DevOps Classroomnotes 07/Apr/2023

Docker Contd

• Applications bring revenue to enterprises and to run applications we need servers, os etc

Lets create a linux server and install tomcat in it

• Create a linux server (AWS/Azure/GCP)
  
• We have experimented in the linux vm
  • network interface gives network connectivity
  • cpu, ram and disk are available
  • to install softwares we have used package manager apt
• Commands

sudo apt update
sudo apt install net-tools openjdk-11-jdk tomcat9 -y
# to check network
ifconfig
# to check java
java -version
# to check tomcat
sudo systemctl status tomcat9

• We were able to exactly the similar operations inside container as well.

Let me take a application

• This is spring pet clinic application
• Lets try to run this application on linux
• Refer Here
• To build the code

sudo apt update
sudo apt install openjdk-17-jdk maven -y
git clone https://github.com/spring-projects/spring-petclinic.git
cd spring-petclinic
# java package
mvn package
java -jar target/spring-petclinic-3.0.0-SNAPSHOT.jar

• Docker way of working
  • We create a docker image (docker packaging format)
    • We need to create Dockerfile
    • push the image to registry (docker hub)
    • create the container using the image anywhere
• Dockerfile

FROM amazoncorretto:17-alpine-jdk
LABEL author=khaja
ADD target/spring-petclinic-3.0.0-SNAPSHOT.jar /springpetclinic.jar
EXPOSE 8080
CMD ["java", "-jar", "/springpetclinic.jar"]

• Create docker image

docker image build -t spc:1.0 .

• to create container

docker container run -d -P spc:1.0
docker container run -d -P spc:1.0
docker container run -d -P spc:1.0

Next Steps

• How is container able to give ip address/storage/process/cpu/ram etc
• Container architectures (3 versions)
• understanding image and container
• docker container life cycle
• containerization
• networking , storage aspects