running production-grade kubernetes on aws

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Running Production-Grade Kubernetes on AWS

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<vadim@doit-intl.com>

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Let’s Play

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Agenda

● What’s new in Kubernetes v1.3● Bootstrapping K8s cluster on AWS● Watchouts & Limitations!

Copyright 2015 Google Inc

Kubernetes 101

Replication controllers create new pod "replicas" from a template and ensures that a configurable number of those pods are running.

Services provide a bridge based on an IP and port pair for client applications to access backends without needing to write code that is Kubernetes-specific.

Replication Controllers ServicesLabels

Labels are metadata that are attached to objects, such as pods.

They enable organization and selection of subsets of objects with a cluster.

Pods

Pods are ephemeral units that are used to manage one or more tightly coupled containers.

They enable data sharing and communication among their constituent components.

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What's new in Kubernetes 1.3

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Release Highlights ● Init Containers (alpha)● Fixed PDs● Cluster Federation (alpha)● Optional HTTP2● Pod Level QoS Policy● TLS Secrets● kubectl set command● UI● Jobs● RBAC (alpha, experimental)● Garbage Collector (alpha)● Pet Sets● rkt runtime● Network Policies● kubectl auto-complete

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Init Containers

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Init Container: register pod to external service

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Init Container: clone a git repo into a volume

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Jobs (pods are *expected* to terminate)

Creates 1...n pods and ensures that a certain number of them run to completion.

3 job types:

● Non-Parallel (normally only one pod is started, unless the pod fails)

● Parallel with fixed count (complete when there is one successful pod for each value in range 1 to .spec.completions)

● Parallel with a work queue

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Job: Work Queue with Pod Per Work Item

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Increased Scale

● Up w/ up to 2k nodes per cluster● Up to 60k pods per cluster

Under the bonnet, the biggest change that has resulted in the improvements in scalability is to use Protocol Buffer-based serialization in the API instead of JSON.

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Multi-Zone Clusters

Deploy clusters to multiple availability zones to increase availability:

● Multiple zones can be configured at cluster creation or can be added to a cluster after the fact.

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Heterogeneous Clusters

Customers can now add different types of nodes to the same cluster.

● NodePools allow for different types of nodes to be joined to a single master, minimizing administrative overhead

● Built-in scheduler changes to allow scheduling to node types with only a configuration change

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Cluster Federation

Deploy a service to multiple clusters simultaneously (including external load balancer configuration) via a single Federated API.

● Federated Services span multiple clusters (possibly running on different cloud providers, or on premise), and are created with a single API call.

● The federation service automatically:○ deploys the service across multiple clusters in the federation○ monitors the health of these services○ manages DNS records to ensure that clients are always

directed to the closest healthy instance of the federated service.

More info:● Sneak peek video

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New kubectl commands

A new command kubectl set now allows the container image to be set in a single one-line command.

$ kubectl set image deployment/web nginx=nginx:1.9.1

To watch the update rollout and verify it succeeds, there is now a new convenient command: rollout status. So, for example, to see the rollout of nginx/nginx:1.9.1 from nginx/nginx:1.7.9:

$ kubectl rollout status deployment/web

Waiting for rollout to finish: 2 out of 4 new replicas has been updated...Waiting for rollout to finish: 2 out of 4 new replicas has been updated...Waiting for rollout to finish: 2 out of 4 new replicas has been updated...Waiting for rollout to finish: 3 out of 4 new replicas has been updated...Waiting for rollout to finish: 3 out of 4 new replicas has been updated...Waiting for rollout to finish: 3 out of 4 new replicas has been updated...deployment nginx successfully rolled out

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clusters can now automatically request more compute when the have scheduled more jobs than there is CPU or memory available

● If there are no resources in the cluster to schedule a recently created pod, a new node is added.

● If a nodes is underutilized and all pods running on it can be easily moved elsewhere, then the node can be drained and deleted.

● Pay only for resources that are actually needed and get new resources when the demand increases.

Cluster Autoscaling (alpha)

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Improved dashboard

Manage Kubernetes almost entirely through a web browser.

● All workload types are now supported, including DaemonSets, Deployments and Rolling updates

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Minikube

Minikube is a new local development platform for Kubernetes, so customers can begin developing on their desktop or laptop.

● Packages and configures a Linux VM, Docker and all Kubernetes components, optimized for local development

● Can be installed with a single command● Alongside the regular pods, services and controllers, supports advanced

Kubernetes features: ● DNS● NodePorts● ConfigMaps and Secrets● Dashboards

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The new "PetSet" object provides a raft of features for supporting containers that run stateful workloads (such as databases or key value stores), including:

● Permanent hostnames, that persist across restarts

● Automatically provisioned Persistent Disks per-container, that live beyond the life of a container

● Unique identities in a group, to allow for clustering and leader election

● Initialization containers, which are critical for starting up clustered applications

Stateful workload support (Pet Sets)In Alpha in Kubernetes 1.3

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What's coming next

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New features for Kubernetes in 1.4● Full cross-cluster federation, including

○ Single universal API

○ Global load balancer

○ Replica sets that span multiple clusters

● Granular permissions for clusters

● Simplified installation for common applicationsOne line install for simple applications in fully tested configurations

● Universal setupGreatly simplified on-prem and complex cloud deployments

● Integrated external DNS (including Route53)Simplified integration with external DNS providers

Expected release date for 1.4 is 16 September

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Deploying K8s to Amazon AWS

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What we wanted to achieve...

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4.5 Step Deployment into existing VPC

Based on CoreOS K8s project:

$ kube-aws init & adjust your cluster.yaml

$ kube-aws render (generates CF stack)

$ kube-aws validate

$ kube-aws up (deploys the CF stack)

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What you get...

CloudFormation Stack w/:

● Controller (master) node with EIP

● Autoscaling Group/Launch Config for Worker Nodes (fixed scaling)

● A Record in Route53 for Controller

● Security Groups to allow traffic between controller and works

● IAM Roles for both Controller and Workers

● AWS Addons (ELB, EBS integration)

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Watchouts!

etcd high availability - build your own etcd cluster and expose it with internal ELB (CF stack)

default TLS keys 90-days expiration - replace generated TLS assets with your own

master/controller sizing - m3.xlarge for < 100 nodes - m3.2xlarge for < 250 nodes - c4.4xlarge > 500 nodes

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Limitations

can’t deploy the cluster into existing subnets - the fix is on the way in 0.9

pv/pvc are available only in the same zone - because ebs volumes available in single AZ

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Scaling the cluster

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Exposing Services

$ kubectl expose deployment nginx --port:80 --type=”LoadBalancer”

kind: ServiceapiVersion: v1metadata: name: nginx annotations: service.beta.kubernetes.io/aws-load-balancer-internal: 0.0.0.0/0

Externally with ELB (nodePort implementation)

Internally with ELB:

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Persistent Volumes/Claims

EBS Volumes (available in single AZ)

EFS Volumes (multi AZ but with require manual recovery)

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Spot Instances

Import ASG to Spotinst’s Elastigroup

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