Docker Compose allows defining and running multi-container Docker applications. It uses a compose file to configure applications composed of multiple services that use Docker's API to start and stop containers together. Docker Swarm extends Docker's clustering capabilities and schedules containers across multiple Docker hosts. While Docker Compose is for single host deployment, Swarm enables scheduling containers across multiple hosts for scaling and high availability. The session covered Docker Compose configuration, networking, and compared it to Docker Swarm for clustering containers across multiple hosts.

1. Docker Session IV
Docker Compose and Docker Swarm

2. Discussion on
● Docker Compose
● Docker Swarm
● Docker Compose vs Docker Swarm
● Discussion

3. Docker Compose
● What is docker compose?

4. SETUP
● Install docker compose
○ https://docs.docker.com/compose/install
● Write docker compose yml file
○ docker-compose.yml

5. FORMAT
Version: 3.6
services:
<service_name>:
build:
image:
depends_on:
ports:
volumes:

6. VERSION
● 3.0 - 3.6
● 2.0 - 2.3
● 1.0

7. SERVICES
● Name of a containers group
● Once service can have multiple containers

8. BUILD
● Build: <context>
● Eg.
○ build: ./dir

9. BUILD DETAIL
● Build:
○ Context: <dir>
○ Dockerfile: <alternate dockerfile>
● Eg.
○ Build:
■ Context: ./dir
■ Dockerfile: Rails.Dockerfile

10. BUILD SAMPLE
version: '3'
services:
webapp:
build:
context: ./dir
dockerfile: Dockerfile-alternate

11. IMAGE
● Specify the image to start the container from.
● Image: redis

12. GUESS
● What happens if both build and image tag are present?
build: ./dir
image: webapp:tag

13. RESULT
● What happens if both build and image tag are present?
build: ./dir
image: webapp:tag
This results in an image named webapp and tagged tag, built
from ./dir.

14. PORTS
● <host_port>:<container_port>
● Eg.
○ Ports:
■ 8080:80
ports:
- "3000"
- "3000-3005"
- "8000:8000"
- "9090-9091:8080-8081"
- "49100:22"
- "127.0.0.1:8001:8001"
- "127.0.0.1:5000-5010:5000-5010"
- "6060:6060/udp"

15. VOLUMES
● <host_path>:<container_path>
● Eg.
○ Volumes:
■ “/tmp/logs/:/app/logs/”

16. DEPENDS ON
● Runs dependent container first

17. DEPLOY
● Ignore this
deploy:
replicas: 6
restart_policy:
condition: on-failure

18. BUT WHY?
● Docker compose up and run ignore this as well.

19. DOCKER NETWORK
● Network drivers
○ Bridge
○ Host
○ None
○ Macvlan
○ Overlay
○ Network plugins

20. BRIDGE
● Default
○ Created by default
● User defined
○ User needs to create and attach it to container
■ During container run command
■ Attach on running container

21. BRIDGE DIFF
● Default
○ Accessible through ip address
● User defined
○ Accessible through both ip address and container name

22. HOST
● Uses host network

23. NONE
● No communication through network

24. MACVLAN
● Uses mac address

25. OVERLAY
● Uses for multi host containers

26. NETWORK PLUGINS
● Install and use third-party network plugins with Docker

27. COMMUNICATION

28. NETWORK SUMMARY
● User defined bridge network for single host containers
● Overlay for multi host containers communication

29. Docker Swarm
● What is docker swarm?
○ Clustering and
○ Scheduling tool

30. DOCKER COMPOSE vs SWARM
● Single vs Multiple hosts
● Swarm uses overlay network driver

31. UPCOMING
● Who is going to present on what?

32. Queries???

33. Thank You!!!