Docker can be used to build, test, and deploy software applications. It allows creating software containers that package code and dependencies together. Docker is useful for testing applications in isolation, continuous integration testing, and distributing software. Some key benefits are portability across stacks, reusable images, and treating infrastructure as code. Challenges include evolving standards and ensuring version compatibility across images and tools.

1. Docker: Build, test and deploy
SaaS applications
William Greenly, Technology and Platform Manager Jio XLabs
Jio

2. Jio
● It is the largest 4G network in the world, and by 2019 it will be available for over 1
billion Indians across the entire country, urban and remote rural. Most users
experience between 18-70 Mbs download speeds.
● It is entirely IP based. No separate analogue/hybrid network for voice.
● It is launching with 1 tariff and 1 tariff only - data.
● Which it will charge at a maximum of 50 rupees per GB making it the cheapest in
the world.
● It is completely free for anyone and everyone who signs up, until December 31st
2016.
● After thursday's announcement it wiped 9% off the competitions market value.

3. Meetup Groups
● Extreme Engineering
● Web of Things

4. Introduction to Linux Containers
● LXC has been around for nearly 10 years
● Namespaced virtual machines than run in the kernel
● Isolation, container grouping, networking, process mgts, security, storage
● Ephemerality
● Standardisation still lacking

5. What is Docker (and it’s ecosystems)
● A system for managing Linux Containers
○ Docker Engine
● A system for creating Linux Images
○ Dockerfile
● An ecosystem for sharing and reusing Linux Images
○ Docker Registry, Docker Hub
● An ecosystem for orchestrating and linking containers
○ Docker Compose
● An ecosystem for running distributed containers
○ Docker Swarm + Docker Compose (Kubernetes, Rancher, ECS, Bluemix)

6. Some key use cases
● Localised end to end testing
● End to end testing during continuous integration
● Emulators for tricky 3rd party services
● Technology agnostic substitute for the test harnesses
● Building and deploying software distributions
● Building and deploying end to end, HA, SaaS products

7. Testing
● Integrates with existing build tools
● Use docker for difficult to test or remote 3rd party services
○ E.g Amazon S3, Tibco, Oracle etc
● Reduces the amount of time building test harnesses
● End to end testing locally, against real services
● Agnostic images means better reuse across technology stacks (e.g Ruby, Java,
Python)
● Still versionable

8. As a software distribution
● Applications can be distributed as images with OS level dependencies included
● Enabling more portable software
● 12 Factor App - Configuration can be part of the environment
● Again Versionable
● Pushed and pulled to a repository e.g Docker Registry, Docker Hub, Bintray etc. etc

9. Docker in production
● Docker compose
○ Orchestration, hostnames and dns, scaling on Swarm
○ Gradle, Grunt, Rake, docker-compose.yml, Bash, Docker Swarm
● Kubernetes
○ Orchestration, service discovery (pretty poor), replication controllers and load balancing (not DNS),
health checks and monitoring, deployments
○ Gradle, Kubernetes.yml, Bash/Ansible GCE
● Ansible
○ Playbooks, ECS
● Chef, Puppet
● Deployment and delivery pipelines, blue/green, red/black, canary, immutable

10. Gotchas
● Docker is still a rapidly evolving ecosystem. Lots of version compatibility issues.
● Versioning is very relaxed. Can lead to Snapshot abuse and untested dependencies
ending up in production.
● Better resource utilisation than Hypervisors, but still needs to be managed
● Volumes and persistence
● Large images - look to optimised distributions