kapp
ytt
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kapp | ytt | |
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7 | 14 | |
859 | 1,582 | |
1.5% | 2.2% | |
8.1 | 6.4 | |
7 days ago | 4 days ago | |
Go | Go | |
Apache License 2.0 | Apache License 2.0 |
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kapp
- HELM vs KUSTOMIZE
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How to handle the lifecycle of multiple COTS
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.
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Dhall: A Gateway Drug to Haskell
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).
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Terraform should have remained stateless
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:
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Is there any CLI tool to sync between local yamls and current cluster namespace state?
Take a look at kapp (https://github.com/vmware-tanzu/carvel-kapp).
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Deploy Neo4J's APOC plugin with code thanks to CARVEL vendir
kapp - Install, upgrade, and delete multiple Kubernetes resources as one "application"
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Open Application Model – An open standard for defining cloud native apps
I really like this approach for simplifying Kubernetes. A few projects similar to OAM in that it provides a higher level "Application" CRD:
ytt
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10 Ways for Kubernetes Declarative Configuration Management
YTT - YTT is a templating tool that understands YAML structure. It helps you easily configure complex software via reusable templates and user provided values using the Starlark language.
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Alternatives to Helm/Kustomize for complex Kubernetes Deployments
Adding https://carvel.dev/ytt/ to the list. I was happy using this tool as IMO it mixes good things from Helm and Kustomize, however the syntax is ugly and repelling my colleagues to have a closer look.
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The YAML Document from Hell
> Templating yaml is a terrible, terrible idea
I've had a good time using ytt: https://carvel.dev/ytt/. It implements language-aware templating, which is IMO the only reasonable way to do it.
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Creating Kubernetes Templates
`ytt` is part of the Carvel toolchain. https://carvel.dev/ytt/
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Dealing with YAML overload
I agree with you on `you will want to see just plain texts instead of a bunch of templating token with hidden logic.` Which is why I think https://carvel.dev/ytt/ would be great. We could generate these templates in pipelines, or we could just make it easier to maintain what we have.
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How to handle the lifecycle of multiple COTS
For more advanced configuration management you might be interested in ytt ( https://carvel.dev/ytt/ ) which is a "yaml-aware" templating tool. it lets you do "patches" via an overlay mechanism to add or remove specific yaml blocks, and it also lets you use a simplified python dialect for more complicated logic. With ytt you would put your DNS IP into a "data values" file and then run ytt to render it into the configs before handing them off to the deployment tool. e.g. `ytt -f | kubectl apply`
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The Dhall Configuration Language
I said this above as well: ytt (https://carvel.dev/ytt/) lets you embed starlark into valid yaml, among other cute tricks for managing biz-logic in configs.
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ArgoCD Instance per kubernetes cluster? (staging and prod)
Manifests are generated with ytt (https://carvel.dev/ytt/).
- Dynamically creating yaml manifests?
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YAML and Configuration Files
This is why you should consider https://carvel.dev/ytt/
What are some alternatives?
kubevela - The Modern Application Platform.
kustomize - Customization of kubernetes YAML configurations
argo-cd - Declarative Continuous Deployment for Kubernetes
cue - CUE has moved to https://github.com/cue-lang/cue
Flux - Successor: https://github.com/fluxcd/flux2
tanka - Flexible, reusable and concise configuration for Kubernetes
kapp-controller - Continuous delivery and package management for Kubernetes.
strictyaml - Type-safe YAML parser and validator.
carvel - Carvel provides a set of reliable, single-purpose, composable tools that aid in your application building, configuration, and deployment to Kubernetes. This repo contains information regarding the Carvel open-source community.
hull - The incredible HULL - Helm Uniform Layer Library - is a Helm library chart to improve Helm chart based workflows
terraform-provider-carvel - Carvel Terraform provider with resources for ytt and kapp to template and deploy to Kubernetes
yaml-rust - A pure rust YAML implementation.