Interview Q&A / Docker & Kubernetes
Docker & Kubernetes interview questions
Images, containers, Dockerfiles, pods and deployments, from first principles.
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- Does EXPOSE in a Dockerfile make a port reachable from outside?
No. EXPOSE is only documentation of the port the app listens on. To make it reachable from the host you must publish it with -p, or -P to publish all exposed ports to random host ports.
BeginnerQuick answer1 min read - How can two Docker containers talk to each other?
Put them on the same user-defined network and call one from the other using its container or service name and the container port. Publishing a port with -p is only needed for access from the host.
BeginnerQuick answer1 min read - What are the bridge, host and none network modes in Docker?
bridge (default) gives a container its own network and IP behind a virtual switch, host shares the host's network stack with no isolation, and none disables networking except loopback.
BeginnerQuick answer1 min read - What are the different Service types in Kubernetes?
ClusterIP exposes a Service only inside the cluster, NodePort opens a port on every node, LoadBalancer provisions a cloud load balancer, and ExternalName maps the Service to an external DNS name.
BeginnerQuick answer1 min read - What is an Ingress in Kubernetes and how does it differ from a LoadBalancer Service?
An Ingress defines HTTP and HTTPS routing rules by host and path, handled by an Ingress controller. One load balancer can serve many services, while a LoadBalancer Service creates one external load balancer per Service.
BeginnerQuick answer1 min read