Kubernetes Terminology
Node
Master Node
Worker Node/ Compute Node
Resource
Controller
Label
Namespace
Openshift Terminology
Infra Node
Console
Project
Kubernetes & Openshift Architecture
Kubernetes Resource Types
Pods (po)
- Represent a collection of containers that share resources, such as IP address and persistent storage volumes.
- It is the basic unit of work for kubernetes.
Services (svc)
- Define a single IP/port combination that provides access to a pool of pods.
- By default, services connect clients to pods in a round-robin fashion.
Replication Controllers (rc)
- A kubernetes resources that defines how pods are replicated (horizontally scaled) into different nodes.
- Replication controllers are a basic kubernetes service to provide high availability for pods and containers.
Persistent Volumes (pv)
- Define storage areas to be used by Kubernetes pods.
Persistent Volume Claims (pvc)
- Represent a request for storage by a pod.
- PVCs links a PV to a pod so it containers can make use of it, usually by mounting the storage into the container's file system.
ConfigMaps (cm) & Secrets
- Contains a set of keys and values that can be used by other resources.
- ConfigMaps & Secerets are usually used to centralize configuration values used by several resources.
- Secreats differ from ConfigMaps in the secret's values are always encoded (not encrypted) and their access is restricted to fewer authorised users.
Openshift Resource Types
Deployment config (dc)
- Represents the set of containers included in a pod, and the deployment strategies to be used.
- A dc also provides a basic but extensible continuous delivery workflow.
Build config (bc)
- Defines a process to be executed in the Openshift project.
- Used by the Openshift Source-to-image (S2I) feature to build a container image from application source code stored in a Git repository.
- A bc works together with a dc to provide a basic but extensible continuous integration and continuous delivery workflows.
Routes
- Represent a DNS host name recognised by the OpenShift router as an ingress point for applications and microservices.
