Can we have a single container with multiple image like nginx + Redis + alpine?
Is this possible?
Not...really? A container boots from a single image. On the other hand, you can certainly create a single image that includes all of those services:
Using a multi-stage build you could combine content from multiple images, but you would be merging it into a single image.
You could just install them your on top of an Alpine base image.
In either case, your pod would probably still have multiple containers.
Kubernetes allows pods to have multiple containers running as sidecars, each running as an independent process but having the capability to work together. The different containers that form a pod are scheduled on the same VM.
The ideal way to achieve what you need would be to have individual containers for Redis, Nginx and Memcached. These will then need to be scheduled as a pod.
You can refer to this for basic understanding - https://kubernetes.io/docs/concepts/workloads/pods/#how-pods-manage-multiple-containers