Replicated Ship is a Kubernetes app deployment and automation tool that can:
- Track and automate the maintenance of 3rd-party applications whether packaged as Helm Charts, Kubernetes YAML manifests, or Knative apps.
- Quickly develop app kustomizations using Ship's easy-to-use import & migration tools.
- Enable application developers to package and deliver a canonical version of their application configuration while encouraging last-mile customizations through overlays instead of forking or upstream requests.
Read on for more details on Ship features and objectives, or skip ahead to getting started.
Track and automate the maintenance of 3rd-party applications
Ship enables cluster operators to automatically stay in sync with upstream changes while preserving their custom configurations and extensions (adds, deletes and edits) without git merge conflicts. This is possible because of how the three operating modes of Ship invoke, store and apply Kustomizations, a type of Kubernetes specific patch, produced by a cluster operator.
Customizing Helm Charts, Kube YAML and Knative with Kustomize
Ship exposes the power of Kustomize as an advanced custom configuration management tool for Helm charts, Kubernetes manifests and Knative applications. The easy-to-use UI of Ship (launched via
ship init) calculates the minimal patch YAML required to build an overlay and previews the diff that will be the result of applying the drafted overlay.
unfork command can migrate forked manifests and environment versions to Kustomize.
The output of the
unfork modes will result in the creation of a directory that includes the finalized overlay YAML files, a kustomization.yaml and a Ship state.json.
Enable app developers to allow for last-mile configuration
ship.yaml files can be included in Kubernetes manifest or Helm chart repos, to customize the initial
ship init experience. See Customizing the Configuration Experience for more details or check out the examples in the github.com/shipapps org.
Ship is packaged as a single binary, and Linux and MacOS versions are distributed:
- To download the latest Linux build, run:
curl -sSL https://github.com/replicatedhq/ship/releases/download/v0.41.0/ship_0.41.0_linux_amd64.tar.gz | tar zxv && sudo mv ship /usr/local/bin
- To download the latest MacOS build, you can either run:
curl -sSL https://github.com/replicatedhq/ship/releases/download/v0.41.0/ship_0.41.0_darwin_amd64.tar.gz | tar zxv && sudo mv ship /usr/local/bin
- ... or you can install with Homebrew:
brew install ship
- To download the latest Windows build, grab the tar.gz from the releases page.
Alternately, you can run Ship in Docker, in which case you can pull the latest ship image with:
docker pull replicated/ship
After Ship is installed, create a directory for the application you'll be managing with Ship, and launch Ship from there, specifying an upstream Helm chart or Kubernetes yaml:
mkdir -p ~/my-ship/example cd ~/my-ship/example ship init <path-to-chart> # github.com/helm/charts/tree/master/stable/grafana
Alternately, the same command run through Docker:
mkdir -p ~/my-ship/example cd ~/my-ship/example docker run -p 8800:8800 -v "$PWD":/wd -w /wd \ replicated/ship init <path-to-chart> # github.com/helm/charts/tree/master/stable/grafana
Note: you may need to point your browser to http://127.0.0.1:8800 if ship's suggested localhost URL doesn't resolve.
You'll be prompted to open a browser and walk through the steps to configure site-specific values for your installation, updating Helm values (if it's a chart), and making direct edits to the Kubernetes yaml (or Helm-generated yaml), which will be converted to patches to apply via Kustomize.
After completing the guided 'ship init' workflow, you'll see that Ship has generated several directories and files within the current working directory.
├── .ship │ └── state.json ├── base │ ├── clusterrole.yaml │ ├── ... │ └── serviceaccount.yaml ├── overlays │ └── ship │ └── kustomization.yaml └── rendered.yaml
.ship/state.json - maintains all the configuration decisions made within the
ship init flow, including the path to the upstream, the upstream's original
values.yaml, any modifications made to
values.yaml, and any patch directives configured in the Kustomize phase.
overlays/ folders contain the various files that drive the Kustomization process.
rendered.yaml file is the final output, suitable to deploy to your Kubernetes cluster via
kubectl apply -f rendered.yaml
If you need to revise any of the configuration details, you can re-invoke
ship init <path-to-chart> to start fresh, or
ship update --headed to walk through the configuration steps again, starting with your previously entered values & patches as a baseline.
Three operating modes
Prepares a new application for deployment. Use for:
- Specifying the upstream source for an application to be managed -- typically a repo with raw Kubernetes yaml or a Helm chart
- Creating and managing Kustomize overlays to be applied before deployment
- Generating initial config (state.json) for the application, and persisting that config to disk for use with the other modes
Polls an upstream source, blocking until any change has been published. Use for:
- Triggering creation of pull requests in a CI pipeline, so that third party updates can be manually reviewed, and then automatically deployed once merged
Updates an existing application by merging the latest release with the local state and overlays. Use for:
- Preparing an update to be deployed to a third party application
- Automating the update process to start from a continuous integration (CI) service
Another initialization option is to start with a Helm chart or Kubernetes manifest that has been forked from an upstream source, and to "unfork" it.
ship unfork <path-to-forked> --upstream <path-to-upstream>
docker run -v "$PWD":/wd -w /wd \ replicated/ship unfork <path-to-forked> \ --upstream <path-to-upstream>
With this workflow, Ship will attempt to move the changes that prompted the fork into 'overlays' that can be applied as patches onto the unmodified upstream base. You can inspect the
rendered.yaml to verify the final output, or run through
ship update --headed to review the generated overlays in the Ship admin console.
Once you've prepared an application using
ship init, a simple starting CI/CD workflow could be:
ship watch && ship update
docker run -v "$PWD":/wd -w /wd replicated/ship watch && \ docker run -v "$PWD":/wd -w /wd replicated/ship update
watch command is a trigger for CI/CD processes, watching the upstream application for changes. Running
ship watch will load the local state file (which includes a content hash of the most recently used upstream) and periodically poll the upstream application and exit when it finds a change.
ship update will regenerate the deployable application assets, using the most recent upstream version of the application, and any local configuration from
state.json. The new
rendered.yaml output can be deployed directly to the cluster, or submitted as a pull request into a GitOps repo.
With chart repo you have commit privileges on, you, you can see this flow in action by running
ship init <path-to-chart> and going through the workflow, then
ship watch --interval 10s && ship update to start polling, then commit a change to the upstream chart and see the
ship watch process exit, with
rendered.yaml updated to reflect the change.
Customizing the Configuration Experience
Maintainers of OTS (Off the Shelf) software can customize the
ship init experience by including a
ship.yaml manifest alongside a Helm Chart or Kubernetes manifest. The Replicated Ship YAML format allows further customization of the installation process, including infrastructure automation steps to spin up and configure clusters to deploy to. (If you're wondering about some of the more obscure Ship CLI option flags, these mostly apply to ship.yaml features)
For those not interested in operating and maintaining a fleet of Ship instances, Ship Cloud is available as a hosted solution for free. With Ship Cloud, teams can collaborate and manage multiple OTS Kubernetes application settings in one place, with Ship watching and updating on any upstream or local configuration changes, and creating Pull Requests and other integrations into CI/CD systems.
For bug reports, please open an issue in this repo.
For instructions on building the project and making contributions, see Contributing