Debug School: Veeramani

What is Kubernetes?

Veeramani — Thu, 20 Oct 2022 06:18:45 +0000

It is an orchestration tool to manage huge number of applications running on data center.
It takes care of launching or re-launching applications without manual interventions.

Veeramani — Thu, 20 Oct 2022 06:18:30 +0000

No manual interventions required in case any applications go down. Applications will be restarted by Kubernetes.
Load balancing
Scalability
High availability
Containerization help us to run the application in separate environment as a Pod in a node.
Storage for applications are kept outside of node. This makes sure the data is still available even if node goes down.

Veeramani — Thu, 20 Oct 2022 06:18:08 +0000

Data store - To keep the data persistent ( details of pod,node,..etc )
Scheduler - Decide on where to run given application
Api server - Receives the instruction from end user or internal services
Controller manager - There will be a controller manager for objects such as Pod, Node,..etc. The corresponding controller manager of each object will get started to perform its task

Agent - Instantiating Pod and managing it in case it goes down.
Kubeproxy - Setting up the IP for each Pod to make all Pods are accessible from same node or other nodes.

Veeramani — Thu, 20 Oct 2022 06:17:39 +0000

Instantiated by Agent to create a container and run an application
It has number of containers running inside of it.
IP address for Pod will be allocated by kubeproxy
It is atomicity. Once pod deleted, we may not get same pod again. We may get similar Pod.
All Pods will be part of Pod network.
Agent running on worker node keep check with API server to see if there are any instructions to create Pod.
Each container in a Pod is reached through the port number. but Pod is reached through the IP address.