Introduction to k8s

It is an open source container-orchestration system for automating software application deployments, scaling and management.

Deployment Object: A deployment object is an application which is being deployed to be utilised as a service.

Ingress Object: An API object that primarily manages external access to Service from the cluster, typically HTTP. It can also do Load Balancing, SSL Termination and name-based virtual hosting.

Stateful Set: A workload API object used to manage stateful applications.

Node: A worker machine physical or virtual in cluster, managed by Master.

Pod: A k8s abstraction to represent a group of application containers and some shared resources among them like Storage Volume, cluster IP address, information about running of containers etc.

Controller Manager: A daemon that embeds the core control loops shipped with k8s.

Deployment Controller: It makes actual changes to the deployment state to the desired state at a controlled rate. It creates ReplicaSet, stops a bad rollout, stops scaling up the bad ReplicaSet, and in general manages them.

Replica Set: Maintains a stable set of pods always running, essentially guaranteeing availability of a specified number of identical pods.

Service Object: An abstraction to expose set of pods running application as a network service. k8s gives pods their own IP addresses and a single DNS name for the set of pods, and can also load balance between them.

Exposing Service Deployed: Any Pod in a cluster is accessible internally, and the Cluster can be exposed to external requests via REST APIs by setting an IP and DNS name.