Post on 11-Jan-2017
Kubernetes 101
What to expect
A Kubernetes primer
Tips, tricks, sweat and bloodreal life experience bringing k8s to produc5on
High-load system
Distributed architecture
Our whole infrastructure is on AWS
Our pain points
Underused machines
Autoscaling would take minutes
Non-athomic provisioning makes it difficult to roll-out upgrades or migrate services
The solu)on: Docker!Perfectly determinis/c, ephemeral, light-
weight
Unfortunately containers are just half
of the equa3on
Real costs will emerge as you try to make containers work
together
Kubernetes
def.
(Opinionated) Orchestra1on framework to organise and deploy container-based
applica1ons
Agnos&c sandbox where you provide the desired state of your
services/apps. Kubernetes aims to take care of everything else
Disclaimer!
From the outside Kubernetes is a black box
But inner mechanisms makes it a complex beast to master
We got the cookies!a.k.a. features
Self-healing servicesHealth checks on your containers,
rescheduling failing jobs
Dynamic scalingEnsure current state and scale your pods (but
it's s4ll on you to scale the nodes)
Networking and rou/ngRoute traffic to your containers
Efficient physical resources usageScheduling containers on physical/vms nodes
according to their effec7ve needs
Enough talking
Crea%ng a clusterMULTIZONE=1 KUBERNETES_PROVIDER=aws \KUBE_AWS_ZONE=eu-west-1b NON_MASQUERADE_CIDR="172.16.0.0/14" \SERVICE_CLUSTER_IP_RANGE="172.16.0.0/16" DNS_SERVER_IP="172.16.0.10" \MASTER_IP_RANGE="172.17.0.0/24" CLUSTER_IP_RANGE="172.18.0.0/16" \MASTER_SIZE=m3.medium NODE_SIZE=m3.medium NUM_NODES=1 \./cluster/kube-up.sh
h"ps://asciinema.org/a/4xnz9hc3lvs6zp3eakrf2qcjn
$ kubectl get nodes
NAME STATUS AGEip-172-20-0-209.eu-west-1.compute.internal Ready 47mip-172-20-0-210.eu-west-1.compute.internal Ready 47mip-172-20-0-211.eu-west-1.compute.internal Ready 47mip-172-20-0-212.eu-west-1.compute.internal Ready 47mip-172-20-0-213.eu-west-1.compute.internal Ready 47m
kubectl is your local CLI command center.
You can issue commands to the cluster either by kubectl or directly calling REST APIs exposed by the master
We got the nodes, we are ready
Our first container on kubernetes!
YAML all the things!
PodsA pod is a group of one or more containers. Pods are the smallest
deployable units that can be created and managed in Kubernetes.
Replica(on ControllersA replica*on controller ensures that a specified number of pod
“replicas” are running at any one *me
DeploymentsPod + Replica-onController
apiVersion: extensions/v1beta1kind: Deploymentmetadata: name: dummy-workerspec: replicas: 1 template: metadata: labels: app: dummy-worker spec: containers: - name: dummy-worker image: jnardiello/forever env: - name: SOME_ENV_VAR value: envvarvalue resources: limits: cpu: "256m" memory: "128Mi" requests: cpu: "5m" memory: "8Mi"
ServicesA Kubernetes Service is an abstrac0on which defines a logical set
of Pods and a policy by which to access them.
kind: Servicemetadata: name: dummy-worker-servicespec: ports: - port: 80· targetPort: 8000 protocol: TCP selector: app: dummy-worker externalIPs: [53.8.3.2]
There are different types of servicesNodePorts, proxied by the master
LoadBalancer, crea'ng an actual ELB on AWS
Ingress [beta] - WARNING, do not use
Deploy the containerh"ps://asciinema.org/a/7c42c8itmyz3982p6fmo9ecvi
Resilient applica,onsh"ps://asciinema.org/a/2bxo51ond7ac4haaguneingmv
Kubernetes is truly amazing(for POCs)
Ba#le-tested clusterA long way before reaching produc4on ready
There will be blood!
Opinionated Logging
Opinionated Monitoring
Master skynet, then implement your own solu4on
Custom metrics-based AutoscalingOpsFactory/Kappa
These topics are for another /me(We should probably do Kubernetes102)