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Cover image for What is Deployment, Service, Secret and ConfigMap in Kubernetes?
Sagar Jadhav
Sagar Jadhav

Posted on • Originally published at developersthought.in

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

#kubernetes #devops #beginners #opensource

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

Alt Text

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

Prerequisites:

Clone github repository 

git clone https://github.com/sagar-jadhav/kubernetes-essentials.git
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Go to session_1 directory 

cd ./kubernetes-essentials/session_1/
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Step 1: Create demo namespace 

kubectl create namespace demo
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Step 2: Set current namespace to demo 

kubectl config set-context --current --namespace=demo
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Step 3: Create secret db-secret

Store MySQL root password in secret.

kubectl create -f secret.yaml
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Step 4: Create configmap db-config

Store host & port in configmap

kubectl create -f configmap.yaml
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Step 5: Create deployment for MySQL 

kubectl create -f db-deployment.yaml
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kubectl get pods --watch
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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
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Step 7: Create deployment for phpmyadmin 

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

Demo

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