I use my preferred language to emit manifests and built tooling around it. It does not template, and instead generates the manifest by transforming a data structure (hash) into json. I can then use whatever language feature or library I need to generate that data structure. This is much easier to work with than trying to edit template files.
I don't need to save the output of these because when I use the tooling, it generates and feeds that directly into kubectl. There's also a diff tool that works most of the time that lets me see what I am about to change before changing it.
In fact, I ended up adding a wrapper for Helm so that I can have all the various --set and values, source chart, chart repo, chart version pinning all versioned in git, and use the same tooling to apply those with the flags to install things idempotently turned on by default. It sets that up and calls helm instead of kubectl.
That tooling I wrote is open-source. You never heard of it because (1) I don't have the time and energy to document it or promote it, and (2) it only makes sense for teams that use that particular language. Helm is language-agnostic.
EDIT: and reading this thread, someone mentioned Kustomize. If that had been around in '16, I might not have written my own tool. It looks like it also treat YAML manifests as something to be transformed rather than templates to be rendered.
For better or for worse Helm is the defacto standard for deploying into k8s. Kustomizing toy apps or simple things may work but I have yet to see a large production stack use anything but Helm.
Definitely check out kustomize, it's not a toy and it can easily handle one main manifest with specializations for each unique deployment environment. It's a very nice model of override and patching config instead of some insane monster template and yaml generation like helm.
Large clusters, about 80 service teams and many hundreds of apps.
We (the platform team) managed roughly 30-40 services or controllers, including cert-manager, our own CRD for app deployments, ElasticSearch, Victoria Metrics, Grafana and others.
It was (still is, only I'm sadly not there anymore!) a high performing team and organisation with a lot going on.
We reviewed the decision to not use Helm many times and every time it was pretty much unanimous that we had a better solution than the opaque and awkward templating.
I'm not using Makefile either.
Helm is a kind of least-common denominator software that's better than doing nothing, but the template paradigm leaves a lot to be desired. It's main advantage is being language-agnostic.
Taken straight from their docs.
The entire existence of helm is superfluous. The features it provides are already part of Kubernetes. It was created (by /) for people who understand the package manager metaphor but don't understand how Kubernetes fundamentally works.
The metaphor is wrong! You are not installing applications on some new kind of OS. Using helm is like injecting untracked application code into a running application.
At best helm is just adding unnecessary complexity by re-framing existing features as features that helm adds.
In reality helm's obfuscation leads to an impenetrable mess of black boxes, that explodes the cost and complexity of managing a k8s cluster.
First off if you are packaging and/or publishing apps using helm charts, stop it!
There is purpose to the standardization of the Kubernetes configuration language. Just publish the damn configuration with a bit of documentation.... You know just like every other open source library! You're building the configuration for the helm chart anyway, so just publish that. It's a lot less work then creating stupid helm charts that serve no purpose but to obfuscate.
Here is your new no helm instructions: We've stopped using helm to deploy our app. To use our recommended deployment, clone this repo of yaml configs. Copy these files into your kubernetes config repo, change any options you want (see inline comments). Apply with `kubectl apply -f .`, or let your continuous deployment system deploy it on commit.
What have you lost?
(Or, hell, helm but with no templating whatsoever).
kustomize? raw manifests? "sed s/MY_PER_DEPLOYMENT_VALUE/whatever/" < manifest.yaml | kubectl apply -f -"? "jsonnet whatever.jsonnet | kubectl apply -f -"?
But yeah, a lot of people think Helm is mandatory and ask for it by name, and if you don't provide a chart they won't use your thing.
kubectl apply -f $MANIFESTS
> you're still going to be using Helm (if not indirectly via Argo) and you will inevitably need to template things that need to be dynamically configured at render-time.
Use Kustomize for dynamic vars and keep it at a minimum. Templating is the root of all evil.
Helm mostly adds unnecessary complexity and obscurity. Sure it's faster to deploy supporting services with it, but how often do you actually need to do that anyway ? The time you're initially gaining by using Helm might generate an order of magnitude more time in maintenance later on because you've created a situation where the underlying mechanics are both hidden and unknown from you.
How do you configure it? Like you're installing new version, do you go over manifests and edit those by hand over and over every update? Do you maintain some sed scripts?
helm is awesome because it separates configuration.
But for Kubernetes manifests specifically, the right tool for the job is Kustomize[1] (which in that case does what Helm does for you, keeping dynamic variables separate). It ships with kubectl and I'm a big believer in using default tools when possible.
> Like you're installing new version, do you go over manifests and edit those by hand over and over every update?
I check the patch notes, diff the configuration files to see if anything new popped up, do the required changes if necessary, jump the version number and deploy.
It sounds laborious but it's really not that much work most of the time, and more importantly it forces you to have a good sense for what and how everything works. Plus it allows you to have a completely transparent, readable environment. Both are important for keeping things running in a production environment. Otherwise you might find yourself debugging incomprehensible systems you've never paid attention to in the middle of the night with 2 hours left before traffic starts coming in.
[0]: https://github.com/mikefarah/yq
[1]: https://kustomize.io
Something simple like GitLab probably would be impossible to understand for a simple person.
That blog post doesn't alleviate any issues one might have using the traditional Go Templates + Helm.
Gives you a Typescript API for generating resources. The difference is that these templates are semantic (via the type system) not just syntactic as in text templates. Relatedly, they also factor and compose better because functions and imports.
The one thing it misses is a way to easily delete resources.