“Comparing Containers and Pods in Kubernetes: How They Differ and Why it Matters”

Containers

• Used to run single process per container to get the maximum benefit.
• Provides logical isolation.
• You can run unlimited number of container on virtual machine/physical server based on the capacity.
• Each container can have it’s own libraries and binaries based on application need.
• Encapsulation of application code and it’s dependedcies.
• One IP address per container

Pod

• Wrapper around container
• Can run multiple container within Pod.
• Main process and it’s inter dependent process wrapped inside the pod
• Container within pod share same ip address.

Image courtesy: google

How and why it matters ?

Containers are designed to run single process per container to get the maximum benefit out of it. If the application component has interdependent process than instead of running as 2 different containers or within same container we can make use of pods in kuberenetes.

Functionality of container remain same in Kuberenetes world; however we can take advantage of pods to run multiple container within the pod.

Why one process per container..?

While it’s technically possible to run multiple processes within a single container, it’s generally not recommended for several reasons:

1. Process Isolation: Containers are designed to be small and lightweight, with a single process running inside each container. This makes it easier to manage and scale your application, and allows you to run one app per container.
2. Resource allocation: Running multiple processes within a single container can make it difficult to manage resource allocation. If one process consumes too much CPU or memory, it can affect the performance of other processes running in the same container.
3. Debugging : When you have multiple processes running in the same container, it can be challenging to debug and troubleshoot issues. If one process fails, it can be challenging to isolate the problem and fix it without affecting the other processes.

Instead, it’s recommended to follow the “one process per container” principle, where each container is responsible for running a single process or service. The single process can be referred to separate application or identical copies of same application. This approach makes it easier to manage and scale your application, and helps to ensure that each container has the resources it needs to run effectively. If you need to run multiple processes or services, you can use container orchestration tools like Kubernetes to manage and coordinate multiple containers that work together to provide a complete application.

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