My latest blogs: Understanding Kubernetes Architecture: A Comprehensive Guide: https://t.co/L97g5H4OTN Essential Cloud Computing Concepts Simplified: https://t.co/rhJDwn4hLc Simple Steps to Upgrade Your Kubernetes Cluster:

BestEffort QoS class - Requests and limits are not set in pod manifest file.

Among the above three QoS classes, the BestEffort class has the lowest priority and the Guaranteed class has the highest. Burstable lies in between.

Obviously, it depends. Kubernetes can't make a proper decision on its own. You need a way to specify which pods have priority in such cases. Kubernetes does this by categorizing pods into three Quality of Service (Qos) classes: ✴ BestEffort ✴ Burstable ✴ Guaranteed

Should it be pod B, because its request for memory can't be satisfied, or should pod A be killed to free up memory, so it can be provided to pod B?

Imagine having two pods, where pod A is using 90% of the node's memory and then pod B suddenly requires more memory than what it had been using up to that point and the node can't provide the required amount of memory. Which container should be killed?

Kubernetes Pod's QoS classes ⏬👇

Both users and service accounts are associated with groups.

Applications in pods are associated with a service account.

Clients of the API server include both human users and applications running in pods.

Validating the resource and storing it persistentently.

Validating and/or modifying the resource in the request with admission control plugins.

Authorizing the client with authorization plugins.

Authenticating the client with authentication plugins.

Functions of API Server:👇

kubectl replace ⏬

kubectl apply ⏬

kubectl patch ⏬

kubectl edit ⏬

This field is however not mandatory. If you omit the property from the spec and the image mentioned in the container doesn't have a tag, then imagePullPolicy defaults to 'Always'.

This property has to be set in the container level.