Docker - Get started - Day 1

Docker Overview


What is Docker platform:


What is Docker Engine
+ A server which is a type of long-running program called a daemon process
+ A rest api which specifies interfaces that programs can use to talk to the daemon and instruct it what to do
+ A command line interface cli (client)

https://docs.docker.com/engine/article-img/engine-components-flow.png

What can I use Docker for
Responsive deployment and scaling:
Running more workload on the same hardware

What is Docker's architecture
https://docs.docker.com/engine/article-img/architecture.svg

the Docker Daemon


The Docker client


Inside Docker
Docker images

Docker container
Networking information
Environemnt variable
+ Isolated and secure application platform
+ Access to resources running in a different host or container
+ Persistent storage or databases
Docker Registries

Docker services
swarm of docker nodes to work together
support swarm in docker 1.12
docker services are the scalability component of Docker

How does a Docker image work ?
using union file system to combine these layers into a single image
transparent overlaid,
replace what layers it updates.

when you build a docker file:
FROM
LABEL
RUN
Add
ENV
CMD
How does a docker registery work ?
docker store:

How does a container work ?
Use host machine linux kernel:
what happen when you run a container ?
1. Pulls the ubuntu image
2. Create a new container
3. Allocates a fielsystem and mounts a read-write layer
3. Allocates a network/bridge interface
4. Sets up an IP address
5. Executes a process that you specify. /bin/bash
6. Captures and provides application output

The underlyting technology
writen in Go

Namespaces
A set of namespace for the container
Namespaces:

The pid namespace:
The net namespace:
the ipc namespace:
the mnt namespace:
the uts namespace:

Control groups:
specifi avaiable memory
Union file systems
Building block of containers
Multiple UnionfS: AUFS, btrfs, vfs, device-mapper
Container format:
libcontainer