DevOps Classroom Series – 02/Sept/2021

Docker image building

• Manual Steps:
  • Ensure python is installed
  • Ensure pip is installed
  • clone the code from github git clone https://github.com/khajasampleapps/basicflask.git
  • Execute pip install -r requirements.txt
  • To run your application python app.py
• Refer Here for the Dockerfile
• Now if we want to make this image available to others, we need to push the image to the registry.
• Generally the format for registry is <username>/<image>:<tag>
• DockerHub:
  • This is a public registry and also it has private registry option
  • Execute the command docker login
  • Now push the tagged image
  • Now any one can run this flask application

  docker container run -d -P shaikkhajaibrahim/flaskdemo:1.0.0
  

• Other Registries
  • AWS ECR: This supports public and private registries hosted on AWS.
    • To work with this install AWS CLI Refer Here
  • Azure Container Registry: This is registry hosted on azure Refer Here
    • Install Azure Cli Refer Here
  • Artifactory/jfrog: Refer Here

Multi Staged Builds

• Overview:
• Lets try to build the springpetclinic
• Manual steps:
  • this needs jdk 11
  • We need maven

  git clone https://github.com/spring-projects/spring-petclinic.git
  cd spring-petclinic
  mvn package
  # this generates the jar file
  

• Dockerfile with multistaged build

FROM maven:3-openjdk-11 AS builder
RUN git clone https://github.com/spring-projects/spring-petclinic.git \
    && cd spring-petclinic \
    && mvn package


FROM openjdk:11
LABEL author="khaja"
EXPOSE 8080
COPY --from=builder /spring-petclinic/target/spring-petclinic-2.5.0-SNAPSHOT.jar /spring-petclinic.jar
CMD ["java", "-jar", "/spring-petclinic.jar"]

• Lets try to build the gameoflife
• Manual steps:
  • This requires jdk 8

  git clone https://github.com/wakaleo/game-of-life.git
  cd game-of-life
  mvn package
  

• Exercise: Create a mutlistage build for gameoflife and springpetclinic and push the image to docker hub and any private registry.