I'm trying to deploy Node.js code to a Kubernetes cluster, and I'm seeing that in my reference (provided by the maintainer of the cluster) that the yaml files are all prefixed by numbers:
00-service.yaml
10-deployment.yaml
etc.
I don't think that this file format is specified by kubectl, but I found another example of it online: https://imti.co/kibana-kubernetes/ (but the numbering scheme isn't the same).
Is this a Kubernetes thing? A file naming convention? Is it to keep files ordered in a folder?
When you execute kubectl apply * the files are executed alphabetically. Prefixing files with a rising number allows you to control the order of the executed files. But in nearly all cases the order shouldn't matter.
This is to handle the resource creation order. There's an opened issue in kubernetes: https://github.com/kubernetes/kubernetes/issues/16448#issue-113878195
tl;dr kubectl apply -f k8s/* should handle the order but it does not.
However, except the namespace, I cannot imagine where the order will matter. Every relation except namespace is handled by label selectors, so it fixes itself once all resources are deployed. You can just do 00-namespace.yaml and everything else without prefixes. Or just skip prefixes at all unless you really hit the issue (I never faced it).
Sequence helps in readability, user friendly and not the least maintainability. Looking at the resources one can conclude in which order the deployment needs to be performed. For example, deployment using configMap object would fail if the deployment is done before configMap is created.