This quickstart shows you how to easily install a Kubernetes cluster on AWS.
It uses a tool called kops
.
kops is an opinionated provisioning system:
If your opinions differ from these you may prefer to build your own cluster using kubeadm as a building block. kops builds on the kubeadm work.
You must have kubectl installed in order for kops to work.
Download kops from the releases page (it is also easy to build from source):
On MacOS:
curl -OL https://github.com/kubernetes/kops/releases/download/1.8.0/kops-darwin-amd64
chmod +x kops-darwin-amd64
mv kops-darwin-amd64 /usr/local/bin/kops
# you can also install using Homebrew
brew update && brew install kops
On Linux:
wget https://github.com/kubernetes/kops/releases/download/1.8.0/kops-linux-amd64
chmod +x kops-linux-amd64
mv kops-linux-amd64 /usr/local/bin/kops
kops uses DNS for discovery, both inside the cluster and so that you can reach the kubernetes API server from clients.
kops has a strong opinion on the cluster name: it should be a valid DNS name. By doing so you will no longer get your clusters confused, you can share clusters with your colleagues unambiguously, and you can reach them without relying on remembering an IP address.
You can, and probably should, use subdomains to divide your clusters. As our example we will use
useast1.dev.example.com
. The API server endpoint will then be api.useast1.dev.example.com
.
A Route53 hosted zone can serve subdomains. Your hosted zone could be useast1.dev.example.com
,
but also dev.example.com
or even example.com
. kops works with any of these, so typically
you choose for organization reasons (e.g. you are allowed to create records under dev.example.com
,
but not under example.com
).
Let’s assume you’re using dev.example.com
as your hosted zone. You create that hosted zone using
the normal process, or
with a command such as aws route53 create-hosted-zone --name dev.example.com --caller-reference 1
.
You must then set up your NS records in the parent domain, so that records in the domain will resolve. Here,
you would create NS records in example.com
for dev
. If it is a root domain name you would configure the NS
records at your domain registrar (e.g. example.com
would need to be configured where you bought example.com
).
This step is easy to mess up (it is the #1 cause of problems!) You can double-check that your cluster is configured correctly if you have the dig tool by running:
dig NS dev.example.com
You should see the 4 NS records that Route53 assigned your hosted zone.
kops lets you manage your clusters even after installation. To do this, it must keep track of the clusters that you have created, along with their configuration, the keys they are using etc. This information is stored in an S3 bucket. S3 permissions are used to control access to the bucket.
Multiple clusters can use the same S3 bucket, and you can share an S3 bucket between your colleagues that administer the same clusters - this is much easier than passing around kubecfg files. But anyone with access to the S3 bucket will have administrative access to all your clusters, so you don’t want to share it beyond the operations team.
So typically you have one S3 bucket for each ops team (and often the name will correspond to the name of the hosted zone above!)
In our example, we chose dev.example.com
as our hosted zone, so let’s pick clusters.dev.example.com
as
the S3 bucket name.
Export AWS_PROFILE
(if you need to select a profile for the AWS CLI to work)
Create the S3 bucket using aws s3 mb s3://clusters.dev.example.com
You can export KOPS_STATE_STORE=s3://clusters.dev.example.com
and then kops will use this location by default.
We suggest putting this in your bash profile or similar.
Run “kops create cluster” to create your cluster configuration:
kops create cluster --zones=us-east-1c useast1.dev.example.com
kops will create the configuration for your cluster. Note that it only creates the configuration, it does
not actually create the cloud resources - you’ll do that in the next step with a kops update cluster
. This
give you an opportunity to review the configuration or change it.
It prints commands you can use to explore further:
kops get cluster
kops edit cluster useast1.dev.example.com
kops edit ig --name=useast1.dev.example.com nodes
kops edit ig --name=useast1.dev.example.com master-us-east-1c
If this is your first time using kops, do spend a few minutes to try those out! An instance group is a set of instances, which will be registered as kubernetes nodes. On AWS this is implemented via auto-scaling-groups. You can have several instance groups, for example if you wanted nodes that are a mix of spot and on-demand instances, or GPU and non-GPU instances.
Run “kops update cluster” to create your cluster in AWS:
kops update cluster useast1.dev.example.com --yes
That takes a few seconds to run, but then your cluster will likely take a few minutes to actually be ready.
kops update cluster
will be the tool you’ll use whenever you change the configuration of your cluster; it
applies the changes you have made to the configuration to your cluster - reconfiguring AWS or kubernetes as needed.
For example, after you kops edit ig nodes
, then kops update cluster --yes
to apply your configuration, and
sometimes you will also have to kops rolling-update cluster
to roll out the configuration immediately.
Without --yes
, kops update cluster
will show you a preview of what it is going to do. This is handy
for production clusters!
See the list of add-ons to explore other add-ons, including tools for logging, monitoring, network policy, visualization & control of your Kubernetes cluster.
kubectl
.kops
advanced usagekops delete cluster useast1.dev.example.com --yes