Welcome! In this guide, I‘ve put together some key questions and detailed answers to help you master VMware NSX for career growth or certification.
As companies virtualize infrastructures, network virtualization with VMware NSX becomes critical for agility and security. That’s why over 82% of the Fortune 100 have now adopted NSX, validating its position as the future of modern IT.
With surging NSX adoption, networking pros with these skills are in high demand. Let’s get you ready to ace those interviews! I’ll explain key NSX concepts first then dig deeper across components, services, management and more.
Why VMware NSX Matters
Before diving into the product, it’s worth understanding why network virtualization matters in the first place.
In traditional networks, the control plane directing traffic relies on physical hardware. This restricts configurability, automation and scaling. It also limits security controls to the network perimeter.
NSX transforms this by decoupling the control and data planes, so network logic moves to software. This brings powerful advantages:
1. Centralized Control and Visibility
- Manage networking across sites from a single pane of glass
- Consistent configs and monitoring improves uptime
- Troubleshoot faster with end-to-end visibility
2. Improved Agility and Efficiency
- Spin up logical networks instantly without physical changes
- Hypervisor-embedded security scales inline with VMs
- Automate everything through APIs for efficiency
3. Enhanced Security Posture
- Microsegment environments based on app/VM attributes
- East-west firewalling limits lateral attacker movement
- Introspect traffic at a granular layer for faster response
Clearly, NSX abilities around flexibility, operations, and security are forcing adoption. Now let’s explore that value through key concepts and capabilities.
NSX Basics: Core Concepts
Q1. What is decoupling?
Decoupling software from physical hardware enhances flexibility. The NSX control plane provides a virtual network model for centralized management while data continues flowing through underlying physical network elements.
Q2. What comprises the control plane?
The NSX control plane consists of three key elements:
NSX Manager: Single management pane and API endpoint for administrative tasks
NSX Controller Cluster: Maintains virtual network state and disseminates configs
vSphere Hypervisors: Host-level virtualization, distributed routing, and security enforcement
Q3. What is the data plane then?
This underlay physical infrastructure transports actual application data between endpoints based on control plane directives:
- Network Hardware: Switches, routers, firewalls
- Cabling/VLANS: Forconnectivity
- Hypervisor VSwitches: Enable virtual machine traffic
Q4. What about the management plane?
The management plane primarily includes the NSX Manager appliance, which serves as an aggregation point for monitoring, automation, and operational sanity. It coordinates directly with both the data plane and control plane.
Q5. Can you summarize logical switching?
One key NSX feature! Logical switching creates virtual L2 broadcast domains and L3 subnets to logically interconnect VMs.
This enables:
- Application Segmentation: Isolate app tiers into separate networks
- Multi-Tenancy: Split dev vs production into their own L2/L3 contexts
- Portability: VM connectivity persist when migrating across hosts
And unlike VLANs which max out at 4K segments, NSX can create thousands of logical network overlays as needed!
Q6. How do these logical networks connect physically?
The NSX edge services gateway (ESG) links logical segments to physical infrastructure. Just like a physical router connects VLANs, the ESG interfaces logical switching domains with external physical environments.
That connectivity allows VMs within NSX to access resources on your corp network or data center interconnects.
Q7. Okay, but how does traffic move between logical networks?
Now that VMs can live in different logical networks, you need routing capabilities for visibility and appropriate security controls between these virtual segments.
That‘s where NSX logical routing comes in!
NSX logical routers establish east-west connectivity between discrete virtual subnets, interconnecting your application tiers, dev environments, etc. for infrastructure-wide communication.
Q8. Can you define east-west vs north-south traffic?
East-west traffic stays within the virtualized data center, moving laterally across logical NSX subnets.
North-south traffic ingresses or egresses externally from the virtual infrastructure out to physical networks or endpoints.
Think virtual machine to virtual machine = east-west.
Virtual machine to corporate HQ = north-south.
Q9. How does NSX improve security?
NSX secures environments through logical firewalling mechanisms applied at the hypervisor kernel level.
The NSX distributed firewall attaches stateful L2-L4 rulesets directly to each virtual machine similar to an IPSec policy attaching to a physical endpoint. Distributed firewall policies filter lateral east-west traffic between network segments.
For north-south filtering, the NSX edge firewall provides robust ACLs and application inspection on gateways connecting virtual to physical.
