Debug School: Harish Kumar G

Day 3- Learning summary - Harish Kumar G

Harish Kumar G — Thu, 19 Oct 2023 04:14:52 +0000

What are the ways to deploy pod?

POD
Replication controller
ReplicationSets
Deployement

Daemon Set
Job & CronJob
ConfigMap
Services
Ingress

Daemon Set

It is used to instantiate pod in every available node.
Min and max node created using deman set is 1.
kubectl get ds

Job & CronJob

Job is the resource which runs the task and monitor it to complete.
Cron job is the resource which runs the task and repeat it on defined schedule.

ConfigMap

this is configurations required for service and we can use in service as volume mounts.
its stored in etcd i.e. as key and value pair

Services

We call it as Service and not Load Balancer
Service = Network Load Balancer
Ingress = Application Load Balancer

kubectl create svc -h

*Ingress *
Ingress is a way for enabling traffic. Also helps in routing.
Ingress means a rule. It is an API object.
Ingress controller is exposed with the load balancer.

Path Based
Name Based
TLS Based

What is Namespace,troubleshoot PODs,ReplicationController,ReplicaSet & Deployement by Harish Kumar G

Harish Kumar G — Wed, 18 Oct 2023 04:04:31 +0000

Namespace:-

Namespace is used to Structuralize the resources of the Clustered Horizontally. eg.. ram, diskspace, cpu etc
Namespaces was introduced to overcome 2 problems, 1.To avoid problems while using the shared resources by diff applications 2.To restrict access over resources
Any namespace will be classified under one of the below category, System - Created by Kubernetes Public - Common resources Default - When no namespace is provided Admin - For admin roles
When namespace is deleted, all respective pods will get deleted

Accessing resources:

resources can be accessed either via command or config file.
Create- create/ create -f yaml
Read- get/ get -f yaml
Update- edit / apply -f yaml
Delete- delete / delete -f yaml

ReplicationController and Replica Set

Replicationcontroller is used to instantiate multiple pods and control the running pods.
Replica Set is the updated version of ReplicationController.

Debugging/Troubleshooting strategies

Logs
attach
Exec
Port forward
copy
auth

Deployment

Deployment is used to instantiate pod and control the running pods using help of Replica Set and pod.

What is Pod - day 1 - Harish Kumar G

Harish Kumar G — Mon, 16 Oct 2023 11:50:40 +0000

What is POD:

POD is the smallest execution unit in kubernetes.
POD can have one or more container applications.
POD is ephemeral b nature.
IF a pod fails, kubernetes can automatically create new pod to
continue operations.
every container in pod will have same address but different port numbers.
LifeCycle of POD: Pending, Running, Succeeded, Failed, Unknown
No same POD can be created again, similar pod can be created but not same.

Assignment -1 from Harish Kumar G

Harish Kumar G — Mon, 16 Oct 2023 07:21:12 +0000

What is Kubernetes?

Kubernetes is a open source container orchestrator, developed by google and handed over to cncf in 2014.
Helps in achieving Highly available and scalable of services.

Why Do we need Kubernetes? Explain in 10 lines

It is the only leading container orchestrator and actively growing open source tool available.
Simplifies container management on multilpe hosts
Easy for enterprises apps to be highly scalable
Automates deployment
Runs application with better stability
Easy to roll out new software versions
Kubernetes is portable and flexible
It has a large community

How Kubernetes Works?

Kubernetes follows master slave architecture, where master node overseas the entire cluster.
Master effectively manages the scheduling, allocating the resources, monitoring the Health of the infrastructure.

Kubernetes Architectecture. Explain each component with 1 oneline.

Kubernetes follows master slave architecture, where master node overseas the entire cluster.

Master : Overseas the entire cluster. composed of 4 entities.
* API server: API server is the front end of kubernetes
control panel
* Cluster store: Consistent and highly-available key value

store used as Kubernetes' backing store for all cluster
data.
* controller manager: manages different controller like Node
controller, job controller, Health status , this is a
continuous monitoring.
* Scheduler: watches for newly created Pods with no assigned
node, and selects a node for them to run on.

Worker Node:
* kubelet : An agent that runs on each node in the cluster.
It makes sure that containers are running in a Pod.
* Container run-time: A fundamental component that empowers
Kubernetes to run containers effectively. It is responsible
for managing the execution and lifecycle of containers
within the Kubernetes environment. now the default
container run-time is containerd, docker is deprecated.
* Kube-proxy: kube-proxy is a network proxy that runs on each
node in your cluster