Let's say we have a number of Kubernetes configuration files in a folder kubernetes and we want to apply them all:
kubectl apply -f kubernetes -n MyNamespace
Some of these files contain environment variables which need to be substituted first (no templating in Kubernetes). For instance, several of the deployment yamls contain something like:
image: myregistry.com/myrepo:$TAG
For a single yaml file, this can be done e.g. by using envsubst like this:
envsubst < deploy.yml | kubectl apply -f -
What's the best way to do these substitutions for all the yaml files?
(Looping over the files in the folder and calling envsubst as above is one option, but I suspect that it would be preferrable to pass the entire folder to kubectl and not individual files)
This works:
for f in *.yaml; do envsubst < $f | kubectl apply -f -; done