Intro to Docker Containers – live blog at Oracle Code

Title: Intro to Docker Containers
Speakers: Mike Raab

See my live blog table of contents from Oracle Cloud

 

History of containers

  • ex: UNIX containers, Solairs Zones, VMWare
  • Docker as a product and company made containerization easy

Use cases

  • Ready to run application stacks – setting up a cluster can take a few days even if know what doing. Preparing Docker takes a few minutes once you have it configured.
  • New development/microservices
  • One time run jobs – the data dies with the container by default so good if don’t need it.
  • Front end app servers
  • Server density – Portable – can run same container anywhere

Architecture/Nomenclature

  • VM has entire OS, app, dependencies, binaries, etc.. Container include the app and dependencies.
  • Docker client – CLI for interfacing with Docker
  • Dockerfile – text file of docker instructions to assemble image
  • Image – hierarchies of files. Input to the docker build command. Collection if files and metadata. Contains layers.
  • Container – running instance of an image using the docker run command.
  • User doesn’t know whether you are using a container. Pure implementation.
  • Registry – image repository. DockerHub is largest repo.
  • Docker engine – container execution and admin. Uses Linux Kernel namespaces so have isolated workspaces. Can do Docker for Windows but different image and not popular. 99.9%+ Linux

Commands inside DockerFile

  • FROM x – the base/parent image
  • COPY x y – copy x to y
  • RUN c – run UNIX command c
  • ENTRYPOINT [“a”] – run command a at startup

Docker commands

  • docker build -t dockerfile . – run in current directory
  • docker tag image user/image
  • docker push username/image
  • docker pull username/image
  • doker run – pull the image and run in container
  • docker logs
  • docker ps  – running docker containers
  • docker ps – a – all docker containers whether running or not
  • docker images – list all images
  • docker rm
  • docker tag
  • docker login – login to registry
  • docker push/pull
  • docker inspect – config metadata
  • docker-compose up -d – run multi container Docker applications

Why docker is hot

  • developers love it
  • fast to spin up environment
  • open source
  • code agility, CI/CD pipeline, devops
  • portability
  • managed kubernetes – running it is hard. use managed/cloud environments – oracle commercial time 🙂

My take

Good intro/review. I’m giving a session right after this one and wanted to get ready. So this was a good session for me. Not brand new content, but still go something out of it.

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