ARO-RP

README

Azure Red Hat OpenShift Resource Provider

⚠ Notice

For information relating to the generally available Azure Red Hat OpenShift v3 service, please see the following links:

• https://azure.microsoft.com/en-us/services/openshift/
• https://www.openshift.com/products/azure-openshift
• https://docs.microsoft.com/en-us/azure/openshift/
• https://docs.openshift.com/aro/welcome/index.html

Quickstarts

• If you have a whitelisted subscription and want to use az aro to create a cluster using the production RP, follow using az aro.

• If you want to deploy a development RP, follow deploy development RP.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repositories using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Repository map

• .github/workflows: CI workflows using GitHub Actions.

• cmd/aro: RP entrypoint.

• deploy: ARM templates to deploy RP in development and production.

• docs: Documentation.

• hack: Build scripts and utilities.

• pkg: RP source code:

  • pkg/api: RP internal and external API definitions.

  • pkg/backend: RP backend workers.

  • pkg/client: Autogenerated ARO service Go client.

  • pkg/database: RP CosmosDB wrapper layer.

  • pkg/deploy: /deploy ARM template generation code.

  • pkg/env: RP environment-specific shims for running in production, development or test

  • pkg/frontend: RP frontend webserver.

  • pkg/install: OpenShift installer wrapper layer.

  • pkg/mirror: OpenShift release mirror tooling.

  • pkg/swagger: /swagger Swagger specification generation code.

  • pkg/util: Utility libraries.

• python: Autogenerated ARO service Python client and az aro client extension.

• swagger: Autogenerated ARO service Swagger specification.

• test: End-to-end tests.

• vendor: Vendored Go libraries.

Basic architecture

• pkg/frontend is intended to become a spec-compliant RP web server. It is backed by CosmosDB. Incoming PUT/DELETE requests are written to the database with an non-terminal (Updating/Deleting) provisioningState.

• pkg/backend reads documents with non-terminal provisioningStates, asynchronously updates them and finally updates document with a terminal provisioningState (Succeeded/Failed). The backend updates the document with a heartbeat - if this fails, the document will be picked up by a different worker.

• As CosmosDB does not support document patch, care is taken to correctly pass through any fields in the internal model which the reader is unaware of (see github.com/ugorji/go/codec.MissingFielder). This is intended to help in upgrade cases and (in the future) with multiple microservices reading from the database in parallel.

• Care is taken to correctly use optimistic concurrency to avoid document corruption through concurrent writes (see RetryOnPreconditionFailed).

• The pkg/api architecture differs somewhat from github.com/openshift/openshift-azure: the intention is to fix the broken merge semantics and try pushing validation into the versioned APIs to improve error reporting.

• Everything is intended to be crash/restart/upgrade-safe, horizontally scaleable, upgradeable...

Useful links

• https://github.com/Azure/azure-resource-manager-rpc

• https://github.com/microsoft/api-guidelines

• https://docs.microsoft.com/en-gb/rest/api/cosmos-db

• https://github.com/jim-minter/go-cosmosdb