Docker & Kubernetes 101 - Part I

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Rise of a Little Whale

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• by Kevin Lin

This is not a training course, actually you probably won't know how to setup a local Kubernetes cluster Just to share a bit of my own background, 10+ years in Java development, enterprise applicatin development As a project team, every engineer should know the basics of docker/kubernetes Raise interest to inspire some of you to take up trainings Tell the story from a different angle, start with looking back in history first, looking at some core concepts in ...

Move to modern JavaScript development 5 years ago. 
Doesn't know docker/kubernetes at all 1.5 years ago.

Exciting Age for Containerisation

• The world of Cloud Computing is fast evolving in recent years
• Container technology is the future
• Docker and Kubernetes are the driving force
• Microservice architecture become widely accepted
• Thriving ecosystems, active communities, huge developer interests

> Cloud native technologies empower organizations to build and run scalable applications in modern, dynamic environments such as public, private, and hybrid clouds. > Containers, service meshes, microservices, immutable infrastructure, and declarative APIs exemplify this approach. > ...

• - Cloud Native Definition by Cloud Native Computing Foundation

It all started, back in year 2013 ...

Year 2013

• PaaS is the hot topic and just about to take off
• Big players have gone through the conceptualization and user education part
• Cloud Foundry, Pivotal, Red Hat, Heroku...

_

Docker was open sourced

• It took the PaaS industry by storm
• The whole community quick shift behind docker, probably even to its creator's surprise
• What did it do right?

In a chinese saying, this is a strike from a higher dimension

What did Docker do right?

• Docker image
• Build once, Run everywhere
• An application archive including base OS and software dependencies
• Perfect solution for application packaging
• Developer friendly
• Every developer can do DevOps now
• Docker Hub
• npm repo for Docker images

Demo

docker run -it ubuntu

docker run -dp 80:80 gscho/linux_tweet_app

docker run -dp 80:80 dockersamples/101-tutorial

Virtual machine (VM)

runs a full-blown “guest” operating system

with virtual access to host resources through a hypervisor

Container

runs natively on Linux

shares the kernel of the host machine with other containers

Container is a contained Linux process

Implmented using core Linux kernel features

1. Isolation (namespace)
2. Limitation (cgroups)
3. Simulation (fsroot)

Isolation - Linux Namespace

Isolate what the process can see, so it lives in its own world

1. PID Mount Namespace
2. Mount Namespace
3. Network Namespace
4. User Namespace
5. UTS
6. IPC

Engineers at Google started the work on this feature in 2006, and was merged into the Linux kernel in January 2008. _

Limitation - Linux Control Group

Set a limit the resources (CPU, memory, I/O) a process can consume

$ mount -t cgroup
cpuset  on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cpu     on /sys/fs/cgroup/cpu type cgroup (rw,nosuid,nodev,noexec,relatime,cpu)
cpuacct on /sys/fs/cgroup/cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct)
blkio   on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
memory  on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
...

Simulation - rootfs

Build the container image to make it behave like an isolated OS

Note: The Linux kernel of the host never change

1. Mount root folders: /bin，/etc，/proc
2. Sometimes, mount the full OS filesystem, i.e. Ubuntu16.04 ISO
3. Change root to the new process root folder
4. The filesystem changes are applied in layers

docker image inspect ubuntu:latest

Docker Compose

• Allows you to define multi-container applications - or “stacks”
• as groups of interconnected services that share software dependencies
• define them in a central file docker-compose.yml
• And run them and manage the entire lifecycle of your applications.

Docker Swarm

• Enables central cluster management as well as the orchestration of containers
• Master-slave architecture
• At least one manager node and any number of worker nodes
• Swarm manager is responsible for the management of clusters and the delegation of tasks
• Swarm workers take over for the execution

Docker & Kubernetes 101 - Part II

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War on Container Orchestration

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• by Kevin Lin

The Competition quickly turn to Container Orchestration

1. Docker - Open Container Initiative (OCI)
2. Mesos - Apache
3. Kubernetes - Cloud Native Computing Foundation (CNCF)

What exactly is Kubernetes?

Kubernetes is not a better version of Docker

• Container runtime agnostic
• It uses Docker by default
• Provide container orchestration like Docker Compose + Swarm
• And much, much more

Kubernetes is not just open source project

• Successor of Borg & Omega, Google's secret weapon
• Designed to manage large-scale computing cluster,
• That powers Google search, Gmail

> “Operating system support for warehouse-scale computing”. PhD thesis, Chapter 2.

• - Malte Schwarzkopf, University of Cambridge Computer Laboratory, 2015

Docker & Kubernetes 101 - Part III

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Kubernetes - OS for the Cloud

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• by Kevin Lin

Kubernetes Recap

• Everything in Kubernetes are API objects
• Master
• Node
• Pod
• Deployment
• Service
• Secret
• ...

Prerequisite

• Working Dev EKS setup and kubectl cli is required.
• Refer to https://confluence.global.standardchartered.com/display/Frog/Setting+up+Development+Environment+for+EKS+on+Windows.

Deployment with Config Files

Generate Deployment Config File

Kubectl commands can be used to generate yaml files easily.

kubectl create deployment ... --dry-run=client -o yaml
kubectl expose deployment ... --dry-run=client -o yaml

Kube Config Example - Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: wealth-api
  name: wealth-api
  namespace: application
spec:
  replicas: 2
  selector:
    matchLabels:
      app: wealth-api
  template:
    metadata:
      labels:
        app: wealth-api
    spec:
      containers:
      - image: artifactory.global.standardchartered.com/frog/frog-wealth-sg:latest
        imagePullPolicy: Always
        name: frog-wealth-sg
        ports:
        - containerPort: 8080

Kube Config Example - Service

apiVersion: v1
kind: Service
metadata:
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-internal: "true"
  labels:
    app: wealth-api-svc
  name: wealth-api-svc
  namespace: application
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: wealth-api
  type: LoadBalancer
  loadBalancerSourceRanges:
  - "10.0.0.0/8"

Videos

You can add videos to your slides, and control the layout just like you do with images.

Both local files and YouTube links playback.

Control the playback by using:

• [autoplay] to start playing the video straight away
• [loop] to loop the video
• [mute] to mute the video