Architecture Flashcards
What is a node?
Physical or virtual machine on which kubernetes is installed. It is also the worker machine where containers will be launched by kubernetes. Nodes were also known as minions in the past
what is a cluster?
Set of nodes grouped together. For redundancy purpose and load sharing.
What is the master node?
Another node where kubernetes is running within the cluster. Master node manages the worker nodes in the cluster. It is responsible for the actual orchestration of the cluster.
List components that are installed when we install Kubernetes?
- API Server
- etcd
- Scheduler
- Controller
- Container runtime
- Kubelet
What is API server in Kubernetes?
Acts as the front end for Kubernetes
Users, management devices, All Talk to the API server
What is etcd or etcd key store in Kubernetes?
Distributed reliable key value store used by Kubernetes to store all data used to manage the cluster.
For eg. if there are multiple nodes and multiple masters in a cluster, etcd stores all that information on all the nodes in the cluster in a distributed manner.
etcd is responsible for implementing locks within the cluster to ensure that there are no conflicts between the masters.
What is scheduler in Kubernetes?
Distributing work or containers across multiple nodes
Looks for newly created containers and assigns them to nodes.
What are controllers in Kubernetes?
Controllers are the brain behind orchestration. Notices and responds when containers or endpoints go down. They decide to bring up new containers in such scenarios.
What is Container runtime in kubernetes?
Underlying softwares that is used to run the containers. For eg. Docker
What is the kubelet component in Kubernetes
Kubelet is the agent that runs on each node in the cluster. Agents responsible for making sure the containers are running on the nodes as expected
What makes the master node/server a master? What classifies it as master?
It has the kube-apiserver. The worker node has the kubelet agent that communicates with the kube-apiserver
What is the function of the kubelet agent in the worker node?
To communicate with the kube-apiserver in the master node and interact with master to provide the health info of all worker nodes and carry out the actions suggested by master on the worker node
Where are all the information gathered from worker nodes stored?
Stored in the master node in a key-value store (etcd framework)
what is kubectl?
kube control tool is a cmd line utility tool used to deploy and manage applications on a Kubernetes cluster
kubectl run hello-minikube
Deploy an application on a cluster
Deploys a docker container by creating a pod. First creates a pod and deploys a docker container using the image of hello-minikube