Advanced security groups can also apply additional IPS/IDS capabilities through NSX!
Q10. What about load balancing?
The integrated NSX load balancer distributes flows across application tiers based on round robin algorithms or resource consumption metrics for performance efficiency and high availability, without requiring external appliances.
Admins can map pools of virtual machines to a virtual IP and distribute incoming requests across those pool members. NSX manages the load monitoring and health checks behind the scenes!
Q11. How does the NSX service composer help?
To ease management overhead for large dynamic environments, the NSX service composer allows admins to define reusable "security groups" with attached policies.
As an example, you may create a security group for a multi-tiered web application assigning these services:
- Distributed firewall rules to filter traffic from app tier 1 to the database tier
- An intrusion detection system to monitor lateral connections for threats
- An endpoint anti-virus profile to secure the virtual machines themselves
Any new virtual machines added to that group automatically and instantly inherit those network and security services!
This prevents having to manually tie configurations to assets as your environment scales up.
NSX Architecture Components
Now that we‘ve covered some key concepts, next let‘s do a deeper dive into foundational NSX components and architecture.
Q12. What exactly is the NSX manager appliance?
The NSX manager provides the administrative access point for building, monitoring and securing NSX environments. Features include:
- Centralized configuration dashboard and API endpoint
- Translation of logical network constructs to underlying vSphere infrastructure
- Integration with vCenter, cloud platforms, and orchestration tools
- Performance monitoring, logging/auditing, backup and cluster coordination
The manager gets deployed as a virtual appliance onto an initial ESXi host, then integrates with vCenter Server for environment-wide visibility.
Q13. What comprises the NSX controller cluster?
NSX controllers are the secret sauce, acting as the brains managing device and topology information as well as distributing security and connectivity instructions.
The controller architecture creates the logical network overlay, translating virtual constructs to physical components. Key functions:
- Maintains universal logical network state
- Pushes routing/security configs to hypervisors
- Manages overlay address assignments and mappings
- Runs the control VMK interface for packet-in requests
For resiliency, deploy NSX controllers in a 3+ node cluster, allowing seamless failover if a controller goes offline.
Q14. Could you define VXLAN and its role?
VXLAN provides the tunneling mechanism that actually encapsulates and transports logical network traffic over the physical network fabric between hypervisors.
It tunnels Layer 2 packets within outer Layer 3 UDP/IP headers to form overlay logical networks across L3 boundaries:
This VXLAN segment ID defines unique virtual network domains to isolate connectivity and traffic.
Hypervisors terminate VXLAN tunnels at their virtual tunnel endpoints (VTEPs) to forward encapsulated traffic between logical endpoints.
Q15. And what are those VTEPs exactly?
VTEP stands for VXLAN tunnel endpoint, basically the hypervisor source and destination for logical network communications.
Each ESXi host serves as a VTEP to terminate VXLAN tunnels and forward traffic for virtual machines on that host communicating across logical switches.
The VTEP maps inner VM MAC addresses and Layer 2 segments to outer tunnel IP transports between hypervisors based on the VXLAN network identifier.
Admins configure VTEP VMkernels on each host to handle this tunnel termination and mapping process.
Q16. Okay, makes sense! What about transport zones though?
While logical switches can span multiple ESXi hosts, eventually physical network constraints like latency or firewall policies may dictate segmentation.
This is where transport zones come into play – defining logical boundary scopes for hosts participating as VXLAN tunnel endpoints.
Transport zones act as contention domains, grouping hosts appropriate for interconnectivity based on physical underlay characteristics or infrastructure dependencies.
This allows limiting lag or fitting regulatory policies by preventing universal logical network distribution where unwanted.
Q17. How do universal transport zones differ?
A universal transport zone can expand a logical network across multiple NSX deployments spanning different vCenter Server infrastructures!
This supports seamless workload mobility across otherwise isolated vSphere environments.
Only NSX managers registered as universal transport zone members can participate in cross-vCenter logical networks. Use cases include large multi-region deployments or dynamic cloud bursting.
Q18. Could you summarize the NSX edge services gateway?
The NSX edge services gateway (ESG) enables routing connectivity for services extending virtual networks to a physical environment.
