we have four microservices let's say, Microservice A,B,C&D.we will expose Microservice-A so that It can be accessible over internet to end-users. The end-users should be able to access Microservice B, C&D Via Microservice A. How can we do this in a secure way in google kuberenetes Engine cluster.
Any reference would be help a lot.
You have to use API Gateway kind of thing. An api gateway will be exposed to the outside world and rest of the services can be called through that. You may use Nginx/Kong or your own private API gateway service.
Ref: https://getkong.org/about/
You may deploy Kong on containers and can access them as a Kubernetes service through external load balancer. Rest of the services would use internal load balancer.