Docker
Usage of Docker, focusing on pure usage of containers and images without any orchestration system

Fundamentals
What is the difference between an image and a container at a high level?
What makes up a docker image?
How does a user login to a docker registry and pull an image from that registry?
How does docker image tagging work?
What is a cgroup and a namespace?
Why do processes in a container show as starting from PID 0/1 even if the processes are actually a different PID on the host?
What is the difference between a host volume and a normal docker volume?
What is the difference between Docker and Containerd?
Build
How is a docker image built from a Dockerfile?
Why can an ADD or COPY statement not access files in the parent directory to the Dockerfile?
When should an ENV vs an ARG statement be used in a Dockerfile?
Why should applications in containers be configured to log to STDOUT?
What is layer caching and how does it affect the building of an image?
What is an intermediate container?
Why does creating and removing a file in separate RUN statement in a Dockerfile result in an image which is the same size as if the file existed?
What is a multi step build and why is it beneficial?
When is .dockerignore useful?
Why are images based on Scratch or Alpine preferable to Centos or Ubuntu?
Run
How does a user run a container interactively?
What is the difference between running a container with the flag --publish 80 vs --publish 80:80?
What happens to a container when it stops and what can be done with it?
How can a docker container run docker commands against the host its on?
How can a container run as a non root user and why is that preferable?
How can a container be started with a host volume attached
Manage
How does a user view running and stopped containers on a machine?
How does a user view labels and other metadata for an image or container?
How does a user view STDOUT for a running container?
How can a user run commands in an already running container?
How does a user view and clean up dangling containers and images?
What is the problem that dumb-init solves?
Kubernetes
Usage of Kubernetes, focussing on inside the kubernetes ecosystem, not cluster management

Fundamentals
How does a user set up a local k8s environment?
How does a user log into a k8s cluster with kubectl and how does a user switch between clusters once logged in?
What is a namespace?
What is a label and a selector in kubernetes?
Resources
What are the 3 fields that every k8s resource definition file (yml/json) needs?
Why do different resources have a different api field value?
What is the difference between a label and an annotation in a resource?
Pods
What is the difference between a pod and a container?
How does a user view logs for a running pod?
How do the containers in a pod communicate to each other?
How can environment variables be directly set against a Pod?
How can environment variables be set against a pod using a ConfigMap?
What is a PersistentVolume and how can it be used with a pod?
What is the difference between a Readiness Probe and a Liveness Probe?
What is an init container and when should it be used?
Sets
What is a ReplicaSet and when is it used?
What is the difference between a Deployment and a ReplicaSet?
How does a user scale up pods in a ReplicaSet (hint: there are more than one, and some are automatic)?
What is a DaemonSet and when is it used?
What is a StatefulSet and when is it used?
Load Balancing
If a service with a name of 'mysql' is deployed, why can pods in that namespace access that service using only the hostname 'mysql'?
What is the difference between a ClusterIP, NodePort and LoadBalancer service type?
What is an ingress controller?
What is the difference between an Ingress resource and a Service resource?