This gem provides a set of Rake tasks for a convention based Kubernetes integration. This means that by following some conventions you will be able to leverage some low level kubectl commands using Rake.

These Rake tasks provide a set of high level customizable commands with sensible defaults. Not everyone in your teams has to be an expert in the Docker/Kubernetes/Ops area to interact with a Kubernetes cluster. Activek8s can help teams working on any project, this isn't a Rails only solution (not even a Ruby only solution).


$ gem install activek8s

Ruby/Rails project

Add this line to your application's Gemfile:

gem 'activek8s'

How it works

This gem uses a directory named kube as a workspace for deployment.yml. This YAML file must contain a ConfigMap, Service and Deployment representing the current projects service to be deployed in a Kubernetes cluster. When managing a deployment in a Kubernetes cluster a very common command is kubectl apply -f <config yml file>.

Activek8s performs template-like text substitution on your deployment.yml to output a file named last_deployment.yml. This last_deployment.yml file is the one applied against the currently authenticated Kubernetes cluster (via kubectl). This text substitution is meant for container image name, container image tags and environment management (dev/staging/prod).

Directory structure

├── Dockerfile
├── kube
│   └── deployment.yml

Things you'll need

  1. A Kubernetes cluster somewhere
  2. kubectl authenticated to that cluster from #1 (if kubectl get pods -n NAMESPACE works you're good)
  3. A Dockerized project ready to be deployed on #1 or some other services already deployed to #1


  • ak8s:deploy
    • Creates a last_deployment.yml from deployment.yml and applies the YAML specification on the currently authenticated Kubernetes cluster
    • Ex: kubectl apply -f kube/last_deployment.yml
  • ak8s:delete
    • Creates a last_deployment.yml from deployment.yml and deletes the matching YAML specification on the currently authenticated Kubernetes cluster
    • Ex: kubectl delete -f kube/last_deployment.yml
  • ak8s:port_forward
    • Port forwards all services defined in .ak8s.yml.
    • Will create a file named services.env containing your service names and urls which you can source (i.e. . services.env)
  • ak8s:port_forward_current
    • Port forwards the current project's deployment in a certain namespace defined in .ak8s.yml.
    • Ex: kubectl port-forward {service} ...


This file lets you configure your port forwarding capabilities. Suppose an environment where you have 5 services deployed in a cluster. You would have something similar to the following:

dev:                          # First level keys are namespaces in your cluster.
  - name: webapp              # Inside the list of services to forward the only
  - name: backendwebapp       # required field is 'name'.
  - name: webapi
  - name: analytics
  - name: elasticsearch

  - name: webapp        
  - name: backendwebapp
  - name: webapi              # You can specify the namespace of any service.     
  - name: analytics           # This would cause the port forwarding to occur
    namespace: logging        # referencing the service deployed on a specific
  - name: elasticsearch       # namespace other than the first level key.

  - name: webapp
  - name: backendwebapp
  - name: webapi
  - name: analytics           # Target port specification allows you to pass in
    target_port: 8080         # the target port of the service (not on the
  - name: elasticsearch       # localhost port where the service will be available
    target_port: 9200

ak8s:                         # ak8s is where general config goes
  first_port: 4200            # first_port lets you specify the first port where
                              # the multiple service port forwarding will start

Port forwarding examples

rake ak8s:port_forward will port forward all the services listed by name in the 'dev' namespace because it was listed first.

rake ak8s:port_forward[staging] will port forward all the services listed within the staging namespace. In this case the elasticsearch service will be port forwarded using the logging namespace, instead of using the default (which is the corresponding first level key, 'staging' in this case).


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at


The gem is available as open source under the terms of the MIT License.