Docker Notes

A Brief History Of The Shipping Industry (DOCKER)

loading and unloading of goods in barrel, sacks and wooden crate from land transporters to ship and back again on arrival.
this process: break-bulk shipping was the only known way to transport goods until the 20th century. slow and cumbersome.
then came dockers

What problem docker is solving?

Keep Your Computers Tidy with Containers (locally)
When someone sends you a Java App, is the JVM installed? What about runtime libraries? What about additional libraries? Where does the App Begin and End? Docker solved for answering that question predictably, accurately, portably and conclusively. [ref taken]
run a piece of software in isolation from the rest of the system (making clean everything)
kind of resembles to python virtual environments

VM and Container

Similar to a VM, a container has its own filesystem, CPU, memory, process space, and more.

Benefits of Container

increased ease and efficiency of container image creation compared to VM image use.
Dev and Ops separation of concerns
Environmental consistency across development, testing, and production: Runs the same on a laptop as it does in the cloud.

Docker Compose vs. Dockerfile

docker-compose	dockerfile
- compose whole application services	- used for single service
- docker-compose.yml	- Dockerfile
- deploy entire stack with docker compose command	- create useful containers (might be reusable)

Dockerfile
- create dockerfile to build images
Docker Compose
- used for defining and running multi-container Docker applications

Which one to use? Best of two worlds...

make use of both dockerfile and docker-compose

docker container vs image

Running instance of an image = contianer

Docker run with flask app

running from dockerfile

first build an image with -t tag and then only run
couldn’t found the way to run from Dockerfile directly, first need to build and then run the image as a container

Networking using the Host Network

The host networking driver only works on Linux hosts, and is,
not supported on Docker Desktop for Mac, Docker Desktop for Windows, or Docker EE for Windows Server.

Docker Dev

running mysql dev locally.
// goto local docker compose

$ docker-compose up -d detach the container

$ docker exec -it mysql-dev /bin/bash run shell on mysql-dev

$ docker exec -it c0f6543a8f36 /bin/sh -c "printenv" run particular command

Docker Engines

Docker Engine Swarm Mode (Kubernetes alternative by Docker)
- cluster of docker engines
- addings nodes to the swarm
- deploying application services to the swarm
- managing the swarm after everything is running
Docker Desktop for Mac
- You can test both single-node and multi-node swarm from this computer, but you need to use
- Docker Machine to test the multi-node scenarios.

Docker Network

$ docker network create -d bridge mynet

creating a docker network

Kubernetes

The technical definition of orchestration is execution of a defined workflow: first do A, then B, then C.

Docker Compose

write docker-compose.yml
$ docker-compose up
volumes:
- Mounting volumes enables us to map local source code to the corresponding code in the container, so that every time we edit these code files in our local the changes will be instantly reflected in the container.
Docker compose what is link?

docker-compose commands

$ docker-compose up -d detach docker compose

$ docker-compose ps docker-compose processes

$ docker-compose stop stop the services

Dockerfile run / cmd / entry point?

| RUN | CMD | ENTRY POINT | |———————————————————————————|———————————————————-|————-| | when running the commands for creating the layer in the docker: use run command | runs each and everytime when docker container is running | - | |||

script - entry point how to run?

docker mysql local dev

$ docker run -p 3304:3306 --name mysql-local -e MYSQL_ROOT_PASSWORD=toor -d mysql:latest