Cloud Fundamentals
Cloud Fundamentals is the vocabulary and architecture domain of JNCIA-Cloud. The exam tests whether you can place a workload in the right service and deployment model, distinguish virtualization from cloud-native packaging, and recognize where Juniper’s virtual and containerized products fit.
Service and deployment models
- IaaS gives you compute, storage, and networking plus control of the guest OS. PaaS manages the runtime and platform, so you deploy code, not the OS. SaaS delivers a finished application.
- Public, private, hybrid, and multicloud describe ownership and placement, not whether virtualization is used.
- NIST-style cloud traits: on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. A private cloud still needs these; a plain on-premises VM farm is not automatically a private cloud.
Virtualization and cloud-native
A Type-1 hypervisor runs directly on hardware and hosts VMs. Containers share the host kernel and package the application with its dependencies, so they are lighter than VMs but less isolated by default. NFV replaces appliance functions with VNFs or CNFs; SDN separates the control plane from the data plane and centralizes control.
Juniper cloud portfolio
Juniper’s cloud portfolio includes vMX (virtual MX router), vSRX (virtual SRX firewall), cSRX (containerized SRX), and Cloud-Native Router for Kubernetes-oriented routing. Contrail Networking provides SDN overlay and network virtualization, while Apstra provides intent-based data center fabric management.
Worked example
A team must run a custom Java application on a specific OS patch level and manage its own database. Choose IaaS, because the team needs guest-OS control. If the team only wanted to deploy code into a managed runtime, PaaS would fit. If it only consumed a hosted email service, SaaS would fit. The decision follows the control boundary, not the word “cloud.”
Traps that cost marks
Do not equate SDN with NFV: SDN changes control-plane architecture; NFV virtualizes network functions. Do not say containers require a hypervisor per container. Do not confuse vSRX (VM) with cSRX (container). Do not call every virtualized data center a private cloud without self-service, pooling, and elasticity.
Key points
- IaaS = OS control; PaaS = runtime managed; SaaS = application consumed.
- Private cloud requires cloud characteristics, not just virtualization.
- SDN separates control and data planes; NFV virtualizes network functions.
- vMX is a virtual router; vSRX is a virtual firewall; cSRX is containerized.
- Contrail is SDN/network virtualization; Apstra is intent-based fabric management.