Java on Docker
Running Java apps on Docker
@augustojimenez1
Augusto Alonso de Cruz Jimenez
13 de diciembre de 2018
@augustojimenez1
Augusto Alonso de Cruz Jimenez
"First, solve the problem. Then, write the code."
John Johnson
Agenda
- What is Docker?
- What is a container?
- Containers vs VMs
- Docker advantages
- Challeges using containers
- Let's try it
- Docker image
- Dockerfile
- Running the Java App
@augustojimenez1
Augusto Alonso de Cruz Jimenez
What is Docker?
Docker is a tool designed to make it easier to:
- create
- deploy
- run
applications by using containers.
Docker is open source
@augustojimenez1
Augusto Alonso de Cruz Jimenez
What is a container?
- The app, and all the libraries it needs to run, are packaged as one package.
- Not a whole virtual operating system.
- Only ships things that are not already running on the host computer.
- Containers are isolated.
- More efficient in system resource terms.
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Containers vs VMs
Credits: blog.docker.com
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Docker advantages
- It's can be considered a DevOps tool.
- Faster development.
- Thousands of pre-existing images.
- Reduced application size.
- More apps running on the same hardware.
- Well supported.
- Extensive documentation.
- Well used, Docker allows horizontal scalability.
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Challenges using containers
- Since containers are intended to be used for lightweight applications, they are mostly used for microservices
- Security
- Logging
- Monitoring
- Ephimeral state
- Short lifetime
The answer is cloud orchestration tools: Docker Swarm, k8s, Mesosphere.
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Let's try it...
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Images and Dockerfile
- A Docker image is a file, comprised of multiple layers.
- An image is built from the instructions for a complete and executable version of an application
- When the Docker user runs an image, it becomes one or multiple instances of that container.
- Reusing layers saves time.
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Images and Dockerfile...
- Docker builds images by reading instructions from a Dockerfile
- It is a simple text file that contains instructions that can be executed on the command line
Example of an Dockerfile...
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Q&A
@augustojimenez1
Augusto Alonso de Cruz Jimenez
Thank you!!!
@augustojimenez1
Augusto Alonso de Cruz Jimenez