Kops - Kubernetes Ops

kops is the easiest way to get a production Kubernetes up and running. We like to think of it as "kubectl for clusters".

(Currently work in progress, but working. Some of these statements are forward-looking.)

Some of the more interesting features:

• Written in go, so hopefully easier to maintain and extend, as complexity inevitably increases
• Uses a state-sync model, so we get things like a dry-run mode and idempotency automatically
• Based on a simple meta-model defined in a directory tree
• Can produce configurations in other formats (currently Terraform & Cloud-Init), so that we can have working configurations for other tools also.

Recent changes

Change history is available in HISTORY.md

Installation

We recommend using a release from the Release tab above.

Installation from source

Build the code (make sure you have set GOPATH):

go get -d k8s.io/kops
git checkout release
cd ${GOPATH}/src/k8s.io/kops/
make

• The release branch is where releases are taken from. This is the stable code branch.
• The master branch should also be functional, but is where active development happens, so may be less stable.

(Note that the code uses the relatively new Go vendoring, so building requires Go 1.6 or later, or you must export GO15VENDOREXPERIMENT=1 when building with Go 1.5. The makefile sets GO15VENDOREXPERIMENT for you. Go code generation does not honor the env var in 1.5, so for development you should use Go 1.6 or later)

Bringing up a cluster on AWS

• Ensure you have kubectl installed and on your path. (We need it to set kubecfg configuration.)

• Set up a DNS hosted zone in Route 53, e.g. mydomain.com, and set up the DNS nameservers as normal so that domains will resolve. You can reuse an existing domain name (e.g. mydomain.com), or you can create a "child" hosted zone (e.g. myclusters.mydomain.com) if you want to isolate them. Note that with AWS Route53, you can have subdomains in a single hosted zone, so you can have cluster1.testclusters.mydomain.com under mydomain.com.

• Pick a DNS name under this zone to be the name of your cluster. kops will set up DNS so your cluster can be reached on this name. For example, if your zone was mydomain.com, a good name would be kubernetes.mydomain.com, or dev.k8s.mydomain.com, or even dev.k8s.myproject.mydomain.com. We'll call this NAME.

• Set AWS_PROFILE (if you need to select a profile for the AWS CLI to work)

• Pick an S3 bucket that you'll use to store your cluster configuration - this is called your state store. You can export KOPS_STATE_STORE=s3://<mystatestorebucket> and then kops will use this location by default. We suggest putting this in your bash profile or similar. A single registry can hold multiple clusters, and it can also be shared amongst your ops team (which is much easier than passing around kubecfg files!)

• Run "kops create cluster" to create your cluster configuration:

${GOPATH}/bin/kops create cluster --cloud=aws --zones=us-east-1c ${NAME}

(protip: the --cloud=aws argument is optional if the cloud can be inferred from the zones)

• Run "kops update cluster" to build your cluster:

${GOPATH}/bin/kops update cluster ${NAME} --yes

If you have problems, please set --v=8 and open an issue, and ping justinsb on slack!

Create kubecfg settings for kubectl

(This step is actually optional; update cluster will do it automatically after cluster creation. But we expect that if you're part of a team you might share the KOPS_STATE_STORE, and then you can do this on different machines instead of having to share kubecfg files)

To create the kubecfg configuration settings for use with kubectl:

export KOPS_STATE_STORE=s3://<somes3bucket>
# NAME=<kubernetes.mydomain.com>
${GOPATH}/bin/kops export kubecfg ${NAME}

You can now use kubernetes using the kubectl tool (after allowing a few minutes for the cluster to come up):

kubectl get nodes

Cluster management

• Set up add-ons, to add important functionality to k8s.

• Learn about InstanceGroups, which let you change instance types, cluster sizes etc.

Learn more:

• Read about networking options, including a 50 node limit in the default configuration.

Delete the cluster

When you're done, you can also have kops delete the cluster. It will delete all AWS resources tagged with the cluster name in the specified region.

# NAME=<kubernetes.mydomain.com>
${GOPATH}/bin/kops delete cluster ${NAME} # --yes

You must pass --yes to actually delete resources (without the # comment!)

Other interesting modes:

• Build a terraform model: --target=terraform The terraform model will be built in out/terraform

• Specify the k8s build to run: --kubernetes-version=1.2.2

• Run nodes in multiple zones: --zones=us-east-1b,us-east-1c,us-east-1d

• Run with a HA master: --master-zones=us-east-1b,us-east-1c,us-east-1d

• Specify the number of nodes: --node-count=4

• Specify the node size: --node-size=m4.large

• Specify the master size: --master-size=m4.large

• Override the default DNS zone: --dns-zone=<my.hosted.zone>

How it works

Everything is driven by a local configuration directory tree, called the "model". The model represents the desired state of the world.

Each file in the tree describes a Task.

On the nodeup side, Tasks can manage files, systemd services, packages etc. On the kops update cluster side, Tasks manage cloud resources: instances, networks, disks etc.

Generate a terraform configuration

Kops can also generate a terraform configuration, which you can then apply using terraform, to build a Kubernetes cluster using terraform.

If you are using a version of terraform prior to 0.7, please read about the workaround for earlier versions of terraform.

For more details, please read the how to use terraform to create a Kubernetes cluster