Docker allows for the delivery of applications using containers. Containers are lightweight and allow for multiple applications to run on the same host, unlike virtual machines which each require their own operating system. Docker images contain the contents and configuration needed to run an application. Images are built from manifests and layers of content and configuration are added. Running containers from images allows applications to be easily delivered and run. Containers can be connected to volumes to preserve data when the container is deleted. Docker networking allows containers to communicate and ports can be exposed to the host.

1. Docker &
docker run vishnu

2. What is Docker ?

3. What is Docker ?
It’s a Application Delivery Technology.

4. Terminology Briefing
● Docker or Docker Engine
● Docker Host
● Docker Daemon
● Docker Container

5. Qns:
Docker Container = VM ?

6. Qns:
Docker Container = VM ?
Ans: NO

7. House Apartment ’s

8. 1 - Virtual Machine Many Containers

9. Motivation
● Isolation
● Lightweight when compared to VM
○ Multiple docker containers share the underlying
resources of the docker host.

11. Terminology Briefing
● Docker Image
● Docker Container

12. Biggest Motivation:
Its an Application Delivery Mechanism !

13. Qns:
How do we deliver our Apps ?

14. Qns:
How do we deliver our Apps ?
Ans:
In docker terms, we create and ship
DOCKER - IMAGE

15. This is an open Container

16. This a Manifest for the open container.

17. The Cargo for your container
Obviously you
declare all this
in the manifest !

18. Close it , i.e build it - and you have an image.

19. My Analogy
● Open Container = Docker build directory
● Container Manifest = Docker build File
● The Cargo = The necessary things to run your App
● Properly Closed Container = Properly Built Image

20. Concept of layers in an Image
Each Box of cargo you add forms a LAYER in an image.
You can add a new LAYER on TOP of the previous layer.
Hint :- stack of pancakes

24. Docker build -t Manifest.dockerfile

25. IMAGE now built and ready to be shipped.

26. Shipping = pushing image to Docker
Registry

29. Now that the Closed Container
(IMAGE)
is available,
What next ?

30. Next : Running Multiple containers
On ONE Host

31. Cargo ship (Docker Host) running many containers ...

32. NOTE:
Ships only move in the sea
So do containers.

34. Life of a container
While running container, it may create new resources like log
files , database files etc.

35. Life of a container
While running container, it may create new resources like log
files , database files etc.
Once we destroy a container, we LOSE everything.

36. Life of a container - how to preserve its state ?
So, one can choose to MOUNT directories into the container .

37. Life of a container - how to preserve its state ?
So, one can choose to MOUNT directories into the container.
The container can write to the mounted dir and when the
container is destroyed, its state is preserved in the mount.
We call them docker volumes

38. Docker Container - Networking ?
Can i access all the ports of the container ?

39. Docker Container - Networking ?
Can i access all the ports of the container ?
-> By Default No, you need to explicity expose them.

40. Docker Container - Networking ?
Can i access all the ports of the container ?
-> By Default No, you need to explicitly expose PORTS.
Does it have an ip address ?
-> it does a have private IP.

42. More reading ...
https://docs.docker.com/engine/understanding-docker/
https://blog.docker.com/2016/03/containers-are-not-vms/
+ Internet ….

43. Docker thank you
sweetweet213
Jaihind213