Kubernetes and devops

Kubernetes and DevOps
資訊與通訊研究所蔣是⽂文 Mac Chiang

Copyright 2017 ITRI ⼯工業技術研究院
Agenda
• Kubernetes Introduction
• Scaling and Upgrading with K8S
• Hands ON (Demo)
• Q & A
2

OpenStack Summit 2017 
Will Kubernetes Steal the Show?
• Before the summit:
▪ OpenStack on Kubernetes?
▪ Kubernetes on OpenStack?
▪ How about Kubernetes on OpenStack on Kubernetes?
• The list of breakaway sessions
▪ Kubernetes and OpenStack at Scale.
▪ OpenDaylight Kubernetes & OpenStack Magnum integration.
▪ ESCaaS 4.0, Unified Management Platform of OpenStack and Kubernetes.
▪ Hybrid Cloud Kubernetes.
▪ Hybrid Orchestration: Kubernetes on Bare Metal and OpenStack Demo.
▪ Panel: Enterprise Adoption of Kubernetes and Containers.
https://thenewstack.io/openstack-summit-2017-will-kubernetes-stealing-show/
3

What’s Kubernetes
• “Kubernetes” is Greek for captain or pilot
• Experiences from Google and design by Goolge
• Kubernetes is a production-grade, open-source platform that
orchestrates the placement (scheduling) and execution of
application containers within and across computer clusters.
• Masters manage the cluster and the nodes are used to host the
running applications.
4

Why Kubernetes
5
• Automatic binpacking
• Horizontal scaling
• Automated rollouts and rollback
• Service monitoring
• Self-healing
• Service discovery and load balancing
• 100% Open source, written in Go

Who use Kubernetes
6

Kubernetes 1.6 Scalability Update
5,000 node and 150,000 pod clusters
7

Kubernetes 1.6 Scalability Update (cont.)
API response latency for a
5000-node Kubernetes 1.6
cluster are less than 500ms,
and even 90th percentile is
less than about 100ms
8

Kubernetes Architecture
9

Kubernetes Architecture (cont.)
10

Kubernetes Architecture (cont.)
11

etcd
• Distributed key, value store
• Used for configuration and monitoring store
• Used for Service discovery
• JSON/REST API
12

flannel
• A virtual network that
gives a subnet to
each host for use with
container runtimes
13

The Key Concept
• Pod
• Smallest deployable unit
• Shared context
• Service
• Targets pods
• Long-lived
• Deployment (Replication
controller)
• Ensure N pods are running
• Pod template
• Label
• Key/value pair
• Organize, select objects
• Kubernetes
14

Nodes
• A node is a worker machine in
Kubernetes and may be a VM
or physical machine
• Multiple Pods can run on one
Node
15

Pods
• A group of one or more containers
• Containers within a pod share IP, port, namespaces and
volumes.
16

Service
• Persistent
• Routes traffic across a set of
Pods
• Provide load balancer
• Provide discovery
• Provide stable service address
• Find pods by label selector
A Service is an abstraction
which defines a logical set of
Pods and a policy by which to
access them
17

Label
• Metadata with semantic
meaning
• Label selector
• Set of objects
18

Namespace
• Group + segment pods, rcs, volumes and secrets from each other
https://www.slideshare.net/imesh/multitenancy-in-c5
19

Deployment (Replication Controller)
• Provides declarative updates for Pods and ReplicaSets
• Rollout/ Roll back a ReplicaSet
• Scale up the deployment
20

Deployment
Deployment
Replica Set
Replica Set
Replica Set Replica Set
Pod Pod
Pod Pod Recommend using
Deployments instead of
directly using
ReplicaSets
21

Deployment (cont.)
• A Deployment provides declarative updates
for Pods and ReplicaSets
• Typical use case
▪ Create a Deployment to rollout a ReplicaSet
▪ Rollback to an earlier Deployment revision
▪ Scale up the Deployment to facilitate more load
▪ Use the status of the Deployment as an indicator that a rollout has stuck
▪ Clean up older ReplicaSets that you don’t need anymore
22

Scaling
Scaling is accomplished
by changing the number
of replicas in a
Deployment
23

Scaling (cont.)
24

Horizontal Pod Autoscaling
• Automatically scales the number
of pods in a replication controller,
deployment or replica set based
on observed CPU utilization
• Operates within user-defined min/
max bounds
• Set it and forget it
https://www.slideshare.net/DanielSmith272/whats-new-in-kubernetes
25

Canary Deployment
https://martinfowler.com/bliki/CanaryRelease.html
26

Canary Deployment (cont.)
27

Canary Deployment(cont.)
28

Rolling updates
Rolling updates allow Deployments'
update to take place with zero
downtime by incrementally updating
Pods instances with new ones.
29

Rolling updates (cont.)
If a Deployment is exposed
publicly, the Service will load-
balance the traffic only to
available Pods during the update.
30

31

32

• Allow the following actions:
▪ Promote an application from one environment to another (via container
image updates)
▪ Rollback to previous versions
▪ Continuous Integration and Continuous Delivery of applications with zero
downtime
33

Hands ON…..
34https://pixabay.com/zh/%E9%94%AE%E7%9B%98%E6%89%8B-%E9%94%AE%E7%9B%98-%E8%AE%A1%E7%AE%97-%E9%94%AE%E5%85%A5-2148723/
http://labs.play-with-k8s.com/

Thank you!
macchiang@gmail.com
Kubernetes Taiwan User Group

Kubernetes and devops

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