Kubernetes

The Ruby Way

RubyConf Malaysia 2018

Hello!

Iqbal Farabi

System Engineer

Go-Jek Indonesia

At the end of this talk...

We will have discussed about...

  • Why a tool such Kubernetes is needed?
  • Key concepts of Kubernetes
  • Provisioning Kubernetes cluster with Ruby-based tool
  • Deploying Ruby apps to Kubernetes
  • Sneak peek on Go-Jek's use of Kubernetes

Start with Why

Monolithic architecture is simple to develop, deploy, and scale.

Horizontal Scaling with Monolithic Apps

along came Microservices...

Horizontal Scaling with Microservices

But every new solution introduces new problems...

Dependencies Madness

We Need Isolation

Virtual Machines

We can isolate components using Virtual Machines (VMs). This way, each components can have their own dependencies satisfied without getting in the way of each other.

 

The problem with VM is that it takes a lot of hardware resources, therefore not ideal for microservice-based app with large number of services.

Virtual Machines

Containers

Containers run as isolated process on host OS instead of running its own guest OS. This is achieved by using Linux namespaces, cgroup, and chroot*.

 

That way, containers provide isolation without consuming as much resources as VMs. With the same specs, a bare-metal host can run more containers than VMs.

 

* checkout: Building Containers from Scratch

Containers

VMs and Containers

Kubernetes

Greek for pilot, helmsman, governor.

In a brief...

Kubernetes is a software system that allows you to deploy and manage containerized applications on top of it.

 

Kubernetes enables you to run your software applications on multiple distributed nodes as if all those nodes were a single, enormous resource.

 

Kubernetes can be thought of as an operating system for the cluster.

In a picture...

In an official diagram...

In action...

Provisioning

Kubernetes Cluster 

The Hard Way

Things You Need to Setup

Provision:

  • Compute resources
  • Certificate authority
  • Kubernetes Configuration files
  • Data encryption keys
  • Etcd cluster
  • Kubernetes controllers
  • Kubernetes workers
  • Configuring kubectl
  • Network routes and DNS add-on

Visit this page.

The Ruby Way

1 - Puppet Server Instance

gcloud compute instances create istabon --zone asia-east1-a --machine-type n1-standard-1 \
  --image ubuntu-1604-xenial-v20181023 --image-project ubuntu-os-cloud

Create a GCP  compute instance.

Prepare necessary credentials. These steps will asume you have a service account and it is saved as file named 'gcp-auth.json' and project named 'qblfrb=kubernetes-lab'.

gcloud compute ssh istabon

gcloud compute scp gcp-auth.json istabon:~/gcp-auth.json --zone asia-east1-a

gcloud auth activate-service-account --key-file=gcp-auth.json --project=qblfrb-kubernetes-lab

2 - Install Necessary Tools

wget https://apt.puppetlabs.com/puppetlabs-release-pc1-xenial.deb
sudo dpkg -i puppetlabs-release-pc1-xenial.deb
sudo apt-get update
sudo apt-get install puppetserver

Install 'puppetserver'.

Install 'googleauth' and 'google-api-client'

sudo /opt/puppetlabs/puppet/bin/gem install googleauth -v 0.6.7
sudo /opt/puppetlabs/puppet/bin/gem install google-api-client --no-ri --no-rdoc

3 - Provision GCE

/opt/puppetlabs/puppet/bin/puppet module install google/cloud

Install Puppet module for Google cloud.

Write the following manifest, for instance 'gcontainer_cluster.pp'.

gauth_credential { 'gauth-credential':
  provider => serviceaccount,
  path     => '/home/iqbalfarabi/gcp-auth.json',
  scopes   => ['https://www.googleapis.com/auth/cloud-platform'],
}

gcontainer_cluster { 'istabon':
  ensure             => present,
  initial_node_count => 2,
  node_config        => {
    machine_type => 'n1-standard-4',
    disk_size_gb => 500,
  },
  credential         => 'gauth-credential',
  zone               => 'asia-east1-a',
  project            => 'qblfrb-kubernetes-lab',
}

/opt/puppetlabs/puppet/bin/puppet apply gcontainer_cluster.pp

Apply it.

4 - Validate The Cluster

gcloud container clusters get-credentials istabon

Get cluster credential.

Validate nodes and kube-system pods exist.

kubectl get nodes
kubectl get pods -n kube-system

Your cluster is up and running!

Also see..

Interesting Ruby-based Kubernetes tools you might want to look at:

  • https://github.com/puppetlabs/kream
  • https://forge.puppet.com/garethr/kubernetes

Deploying a Ruby App

to Kubernetes

1 - A Simple Sinatra App

require 'sinatra'

enable :run, :show_exceptions

set :environment, :production
set :bind, '0.0.0.0'
set :port, 80

get '/' do
  'Hello, world!'
end

Hello world:

2 - Container Image

FROM ruby:2.5.1

RUN gem install sinatra

WORKDIR /usr/src/app
COPY hello-world.rb .

