Images:

Docker images are template that define the container and its dependencies

Containers

Containers are runtime environments created from docker images

Docker Engine

The docker engine is the runtime that runs and manages containers

Dockerfile

A dockerfile is a file that contains instructions to build a docker image

Command to create a docker image

./mvnw spring-boot:build-image "-Dspring-boot.build-image.imageName=georgekibe/jobapplicationwebsiteimage"

Push image to docker hub

docker push georgekibe/jobapplicationwebsiteimage

Useful docker commands

• Pull Image docker pull <image>
• Push Image docker push <username/image>
• Run a docker container from image. i for interactive mode. d for detach mode which allows running other commands in terminal. p allows port mapping.docker run -it -d -p <host-port>:<container-port> <container-name>
• Stop container docker stop <container>
• Start a container docker start <container>
• Delete a stopped container docker rm <container-id/container-name>
• Remove an image from localstoarge docker rmi <image-id/image-name>
• Get all running containers docker ps
• Get all conatiners docker ps a
• List all images on host docker images
• Access a running container docker exec -t <container-name/container-id> bash
• Build a docker imager docker build -t <username/image>
• Get logs of a runing container docker logs <container-name/container-id>
• Get information of a particular container docker inspect <container-name/container-id>

Working with docker, Java and Postgresql

A summary of commands to use in setting up docker running java spring boot application to run with postgres database

• Installing Postgres Image and setting password to use. -e allows to set environmental variables. docker run -d --name db -e POSTGRES_PASSWORD=password postgres
• Adding PgAdmin docker run -d --name pgadmin -e PGADMIN_DEFAULT_EMAIL=admin@admin.com -e PGADMIN_DEFAULT_PASSWORD=password dpage/pgadmin4
• Exec allows to execute commands in a docker container. it allows use of an interactive console. Ping is used to check reachability/connectivity of a network. docker exec -it pgadmin ping db
• docker rm -f db pgadmin Using Networks
• Create a network docker network create my-network
• Rerunning the postgres docker image associating it to created network. docker run -d --name db --network my-network -e POSTGRES_PASSWORD=password postgres
• Rerunning the pgadmin docker image associating it to created network. docker run -d --name pgadmin --network my-network -e PGADMIN_DEFAULT_EMAIL=admin@admin.com -e PGADMIN_DEFAULT_PASSWORD=password dpage/pgadmin4
• Rerun the ping command to check connectivity. docker exec -it pgadmin ping db

RabbitMQ configurations- Running from docker

  rabbitmq:
    image: rabbitmq:3-management
    container_name: rabbitmq
    ports: 
      - 5672:5672
      - 15672:15672
    networks:
      - postgres

Running from the terminal

docker run -d --name rabbitmq -p 5672:5672 -p 15672:15672 rabbitmq:3-management

Packaging commands

1. To package using maven ./mvnw package or ./mvnw clean package
2. To verify jar file jar -tf target/companyMs-0.0.1-SNAPSHOT.jar
3. To run the jar file java -jar companyMs-0.0.1-SNAPSHOT.jar

Building individual images for all microservices

Navigate to each of the folders and run ./mvnw spring-boot:build-image "-Dspring-boot.build-image.imageName=georgekibe/servicereg" Docker push to your account Format is docker push georgekibe/ docker push georgekibe/jobapplicationwebsiteimage

Working with kubernetes and minikube

launch minikube dashboard minikube dashboard Creating a pod kubectl apply -f first-pod.yml Viewing all pods kubectl get pods View Everything kubectl get all Creating a service kubectl apply -f first-service.yml Viewing all services kubectl get service or kubectl get services

Deleting all deployments kubectl delete deployments --all --all-namespaces

Delete all the services kubectl delete services --all --all-namespaces

Delete all Pods kubectl delete pods --all --all-namespaces

Delete all replicasets kubectl delete replicasets --all --all-namespaces

Using Postgres on Kubernetes kubectl exec -it postgres-0 -- psql -U george