What is Deployment, Service, Secret and ConfigMap in Kubernetes ☸️?

30 May 2020 » kubernetes

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Intend of blog is to explain use of following kubernetes resources using phpMyAdmin application deployment:

  • Deployment
  • Service
  • Secret
  • ConfigMap

Before going deep dive into deployment architecture let’s first understand this concepts.

Deployment

Deployments represent a set of multiple, identical Pods with no unique identities. Learn more here

Service

Services are use to group pods together using labels & selectors. Learn more here

Secret

Secrets are used to store confidential attributes such as password, API key etc. Learn more here

ConfigMap

ConfigMaps are used to store configuration parameters such hostname, port etc. Learn more here

Architecture

Architecture

phpMyAdmin application comprises of two components UI (phpMyAdmin) and database (MySQL).

Prerequisites

  • Clone github repository

    git clone https://github.com/developersthought/kubernetes-essentials.git
    
  • Go to session_1 directory

    cd ./kubernetes-essentials/session_1/
    

Step 1: Create demo namespace

kubectl create namespace demo

Step 2: Set current namespace to demo

kubectl config set-context --current --namespace=demo

Step 3: Create secret db-secret

Store MySQL root password in secret.

kubectl create -f secret.yaml

Step 4: Create configmap db-config

Store host & port in configmap

kubectl create -f configmap.yaml

Step 5: Create deployment for MySQL

kubectl create -f db-deployment.yaml
kubectl get pods --watch

Exit when pod goes into running state

Step 6: Create service for MySQL

Here service type ClusterIP is used so that it is accessible only inside the cluster.

kubectl create -f db-service.yaml

Step 7: Create deployment for phpmyadmin

kubectl create -f phpmyadmin-deployment.yaml
kubectl get pods --watch

Exit when pod goes into running state

Step 8: Create service for phpmyadmin

Here service type NodePort is used so that it is accessible outside the cluster.

kubectl create -f phpmyadmin-service.yaml

Step 9: Browse phpmyadmin application

Go to browser and browse http://IP_ADDRESS:30030. Login with root user & test password. Here IP_ADDRESS is the ip address of virtual machine where kubernetes is running.

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