Kubernetes cluster to expose a web application. In this lesson, we will walk through the solution for the lab on Services. You will learn how to inspect different aspects of services in a Kubernetes cluster and create a service to expose a web application. This guide is designed to help you understand Kubernetes Services, their types, endpoints, and best practices for deployment. *** ## Listing Kubernetes Services To start, list the services in your cluster. You can use either of the following commands: ```bash theme={null} kubectl get service ``` or ```bash theme={null} kubectl get svc ``` For example, running: ```bash theme={null} kubectl get service ``` produces the output: ```bash theme={null} NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m ``` This output indicates that only the default Kubernetes service is present. Below is an extended example using both commands: ```bash theme={null} controlplane ~ ⟪ kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m controlplane ~ ⟪ kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m controlplane ~ ⟪ ``` The default Kubernetes service is automatically created and managed by the system. *** ## Inspecting the Default Kubernetes Service Next, inspect the default Kubernetes service to review its type and configuration. Running the following commands reveals that the service type is ClusterIP: ```bash theme={null} controlplane ~ ➜ kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m controlplane ~ ➜ kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m controlplane ~ ➜ ``` To inspect the target port configured on this service, use the `kubectl describe` command as shown below: ```bash theme={null} controlplane ~ ⇨ kubectl describe svc kubernetes Name: kubernetes Namespace: default Labels: component=apiserver provider=kubernetes Annotations: Selector: Type: ClusterIP IP Family Policy: SingleStack IP Families: IPv4 IP: 10.43.0.1 IPs: 10.43.0.1 Port: 443/TCP TargetPort: 6443/TCP Endpoints: 10.53.180.9:6443 Session Affinity: None Events: controlplane ~ ⇨ # ``` From this output, you can see that the target port is set to 6443. *** ## Understanding Labels and Endpoints The Kubernetes service is labeled with key-value pairs that identify the API server: * `component=apiserver` * `provider=kubernetes` These labels help in managing and identifying the components of the cluster. Endpoints, on the other hand, define the pods that receive traffic from the service. Even if multiple pods match the selector criteria, the service lists all endpoints. In our case, the Kubernetes service shows one endpoint: ```bash theme={null} controlplane ~ ⟩ kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m controlplane ~ ⟩ kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.43.0.1 443/TCP 10m controlplane ~ ⟩ kubectl describe svc kubernetes Name: kubernetes Namespace: default Labels: component=apiserver provider=kubernetes Annotations: Selector: Type: ClusterIP IP Family Policy: SingleStack IP Families: IPv4 IP: 10.43.0.1 IPs: 10.43.0.1 Port: 443/TCP TargetPort: 6443/TCP Endpoints: 10.53.180.9:6443 Session Affinity: None Events: controlplane ~ ⟩ ``` Endpoints represent the set of pod IP addresses and ports that receive traffic from the service. If the service’s selector mistakenly does not match any pods, the endpoints list will be empty. An illustrative diagram outlines how endpoints connect to pods: ![A hand-drawn diagram with a triangle connected to four circles, labeled "app: FE" and "app: FG," possibly representing a network or system architecture.](https://kodekloud.com/kk-media/image/upload/v1752869753/notes-assets/images/CKA-Certification-Course-Certified-Kubernetes-Administrator-Solution-Services-optional/frame_290.jpg) *** ## Inspecting Deployments Now, let’s examine deployments within the default namespace. To list all deployments, run: ```bash theme={null} controlplane ~ -> kubectl get deploy NAME READY UP-TO-DATE AVAILABLE AGE simple-webapp-deployment 0/4 4 0 15s ``` This output indicates that a deployment named `simple-webapp-deployment` exists. ### Reviewing Deployment Details To check details—such as the container image used—describe the deployment: ```bash theme={null} controlplane ~ ➜ kubectl describe deploy simple-webapp-deployment Name: simple-webapp-deployment Namespace: default CreationTimestamp: Fri, 15 Apr 2022 20:35:47 +0000 Labels: Annotations: deployment.kubernetes.io/revision: 1 Selector: name=simple-webapp Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable StrategyType: RollingUpdate MinReadySeconds: 0 RollingUpdateStrategy: 25% max unavailable, 25% max surge Pod Template: Labels: name=simple-webapp Containers: simple-webapp: Image: kodekloud/simple-webapp:red Port: 8080/TCP Host Port: 0/TCP Environment: Mounts: Conditions: Type Status Reason ---- ------ ------- Available True MinimumReplicasAvailable Progressing True