The framework validates service configuration with the help of AJV (JSON-schema validation engine).
If you received a configuration warning it could mean that:
Note: A configuration warning doesn't block framework commands in any way by default (e.g.
sls deploy will still attempt to deploy the service). If you wish all deployments to be blocked if there is a configuarion warning, add
configValidationMode: error to your serverless.yml, so the command is not processed further (it is likely to become a default setting in future)
If you find this functionality problematic, you may also turn it off with
configValidationMode: off setting.