Kubernetes Architecure
Kubernetes Basics Modules
Kubernetes cluster
Node
virtual or physical machine
control plane
etcd
holds the current status of any k8s component
Main Kubernetes Components
Pod
- Smallest unit in Kubernetes.
- Abstraction over container.
- Usually 1 Application per Pod
- Each Pod gets its own IP address
- New IP address on re-creation（Pods are ephemeral）
- Internal service(service-name:ip)
- External service(node-ip:port)
Service
- communication
- Permanent IP address
- Lifecycle of Pod and Service not connected
Ingress
- route traffice into cluster
- 绑定域名和服务
ConfigMap
- external configuration of your application
- for non-confidential data only
Secret
- external configuration of your application
- for secret data
Volume
- used for darta persistence
Deployment
- Define blueprint for Pods
- Abstraction of Pods
- for stateless apps
- replication
StatefulSet
- for statefull apps or databases
- DB are often hosted outside of Kubernetes cluster
- replication