gitkube

Gitkube

Gitkube is a tool for building and deploying Docker images on Kubernetes using git push.

After a simple initial setup, users can simply keep git push-ing their repos to build and deploy to Kubernetes automatically.

When should I use gitkube?

1. Ideal for development where you can push your WIP branch to the cluster to test.
2. Reference implementation for writing git-based automation on your server. Fork this repo and create your own CRD + controller + git remote hook that can do things on the Kubernetes cluster.

Features:

• No dependencies except native tooling (git, kubectl)
• Plug and play installation
• Simple public key based authentication
• RBAC ready - Control access to git remotes using RBAC
• Support for namespace based multi-tenancy - Remotes can only deploy to their own namespace
• No assumptions about repository structure

Getting started

Gitkube will run on any Kubernetes vendor/distribution AS IS. In case you find any difficulties in the setup, please comment on #33

Install gitkube

kubectl create -f https://storage.googleapis.com/gitkube/gitkube-setup-stable.yaml

#expose gitkubed service
kubectl --namespace kube-system expose deployment gitkubed --type=LoadBalancer --name=gitkubed

1. Install Gitkube CLI:

   • Linux/MacOS

   curl https://raw.githubusercontent.com/hasura/gitkube/master/gimme.sh | bash
   

   • Windows: download the latest release and add it to your PATH.

2. Use Gitkube CLI to install Gitkube on the cluster:

   gitkube install
   

Provider walkthroughs

The above installation steps work on most Kubernetes clusters. Detailed walkthroughs for few specific providers are also available:

Example

Follow this example repo for a typical workflow of gitkube.

How it works

Gitkube has three components:

1. Remote: Custom resource defined by a K8s CRD
2. gitkube-controller: Controller that manages Remote objects and propogates changes to gitkubed
3. gitkubed: Git host that builds docker image from the repo and rolls out deployment

High-level architecture

Workflow

• Local dev: User creates a base git repo for the application with Dockerfile and K8s deployment
• Setting Remote: User defines a spec for Remote containing the rules for git push
• Deploying application: Once a Remote is setup, application can be deployed to K8s using git push <remote> master

Local dev

User should have a git repo with source code and a Dockerfile. User should also create a base K8s deployment for the application.

Setting Remote

A Remote resource consists of 3 parts:

1. authorizedKeys: List of ssh-keys for authorizing git push.
2. registry: Details of docker registry where images are pushed post-build.
3. deployments: Spec for building docker image and updating corresponding K8s deployment.

Here is a typical spec for a Remote:

apiVersion: gitkube.sh/v1alpha1
kind: Remote
metadata:
  name: sampleremote
  namespace: default
spec:

# Insert ssh-keys for allowing users to git push
  authorizedKeys:
  - "ssh-rsa your-ssh-public-key"

# Provide registry details: https://github.com/hasura/gitkube/blob/master/docs/registry.md
  registry:
    url: "docker.io/user"
    credentials:
      secretRef: regsecret                # Name of docker-registry secret

# Define deployment rules
  deployments:
  - name: www                             # Name of K8s deployment which is updated on git push
    containers: 
    - name: www                           # Name of container in the deployment which is built during git push
      path: example/www                   # Docker build context path in the git repo
      dockerfile: example/www/Dockerfile  # Location of Dockerfile for the source code

Deploying application

Once a Remote is created, it gets a git remote URL which you can find in its status spec

$ kubectl get remote sampleremote -o yaml
...
status:
  remoteUrl: ssh://default-sampleremote@35.225.226.96/~/git/default-sampleremote
  remoteUrlDesc: ""

Add the generated remoteUrl in git

$ git remote add sampleremote ssh://default-sampleremote@35.225.226.96/~/git/default-sampleremote

And finally, git push

$ git push sampleremote master

Roadmap

Gitkube is open to evolution. Some of the features to be added in future include:

• Allowing all apps (daemonset, statefulset) to be deployed using git push. Current support is limited to deployments. #19
• Allowing different git hooks to be integrated #20

Contributing

Gitkube is an open source project licensed under Apache License 2.0

Contributions are welcome.

Community and Support

• Join the Gitkube channel in the Kubernetes Slack group

• 

• Subscribe to the Gitkube mailing list

Maintainers

This project has come out of the work at hasura.io. Current maintainers @Tirumarai, @shahidh_k.

Follow @gitkube to stay updated.

Gitkube logo concept and design by Samudra Gupta.