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#Spread: Git for Kubernetes

spread is a command line tool that makes it easy to version Kubernetes clusters, deploy to Kubernetes clusters in one command, and set up a local Kubernetes cluster (see: localkube). The project's goals are to:

• Guarantee reproducible Kubernetes deployments
• Be the fastest, simplest way to deploy Docker to production
• Enable collaborative deployment workflows that work well for one person or an entire team

See how we versioned the cluster running our (website) (and you can too!):

Spread is under open, active development. New features will be added regularly over the next few months - explore our roadmap to see what will be built next and send us pull requests for any features you’d like to see added.

See our philosophy for more on our mission and values.

##Requirements

• Running Kubernetes cluster (remote or local)
• Git
• Go (v 1.6)

##Installation

Install with go get (-d is for download only):

go get -d rsprd.com/spread/cmd/spread

Go into the correct directory:

cd $GOPATH/src/rsprd.com/spread

If libgit2 is not installed:

make install-libgit2

Then:

make build/spread

If an error about libraries missing comes up, set up your library path like:

export LD_LIBRARY_PATH=/usr/local/lib:$ LD_LIBRARY_PATH

Or, if you prefer using Homebrew (OS X only):

$ brew tap redspread/spread
$ brew install spread-versioning

##Git for Kubernetes

Spread versions your software environment (i.e. a Kubernetes cluster) like Git versions source code. Because Spread is built on top of libgit2, it takes advantage of Git's interface and functionality. This means after you deploy a Kubernetes object to a cluster, you can version the object by staging, commiting, and pushing it to a Spread repository.

To get started, initialize Spread and set up a local Spread repository:

spread init

Here is our suggested workflow for versioning with Spread:

1. Create or edit your Kubernetes objects
2. Deploy your objects to a local or remote Kubernetes cluster (make sure you've set up your directory correctly): spread deploy .
3. Stage an object: spread add <objectType>/<objectName>
4. Repeat until all objects have been staged
5. Commit your objects with a message: spread commit -m "commit message"
6. Set up your remote repository: spread remote (add <name> <url> | remove <name> | set-url <name> <url>)
7. Push your objects to your remote repository: spread push <remote> <refSpec>
8. Go ahead and try out the other commands - anything not documented can be accessed using spread git ...

If you find any bugs or have any feature requests for Spread versioning, please file an issue!

For more details on Spread commands, see our docs.

##Spread Deploy Quickstart

Check out our Getting Started Guide.

##Localkube --> Minikube

Spread made it easy to set up and iterate with Localkube, a local Kubernetes cluster streamlined for rapid development. We have donated Localkube code to Minikube, the official Kubernetes local development solution. It's easy to set up a local cluster with Minikube: https://github.com/kubernetes/minikube.

##What's been done so far

• Spread versioning
• spread deploy [-s] PATH [kubectl context]: Deploys a Docker project to a Kubernetes cluster. It completes the following order of operations:
  • Reads context of directory and builds Kubernetes deployment hierarchy.
  • Updates all Kubernetes objects on a Kubernetes cluster.
  • Returns a public IP address, if type Load Balancer is specified.
• localkube: easy-to-setup local Kubernetes cluster for rapid development
• Initial tutorial for templating and parameterization

##What's being worked on now

• Template authoring
• Secret management with Spread versioning
• Inner-app linking
• Redspread (hosted Spread repository)

See more of our roadmap here!

##Future Goals

• Peer-to-peer syncing between local and remote Kubernetes clusters
• Automatically spin up local and remote Kubernetes clusters with minimal user input

##FAQ

How are clusters selected? Remote clusters are selected from the current kubectl context. Later, we will add functionality to explicitly state kubectl arguments.

How should I set up my directory? In order to take advantage of Spread's one-command deploy feature, spread deploy, you'll need to set up your directory with a few specific naming conventions:

• All ReplicationController and Pod files should go in the root directory
• Any ReplicationController files should end in .rc.yaml or .rc.json, depending on the respective file extension
• Any Pod files should end in .pod.yaml or .pod.json, depending on the respective file extension
• All other Kubernetes object files should go in a directory named rs

There is no limit to the number of ReplicationControllers or Pods in the root directory.

Here is an example directory with Spread's naming conventions:

app.rc.yaml
database.rc.yaml
rs
 |_
    service.yaml
    secret.yaml

Why version objects instead of just files? The object is the deterministic representation of state in Kubernetes. A useful analogy is "Kubernetes objects" are to "Docker images" like "Kubernetes object files" are to "Dockerfiles". By versioning the object itself, we can guarantee a 1:1 mapping with the Kubernetes cluster. This allows us to do things like diff two clusters and introduces future potential for linking between objects and repositories.

##Contributing

We'd love to see your contributions - please see the CONTRIBUTING file for guidelines on how to contribute.

##Reporting bugs If you haven't already, it's worth going through Elika Etemad's guide for good bug reporting. In one sentence, good bug reports should be both reproducible and specific.

##Contact Team: [email protected]
Slack: slackin.redspread.com
Planning: Roadmap
Bugs: Issues

##License Spread is under the Apache 2.0 license. See the LICENSE file for details.