What is HLD ?
by Alli Darabi
High-Level Design (HLD) in DevOps: A Comprehensive Guide
As a
DevOps Engineer, understanding High-Level Design (HLD) is crucial for
architecting scalable, secure, and efficient systems. HLD serves as a bridge
between business requirements and Low-Level Design (LLD), providing a bigpicture view of system architecture.
📌 1. What is High-Level Design (HLD)?
HLD is a
conceptual and architectural representation of a system. It outlines the major
components, integrations, and infrastructure without going into deep
technical details.
including:
What components make up the system?
How do these components interact?
What technologies and services are involved?
What are the system’s scalability, security, and reliability considerations?
excluding:
Detailed configuration files or scripts
What is HLD ?
1
Specific implementation details (e.g., exact Kubernetes manifests)
Code-level logic (covered in Low-Level Design, LLD)
📌 2. Key Components of HLD
Every HLD document typically includes these sections:
🖼️ 2.1 System Overview
What?
A high-level summary of the system, including its business objectives and
functional goals.
Defines what problem the system solves.
Example:
"A cloud-based logging platform that collects, processes, and visualizes logs
from multiple microservices using OpenSearch, Logstash, and Filebeat."
⚙️ 2.2 Architecture Diagram
What?
A visual representation of system components and their interactions.
Common Elements in an HLD Diagram
Compute Resources (Kubernetes, VMs, Serverless)
Networking (Load balancers, Firewalls, VPNs)
Storage (Databases, Object Storage, Caching)
Security (IAM, Secrets Management)
Observability (Monitoring, Logging, Alerting)
Example
What is HLD ?
2
A microservices architecture diagram with:
An API Gateway handling requests
Multiple microservices running on Kubernetes
A CI/CD pipeline automating deployments
ElasticSearch & Kibana for logging and monitoring
💾 2.3 Infrastructure Architecture
What?
Defines the infrastructure components that support the application.
Key Aspects
✅ Cloud vs. On-Prem
AWS, Azure, GCP
Bare Metal or Hybrid Cloud
✅ Compute Resources
Kubernetes (EKS, AKS, GKE)
Virtual Machines (EC2, Azure VMs)
Serverless (AWS Lambda, Google Cloud Functions)
✅ Networking & Load Balancing
AWS ALB/NLB
HAProxy, Nginx, Envoy
✅ Storage & Databases
SQL: PostgreSQL, MySQL, MS SQL
NoSQL: MongoDB, DynamoDB, Cassandra
Caching: Redis, Memcached
✅ Container Orchestration
Docker & Kubernetes
What is HLD ?
3
Helm for managing configurations
🚀 2.4 CI/CD Pipeline
What?
Defines how code moves from development to production.
Pipeline Stages
1️⃣ Code Commit → GitHub/GitLab
2️⃣ Build → Docker, Maven
3️⃣ Testing → Unit, Integration, Load Testing
4️⃣ Artifact Storage → Nexus, Artifactory
5️⃣ Deployment → Kubernetes (ArgoCD, Helm)
6️⃣ Monitoring & Rollback → Prometheus, Grafana
Example Pipeline
GitHub → Jenkins → Docker Build → Kubernetes Deployment → Prometheus
Alerting
🔍 2.5 Monitoring & Observability
What?
How do we ensure system health, performance, and security?
Key Metrics
✅ Infrastructure Monitoring: CPU, Memory, Disk Usage
✅ Application Monitoring: Request Latency, Error Rates
✅ Logging & Tracing: Logstash, OpenTelemetry
✅ Alerting: PagerDuty, OpsGenie
What is HLD ?
4
🔐 2.6 Security & Compliance
What?
Ensuring security at every level of the system.
Key Aspects
✅ Authentication & Authorization
IAM Roles, OAuth, RBAC, ABAC
✅ Data Security
Encryption (TLS, AES-256)
Secret Management (AWS Secrets Manager, HashiCorp Vault)
✅ Compliance & Auditing
GDPR, SOC2, ISO 27001
📈 2.7 Scalability & Availability
What?
Defines how the system scales to handle increased load.
Key Concepts
✅ Auto-Scaling: Horizontal & Vertical Scaling
✅ Load Balancing: Traffic Distribution
✅ Failover & Disaster Recovery: Multi-Region Replication
📌 5. Conclusion
HLD provides a big-picture view of your system.
It helps architects, DevOps engineers, and stakeholders align on design
decisions.
Understanding infrastructure, CI/CD, observability, security, and scaling
is essential.
What is HLD ?
5
Keep asking "Why are we making this change?" to ensure meaningful
updates.
What is HLD ?
6