Open-source Octopus Deploy alternatives

Harness Open Source is a developer platform written in Go that bundles source code hosting, automated pipelines, hosted development environments and artifact registries in one product. The idea is to give a team a complete, self-run DevOps toolchain rather than separate services for repositories, builds and package storage.

Its hosted development environments are called Gitspaces, and the platform also includes registries for build artifacts. Harness is presented as the next generation of Drone: Drone focused only on continuous integration, whereas Harness adds code hosting and developer environments. The maintainers say the goal is eventual parity with Drone's pipeline capabilities so users can migrate, and a snapshot of Drone lives on a separate branch so it can keep developing.

You can run Harness locally from the published Docker image and open it on port 3000. The image stores its database and repositories in a volume, so a bind mount or named volume is strongly recommended to avoid losing data when the container stops. The project is Apache-2.0 licensed, with documentation at developer.harness.io.

Argo CD applies GitOps principles to continuous delivery on Kubernetes, in a declarative way. Its premise is that application definitions, configuration and environments should be declarative and version controlled, and that rolling out and managing applications should be automated, traceable and straightforward. It is written in Go, is part of the Argo project under the CNCF, and is released under the Apache-2.0 license.

Repository topics show support for Helm, Kustomize and Jsonnet as ways to describe applications, alongside a focus on continuous deployment pipelines. The project offers complete documentation and a live demo, and the community can be reached through GitHub Discussions, a Slack channel, contributor office hours and monthly user community meetings. Its README links to many blog posts and talks on combining Argo CD with tools such as Crossplane, Argo Workflows and preview environments for pull requests.

Kamal is a deployment tool for web applications that can run anywhere, from bare metal servers to cloud virtual machines. It uses a proxy component called kamal-proxy to switch requests between containers without downtime, and it works across multiple servers by running commands over SSH using SSHKit.

Originally built for Rails applications, Kamal works with any web app that can be packaged in a Docker container. Documentation on installation, configuration and commands is on kamal-deploy.org, and the documentation itself lives in a separate repository where improvements are welcome.

Kamal is written in Ruby, developed by Basecamp, and released under the MIT license. Because it deploys to servers you control, it suits teams who want a simple alternative to hosted platforms while still getting rolling, zero-downtime releases.

Komodo is an open-source tool for building and deploying software across many servers. It is intended for people who run their own infrastructure and want a single place to manage builds and deployments on all of their machines, rather than logging in to each one separately.

The project states that there is no limit on the number of servers that can be connected and no restriction on the API available for automation. Servers are connected through a component called Periphery, which has its own setup guide, and the maintainers publish a roadmap, a public demo and a build server for people who want to look around. Screenshots show both light and dark themes.

Komodo is written in Rust and released under GPL-3.0. The maintainers warn that, although they try to keep releases stable, the software comes with no warranty, so it should be used at your own risk. Documentation is available on the project site and community discussion happens on Discord.

Flux version 2 is a continuous delivery tool for Kubernetes. It keeps clusters in sync with sources of configuration, such as Git repositories and OCI artifacts, and automates updates to that configuration when new code is ready to deploy.

Flux v2 is built on Kubernetes' API extension system and the GitOps Toolkit, which bundles composable APIs with specialized controllers. Source controllers handle resources such as GitRepository, OCIRepository, HelmRepository, HelmChart and Bucket, and a Kustomize controller applies the configuration. It supports multi-tenancy, syncing multiple Git repositories, managing Helm releases, automating image updates back to Git and handling secrets with SOPS. It also integrates with Prometheus.

Flux is written in Go, licensed under Apache-2.0 and is a graduated project of the Cloud Native Computing Foundation. The documentation includes a bootstrap guide for installing it on a cluster and deploying a sample app in a GitOps manner, and teams can extend it with the toolkit to build their own delivery systems.

GoCD is a continuous delivery server that helps automate and streamline the build, test and release cycle so that software can be delivered continuously with fewer worries. The repository is the project's main code base, and the project is sponsored by Thoughtworks.

Newcomers can use the Test Drive GoCD page to build a first pipeline while learning the key concepts, download releases from the website and read the documentation for detailed help. It is predominantly a Java and TypeScript project that uses the Spring Framework, SparkJava and MithrilJS, is built with Gradle and Webpack and runs inside Eclipse Jetty, with a few older parts rendered server-side in JRuby on Rails. GoCD itself is built with GoCD.

The security policy explains how issues are reported, and contributing guides cover the development environment. GoCD is licensed under Apache-2.0 and is hosted by you. It suits teams that model deployment pipelines with explicit stages and dependencies across several services.