How to set secret files to kubernetes secrets by yaml?

You can use --dry-run flag to prepare YAML that contains data from your files.

kubectl create secret generic jwt-certificates --from-file=jwt-public.cer --from-file=jwt-private.pfx --dry-run=true  --output=yaml > jwt-secrets.yaml

Edit

Thanks to @Leopd for comment about API deprecation, new kubectl uses this command:

kubectl create secret generic jwt-certificates --from-file=jwt-public.cer --from-file=jwt-private.pfx --dry-run=client --output=yaml > jwt-secrets.yaml

On my machine I still have old kubectl version

As answered on previous post, we need to provide the certificate/key encoded as based64 to the file.

Here is generic example for a certiticate (in this case SSL):

The secret.yml.tmpl:

    apiVersion: v1    

    kind: Secret
    metadata:
         name: test-secret
         namespace: default
    type: Opaque
    data:
        server.crt: SERVER_CRT
        server.key: SERVER_KEY

Pre-process the file to include the certificate/key:

sed "s/SERVER_CRT/`cat server.crt|base64 -w0`/g" secret.yml.tmpl | \
sed "s/SERVER_KEY/`cat server.key|base64 -w0`/g" | \
kubectl apply -f -

Note that the certificate/key are encoded using base64 without whitespaces (-w0).

For the TLS can be simply:

kubectl create secret tls test-secret-tls --cert=server.crt --key=server.key