Key features:
- Firewalling for ingress/egress security policies
- Routing with dynamic protocols (OSPF/BGP)
- VPN for remote connectivity
- Load balancing across application services
- NAT for IP address translation
- DHCP for virtual IP assignments
- High availability with active/passive failover
The edge connects virtual machines to physical network and security infrastructure like next-gen firewalls. You can tune NSX edge appliances by size for varying performance demands.
Q19. How does the NSX firewall architecture work?
As mentioned when discussing concepts earlier, the NSX distributed firewall and NSX edge firewall combine to enable virtual machine attribute-based rules as well as physical perimeter enforcement.
NSX Distributed Firewall
The distributed firewall embeds stateful L2-L4 firewalling directly within the ESXi hypervisor kernel, using the VSIP module for high-speed filtering.
This kernel-level local enforcement enables microsegmentation based on vCenter objects like VM name or network tags:
NSX Edge Firewall
The NSX edge firewall offers a robust L3-L7 stateful perimeter gateway firewall for securing north-south traffic:
Using both in concert provides full application-level filtering and threat prevention!
Q20. What are some key NSX firewall capabilities?
Advanced NSX distributed firewall features include:
- Building rulesets based on vCenter primitives like VM names, OS types, Active Directory groups or vLANs
- Dynamic insertion/updates without disruption as new VMs launch
- Lateral east-west microsegmentation for application security tiers
- IDS/IPS integration via partner services for advanced threat detection
While NSX edge firewalling offers:
- Robust L3-L4 stateful rulesets
- Application layer whitelisting and blacklisting
- Secure web gateway functionality
- SSL inspection for encrypted traffic
- Integration with perimeter security appliances
And crucially, both policy sets integrate with APIs, automation tools like Ansible/Puppet/Chef and orchestrators like vRA!
NSX Operations, Monitoring and Troubleshooting
Now that we‘ve outlined core components, next let‘s explore some common operational, monitoring and management capabilities for administering NSX environments.
Q21. How does VM mobility work given NSX environments?
A key NSX benefit is keeping virtual machine connectivity persistent, even as workloads migrate across the environment!
Using logical switching and centralized control, VMs can move between hosts while retaining network profiles and addresses.
No matter the underlying physical change, as long as destination hosts map to the same logical switch the VM will reconnect to the same subnets/security policies.
Prepare host clusters for VM mobility by adding hosts to universal transport zones and enabling both DRS and vMotion.
Q22. What mechanisms help troubleshoot NSX?
NSX offers several tools to monitor connectivity and pinpoint issues:
Traceflow: Simulates a packet forwarding path between defined VMs, highlighting policy blocks
Port Connection Tool: Validates connectivity between VTEP interfaces
IPFIX: Centralized flow metadata reporting for visibility
Syslog: Aggregate logging with vRealize and partner monitors
Additionally the NSX manager provides an end-to-end topology view with health statuses for controllers, hosts and tunnels. Granular dashboards track performance KPIs.
Integrating NSX with ecosystem tools expands capabilities further!
Q23. What about backing up and restoring NSX?
Proper NSX backups help restore functionality after outages. Admins should backup:
- NSX manager configuration
- NSX controller state
- Host historical status for VIBs and tunnels
- Logical router and distributed firewall rulesets
- Edge configurations
Use native NSX backup or vSphere Data Protection for this. Test by restoring configs to a secondary NSX environment to validate completeness.
Disaster recovery requires redeploying NSX appliances then carefully restoring configurations top down in terms of dependency. Document DR procedures as environments scale in complexity!
Q24. What options exist for NSX monitoring?
VMware offers the native NSX dashboard and reporting capabilities for operational visibility:
Additionally, the Guest Introspection framework captures deep application performance metrics from within virtual machines for troubleshooting.
For advanced analytics, logging and performance managements, explore tools like:
- vRealize Network Insight: VMware network analytics platform
- vRealize Operations: Infrastructure monitoring with NSX packs
- Sentinel: Performance monitoring with visibility into East-West traffic flows
Finally, don‘t forget SNMP monitoring via existing platforms to track VM networking!
Wrapping Up
That concludes our NSX primer! I aimed to provide strong NSX interview preparation across critical concepts, architecture overview, operations, security capabilities and more – equipping you to master VMware network virtualization technologies for career and certification success.
Let me know if any other NSX questions come up! I‘m always happy to chat further about these tools and recent innovations in the space.
