Argo CD notes

Argo CD (github source) is a Continuous Delivery tool done “GitOps” style. Here, that means keeping all of your (Kubernetes) application definitions and configurations under source code control (git).

Assuming you follow GitOps CI/CD best practices of separate repositories (one for application code and a second for your YAML configurations), your development process is likewise split into two discrete problems:

  1. Application Code – build the container images (CI)
  2. Configuration Code – keep your (Kubernetes) configuration files synchronized with the repository (CD)

Argo CD solves the second bullet. And does it pretty well. It supports writing your configuration code in any of: plain YAML, Helm charts. Kustomize, and Jsonnet.

It also supports enforcing that all Kubernetes changes “from the command line” are at least detected (and if desired, automatically rolled back). E.g. if some rogue administrator issues a “kubectl scale –replicas=3 …” command, Argo CD will at least change the status to “Out of Sync”, and is capable of automatically re-synchronizing, and therefore un-doing the change.

Reference: compare Argo CD versus Tekton versus Jenkins X

Question: do you need separate repositories or just separate directories? i.e. Argo CD takes a repository and a path to configure an “application” – does it ignore commits to files outside of the directory? Answer: yes, it ignores them, so no, you don’t technically need separate repositories. Which means all of the Monorepo fans out there are in luck.

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