NewReplicaSetAvailable OldReplicaSet: NewReplicaSet: simple-webapp-deployment-7b59598d59 (4/4 replicas created) Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal ScalingReplicaSet 63s deployment-controller Scaled up replica set simple-webapp-deployment- ``` The output confirms that the image used is `kodekloud/simple-webapp:red`. ### Accessing the Web Application UI If you attempt to access the web application UI without first exposing it through a service, you may encounter a "Bad Gateway" error. This occurs because no service directs traffic to your pods. ```bash theme={null} controlplane ~ -> kubectl get deploy NAME READY UP-TO-DATE AVAILABLE AGE simple-webapp-deployment 0/4 4 0 15s controlplane ~ -> kubectl describe deploy simple-webapp-deployment Name: simple-webapp-deployment Namespace: default CreationTimestamp: Fri, 15 Apr 2022 20:35:47 +0000 Labels: Annotations: deployment.kubernetes.io/revision: 1 Selector: name=simple-webapp Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable StrategyType: RollingUpdate MinReadySeconds: 0 RollingUpdateStrategy: 25% max unavailable, 25% max surge Pod Template: Labels: name=simple-webapp Containers: simple-webapp: Image: kodekloud/simple-webapp:red Port: 8080/TCP Host Port: 0/TCP Environment: Mounts: Conditions: Type Status Reason ---- ------ ------- Available True MinimumReplicasAvailable Progressing True NewReplicaSetAvailable OldReplicaSet: NewReplicaSet: simple-webapp-deployment-7b59598d59 (4/4 replicas created) Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal ScalingReplicaSet 63s deployment-controller Scaled up replica set simple-webapp-deployment- ``` To resolve this, create a service that exposes the web application. *** ## Creating a Service for the Web Application The next step is to create a NodePort service that makes the web application accessible. The diagram below shows the service definition framework: ![The image shows a terminal interface with instructions to create a NodePort service for a web application, specifying ports and a selector.](https://kodekloud.com/kk-media/image/upload/v1752869755/notes-assets/images/CKA-Certification-Course-Certified-Kubernetes-Administrator-Solution-Services-optional/frame_440.jpg) Below is the basic framework for the service YAML file: ```yaml theme={null} apiVersion: v1 kind: Service metadata: name: spec: type: ports: - targetPort: port: nodePort: selector: name: ``` For further guidance, consult the [Kubernetes documentation](https://kubernetes.io/docs/concepts/services-networking/service/) on services. An example service YAML provided in the docs is shown below: ```yaml theme={null} apiVersion: v1 kind: Service metadata: name: my-service spec: selector: app: MyApp ports: - protocol: TCP port: 80 targetPort: 9376 ``` For this lab, create a NodePort service named `webapp-service` that exposes your web application on port 8080. The final service definition is as follows: ```yaml theme={null} apiVersion: v1 kind: Service metadata: name: webapp-service spec: type: NodePort ports: - targetPort: 8080 port: 8080 nodePort: 30080 selector: name: simple-webapp ``` Save this configuration as your service definition file (for example, `service-definition-1.yaml`) and then run the following commands to create the service: ```bash theme={null} controlplane ~ ✗ ls service-definition-1.yaml controlplane ~ ✗ cat service-definition-1.yaml --- apiVersion: v1 kind: Service metadata: name: spec: type: ports: - targetPort: port: nodePort: selector: name: controlplane ~ ✗ vi service-definition-1.yaml controlplane ~ ✗ kubectl create -f service-definition-1.yaml service/webapp-service created controlplane ~ ✗ ``` After creating the service, accessing the web application UI should work as expected. *** ## Imperative Commands for Creating Services In the subsequent sections, we will discuss additional imperative commands for creating services. Below are some sample commands that you might find useful for quickly generating service definitions: ```bash theme={null} kubectl expose pod redis --port=6379 --name=redis-service --dry-run=client -o yaml ``` ```bash theme={null} kubectl create service clustertip redis --tcp=6379:6379 --dry-run=client -o yaml ``` ```bash theme={null} kubectl expose pod nginx --type=NodePort --port=80 --name=nginx-service --dry-run=client -o yaml ``` ```bash theme={null} kubectl create service nodeport nginx --tcp=80:30080 ``` *** This concludes the lab for this lesson. In upcoming lessons, we will dive deeper into imperative commands and additional details on managing Kubernetes services effectively. For further reading, check out these resources: * [Kubernetes Basics](https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/) * [Kubernetes Documentation](https://kubernetes.io/docs/) * [Docker Hub](https://hub.docker.com/) * [Terraform Registry](https://registry.terraform.io/)