kapp VS argo-cd

If you want to take it one step further: you might be applying several resources at a time that are logically one "application". kapp (https://carvel.dev/kapp/) lets you group those together and give them a name, and provides a "terraform-like" experience where it shows you its execution plan before applying updates. So then you might do `ytt -f | kapp deploy -a name-of-thing` Or you could use helm's templating engine but then still pass the resulting yaml to kapp for its unification of the deployment step.

since you mentioned Kubernetes...

> It would be nice if there was a separate state reconciliation system that one could adapt to use with Cue or Dhall or any other frontend

this exactly was thinking behind https://carvel.dev/kapp for Kubernetes (i'm one of the maintainers). it makes a point to not know how you decided to generate your Kubernetes config -- just takes it as input.

> In particular the ability to import other files as semantic hashes seems like a great feature.

it's an interesting feature but seems like it should be unnecessary given that config can be easily checked into git (your own and its dependencies).

i think kubernetes is not a great example in favor of more client state (like tf) since k8s has uniform resource structure (metadata.*) and first class labeling support. but as you point out kubectl doesnt use labels well (at least imho).

when building https://carvel.dev/kapp (which i think of as "optimized terraform" for k8s) the goal was absolutely to take advantage of those k8s features. we ended up providing two capabilities: direct label (more advanced) and "app name" (more user friendly). from impl standpoint, difference is how much state is maintained.

"kapp deploy -a label:x=y -f ..." allows user to specify label that is applied to all deployed resources and is also used for querying k8s to determine whats out there under given label. invocation is completely stateless since burden of keeping/providing state (in this case the label x=y) is shifted to the user. downside of course is that all apis within k8s need to be iterated over. (side note, fun features like "kapp delete -a label:!x" are free thanks to k8s querying).

"kapp deploy -a my-app -f ..." gives user ability to associate name with uniquely auto-generated label. this case is more stateful than previous but again only label needs to be saved (we use ConfigMap to store that label). if this state is lost, one has to only recover generated label.

imho k8s api structure enables focused tools like kapp to be much much simpler than more generic tool like terraform. as much as i'd like for terraform to keep less state, i totally appreciate its needs to support lowest common denominator feature set.

common discussion topics:

kapp - Install, upgrade, and delete multiple Kubernetes resources as one "application"

I really like this approach for simplifying Kubernetes. A few projects similar to OAM in that it provides a higher level "Application" CRD:

https://github.com/vmware-tanzu/carvel-kapp

The code above will create the argocd Kubernetes namespace and deploy the latest stable manifest. If you would like to install a specific manifest, have a look here.

In this blog post, we will demonstrate how easy and fast it is to deploy Sveltos on an RKE2 cluster with the help of ArgoCD, register two RKE2 Cluster API (CAPI) clusters and create a ClusterProfile to deploy Prometheus and Grafana Helm charts down the managed CAPI clusters.

Argo CD

This is cool - I can think of some projects that are amazing as first contributors, and others I can think of that are terrible.

One thing I think the tool doesn't address is why someone should contribute to a particular project. Having stars is interesting, and a proxy for at least historical activity, but also kind of useless here - take argoproj/argo-cd [1] as an example - 14.5k stars, with a backlog of 2.7k issues and an issue tracker that's a real mess.

Either way, I think this tool is neat for trying to gain some experience in a project purely based on language.

[1] https://github.com/argoproj/argo-cd/issues?q=is%3Aissue+is%3...

$ kubectl create namespace argocd //Next, let's apply the yaml configuration files for ArgoCd $ kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml //Now we can view the pods created in the ArgoCD namespace. $ kubectl get pods -n argocd //To interact with the API Server we need to deploy the CLI: $ curl --silent --location -o /usr/local/bin/argocd https://github.com/argoproj/argo-cd/releases/download/v2.4.7/argocd-linux-amd64 $ chmod +x /usr/local/bin/argocd //Expose argocd-server $ kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "LoadBalancer"}}' //Wait about 2 minutes for the LoadBalancer creation $ kubectl get svc -n argocd //Get pasword and decode it. $ kubectl get secret argocd-initial-admin-secret -n argocd -o yaml $ echo WXVpLUg2LWxoWjRkSHFmSA== | base64 --decode

From here, we can explore other developments and tutorials on Kubernetes, such as o11y or observability (PLG, ELK, ELF, TICK, Jaeger, Pyroscope), service mesh (Linkerd, Istio, NSM, Consul Connect, Cillium), and progressive delivery (ArgoCD, FluxCD, Spinnaker).

An interesting feature of ArgoCD is the Pull Request Generator. It's a generator for ApplicationSet. An ApplicationSet is a template of ArgoCD Application associated with a generator. Generator can be a directory: an application will be created for every sub-folder. There is also the Cluster generator that deploy the same Application but in every cluster managed by ArgoCD.

There is also a feature request (yet in open state): https://github.com/argoproj/argo-cd/issues/8591

https://github.com/argoproj/argo-cd is my go to repo.