Docker Notes

Docker Notes
---
docker daemon 
REST Api to interact with it
CLI to interact with it uses the REST APIs

your docker daemon can run on a totally different machine and you can issue commands to it from your local

'dockerd' = daemon
'docker' = using the api

Images
---
r/o with instructions for creating container
an image can be based on another image

instructions create layers in the image

images can be parent child relationships

Containers
---
runnable instance of image
docker run -i -t ubuntu /bin/bash
^ run ubuntu image in a container and run the /bin/bash

Services
---
allow you to scale across multiple daemons (possibly on other machines) <-- swarm
You can have a swarm which is a grouping of containers. This grouping is orchestrated by a single daemon that manages the swarm. 
By default, the service is load-balanced across all worker nodes

dependencies, app config, etc bundled into image. Quick redeploys using new images. 

Phases - build, ship, run

Solves the "Works on My Machine" phenomenon

Syntax
---
FROM = base image
FROM node:12.16.3

WORKDIR
WORKDIR /code
^ creates dir and uses as working

ENV
ENV PORT 80
^ set environment variable

COPY
COPY package.json /code/package.json
^ copy to dir

RUN
RUN npm install

CMD 
CMD ["node", "src/server.js"]
^ tells docker run command and target

.dockerignore -> tell docker to not copy over these files/directories

Building
---
docker build --tag hello-world .

docker images
^ see installed images

Running
---
docker run [image]
^ you can specify a ton of things like memor, cpu, io, network

docker ps -a shows you non running images
docker ps shows you running images
docker rm [gets rid of images]
if you dont specify a name, docker will you you some wacky one

docker run -p 8080:80 --name hello -d hello-world

-p maps local port 8080 to container port 80
-d allows for detached mode


*** docker system prune *** to get rid of old non-running images

docker stop

docker logs -f [container] 

docker hub for private images

can connect to docker hub image to get rebuilt on git commit

docker tag hello-world dg/hello-world

if you want to push to hub, your images namespace must match the namespace as hub

Docker Compose
---
allows you to specify yaml files that define the run specification (can be 1 or more services)

docker-compose up -d

up means run but for all services in the compose


Open Questions
---
1) Where do we specify the resources of the container? --> Run Command
2) Branches of images? --> Done by Tagging


Notes
---
Good tutorial - https://www.youtube.com/watch?v=iqqDU2crIEQ














Docker Notes
---
docker daemon 
REST Api to interact with it
CLI to interact with it uses the REST APIs

your docker daemon can run on a totally different machine and you can issue commands to it from your local

'dockerd' = daemon
'docker' = using the api

Images
---
r/o with instructions for creating container
an image can be based on another image

instructions create layers in the image

images can be parent child relationships

Containers
---
runnable instance of image
docker run -i -t ubuntu /bin/bash
^ run ubuntu image in a container and run the /bin/bash

Services
---
allow you to scale across multiple daemons (possibly on other machines) <-- swarm
You can have a swarm which is a grouping of containers. This grouping is orchestrated by a single daemon that manages the swarm. 
By default, the service is load-balanced across all worker nodes

dependencies, app config, etc bundled into image. Quick redeploys using new images. 

Phases - build, ship, run

Solves the "Works on My Machine" phenomenon

Syntax
---
FROM = base image
FROM node:12.16.3

WORKDIR
WORKDIR /code
^ creates dir and uses as working

ENV
ENV PORT 80
^ set environment variable

COPY
COPY package.json /code/package.json
^ copy to dir

RUN
RUN npm install

CMD 
CMD ["node", "src/server.js"]
^ tells docker run command and target

.dockerignore -> tell docker to not copy over these files/directories

Building
---
docker build --tag hello-world .

docker images
^ see installed images

Running
---
docker run [image]
^ you can specify a ton of things like memor, cpu, io, network

docker ps -a shows you non running images
docker ps shows you running images
docker rm [gets rid of images]
if you dont specify a name, docker will you you some wacky one

docker run -p 8080:80 --name hello -d hello-world

-p maps local port 8080 to container port 80
-d allows for detached mode


*** docker system prune *** to get rid of old non-running images

docker stop

docker logs -f [container] 

docker hub for private images

can connect to docker hub image to get rebuilt on git commit

docker tag hello-world dg/hello-world

if you want to push to hub, your images namespace must match the namespace as hub

Docker Compose
---
allows you to specify yaml files that define the run specification (can be 1 or more services)

docker-compose up -d

up means run but for all services in the compose


Open Questions
---
1) Where do we specify the resources of the container? --> Run Command
2) Branches of images? --> Done by Tagging


Notes
---
Good tutorial - https://www.youtube.com/watch?v=iqqDU2crIEQ