I'm asking this from the perspective of a CI/CD pipeline and cloud engineer who builds CD pipelines that deploy Kubernetes manifests with e.g. Helm: what is the actual advantage of (Open) GitOps over "CI Ops"? Why should one migrate? I really am struggling to understand the _actual_ benefits.

So far, the only advantages of Open GitOps over CI Ops, which I understand and agree with, is improved security: it's easier and safer to enable the Kubernetes cluster to access the Git server (e.g. regarding corporate firewall policies/governance, using a read-only access token) than allowing the CI/CD system to access the K8s API server. With GitOps, much fewer credentials need to be stored in the CI/CD system: only those required for CI, no longer those required for CD. Fair point.

On the flip side (w.r.t. security), you have new components (the GitOps controller) which is software, and any software introduces new security risks.

Here are two advantages promoted by GitOps enthusiasts and companies that I don't really buy:

1) Auditing: the Git log collects all changes made to our environment(s). Thanks to the GitOps controller, everything declared in Git is also what has been deployed.

Counter argument to 1) The Git log alone is not indicative at all. You can absolutely NOT claim that whatever is in Git is also what is deployed, because some K8s admin can simply log into the cluster and temporarily disable or even uninstall the GitOps operator. This means that auditability only is given when considering both the Git log and the Kubernetes audit logs. So, how is GitOps better than a (CI Ops-style) CD pipeline? Open GitOps enthusiasts bad-mouth CD pipelines because a privileged admin can simply make changes to the cluster in-between deployments with no one noticing - except that you DO notice it, in the Kubernetes audit logs.

2) Continuous reconciliation: GitOps controllers ensure that the deployed manifests always match what is declared in Git.

Counter argument to 2) That's the whole point of a CD pipeline, too. It does not do it all the time (only at the last "helm upgrade" step), but it does not need to. I would generally assume that you limited the access privileges to the K8s cluster to (capable) admins. It is the job of Kubernetes to do the reconciliation for us (e.g. ensuring that all Pods of a Deployment are up). I really don't understand the use case for the META-level reconciliation (of K8s workloads themselves) that GitOps controllers are doing. Is the assumption that you let every hillbilly into the cluster so that they can fiddle with it and you constantly need a GitOps controller to correct people's accidental mistakes? If so, proper access would be a much easier fix for this.

Finally, there are more disadvantages I see with Open GitOps that are not present with CI Ops:

1) It is difficult to learn, due to lack of best practices, e.g. for structuring the Git repositories. You also need to first choose a suitable implementation (is Werf better than Argo, etc.)

2) When using GitOps, CI and CD is done by two separate systems. If a deployment fails, the team needs to know about it, but they won't find this piece of information in their CI system anymore (which would have been the case when using CI Ops). You need to configure your monitoring and alerting system such that your team also get notified if a deployment failed. This may involve e.g. creating alerting rules for the Prometheus metrics emitted by the GitOps controller.

I'm curious about your stance is on this topic.