KeyWhiz can be an interesting option when it fits your requirements and you have an established technology stack and business model.
OpenShift excels when you have OpenShift cluster, and both solutions can complement each other managing secrets properly on cluster and application layers.
Each option solves a secrets management problem but bring a new problem - you'd have to implement and maintain it. If you consider getting help with this - check out our DevSecOps as a Service
If you are not ready to consider the implementation of a tool - you can check out our Kubernetes Penetration Testing Service.