EXPOSE 80

CMD /usr/local/bin/ruby ./hello-world.rb

Write a Dockerfile:

Build and push to Dockerhub:

docker build -t qblfrb/hello-world-sinatra:0.1.0 .
docker push qblfrb/hello-world-sinatra:0.1.0

3 - Kubernetes Manifest (1)

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sinatra
spec:
  selector:
    matchLabels:
      app: sinatra
  replicas: 1
  template:
    metadata:
      labels:
        app: sinatra
    spec:
      containers:
        - name: sinatra
          image: qblfrb/hello-world-sinatra:0.1.0
          ports:
            - containerPort: 30080

Deployment:

3 - Kubernetes Manifest (2)

apiVersion: v1
kind: Service
metadata:
  name: sinatra
  labels:
    app: sinatra
spec:
  type: NodePort
  ports:
    - port: 80
      nodePort: 30080
      protocol: TCP
      name: http
  selector:
    app: sinatra

Service:

4 - Run

kubectl apply -f sinatra.yaml

Apply:

kubectl get pods -l app=sinatra
kubectl port-forward sinatra-788f79cff4-fpqxw 8080:80

Port-forward:

Kubernetes in Go-Jek

Multiple Approaches

+

=

+

=

+

Kubeadm

=

The Bootstrapper

The Bootstrapper is a tool that we created to empower developers in managing their own Kubernetes cluster on AWS. This is only one of many Kubernetes related tools we have in Go-Jek.

 

We implement the reconciler pattern as described in Kris Nova's book Cloud Native Infrastructure. We utilize Terraform and Kops to automate cluster creation, update, and deletion.

Simple things should be simple, complex things should be possible.

- Alan Kay

cluster_name: istabon.sample-cluster.io
vpc_name: istabon-staging
nodes:
  count: 4
  size: m5.4xlarge
masters:
  count: 3
  size: m4.2xlarge
zones:
  - ap-southeast-1a
  - ap-southeast-1b
  - ap-southeast-1c
subnets:
  - cidr: 10.14.14.0/24
  - cidr: 10.14.15.0/24
  - cidr: 10.14.16.0/24
utility_subnets:
  - cidr: 10.14.17.0/28
  - cidr: 10.14.17.16/28
  - cidr: 10.14.17.32/28
topology: private
bucket_region: ap-southeast-1
├── cluster-definition
│   ├── istabon.sample-cluster.io
│   │   └── config.yaml
├── kops
│   ├── istabon.sample-cluster.io
│   │   ├── alertmanager.yaml
│   │   ├── cluster.yaml
│   │   ├── gcr-secret.yaml
│   │   ├── grafana-service.yaml
│   │   ├── instance-group-bastions.yaml
│   │   ├── instance-group-master-1.yaml
│   │   ├── instance-group-master-2.yaml
│   │   ├── instance-group-master-3.yaml
│   │   ├── instance-group-nodes.yaml
│   │   ├── kops-secret.yaml
│   │   ├── kubectl-proxy-secret.yaml
│   │   ├── prometheus-custom-rules.yaml
│   │   ├── prometheus-service.yaml
│   │   └── tiller-rbac-config.yaml
├── scripts
└── terraform
    └── istabon.sample-cluster.io
        └── services
            └── kops-setup
                ├── backend.tf
                ├── data.tf
                ├── main.tf
                ├── output.tf
                ├── provider.tf
                └── var.tf

Cluster with Benefits

Benefits (1)

Faster Setup Time

Setting up the whole Go-Viet infrastructure only took four days.

 

Cookie Cutter Model

Repeatable/immutable nature of containerizing helps us to replicate our MVP launch strategy for different geographies.

 

Scalable

Scaling based on business growth is very easy.

Benefits (2)

Faster MTTR

In the case of traffic spike, for instance, we can spin up new containers much more quickly than setting up new VMs.

 

Higher Uptime

High availability setup lead to fewer outage.

 

Efficiency

System resources like CPU, memory, etc. are more effectively utilized in container world than in VMs.

Benefits (3)

Easy Configuration

Automatic service discovery allows engineers to not maintain any configuration for multi-data center deployments.

 

Cost Effective

Save > 60% cost compared to VM per year per country for international expansion projects.

References

and Reading Materials

  • Kubernetes in Action – Mario Luksa

  • Kubernetes: Up and Running – Joe Beda, Brendan Burns, Kelsey Hightower

  • Cloud Native Infrastructure – Kris Nova, Justin Garrison

  • Building Microservices – Sam Newman

  • Designing Distributed System – Brendan Burns

  • Giri Kuncoro

  • Vijay Dhama

  • Himani Agrawal

  • Prashant Mittal

  • Irfan Shah

  • Sumit Gupta

  • Willem Pienaar

  • Arief Hermansyah

  • Shani Pribadi

  • Sourabh Gupta

Thank You!

Kubernetes The Ruby Way

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