Operations & DevOps Systems Engineering Knowledge Map Cheat Sheet

The core mandate of Operations & Site Reliability Engineering (SRE): ensure digital services are deliverable, observable, resilient, and continuously optimized for reliability, security, and cost efficiency.

Use this knowledge map to navigate core infrastructure domains and locate command-line workflows. Tool references are industry-standard examples to be selected based on organizational scale and architecture.

01 · Foundational Infrastructure

Systems & Networks

Ensure operating systems run stably and network traffic reliably reaches target services.

Linux Administration: File permissions (POSIX), user/group management, processes, package managers (apt/dnf), systemd service units, and crontab schedulers.
Resource Diagnostics: CPU, memory, disk I/O, and throughput; top, htop, free -m, df -h, iostat -xz 1, and vmstat.
Networking Foundations: TCP/IP stack, subnets, CIDR routing, DNS resolution, HTTP/TLS handshakes, NAT tables, and firewall rules (iptables/nftables).
Connectivity Troubleshooting: ip addr & ip route for addressing, ss -tulpn for open sockets, dig for DNS propagation, curl -Iv for HTTP tracing, and tcpdump for packet capture.

Explore: Linux Commands · Network Protocols & Ports

02 · Service Runtimes & State

Services & Data

Manage service dependencies, connection pools, stateful storage, and configurations.

Reverse Proxies & Ingress: Nginx / HAProxy; HTTP routing, reverse proxying, TLS termination, SSL certificates, load balancing algorithms, and rate limiting.
Relational Databases: MySQL / PostgreSQL; connection pooling, ACID transactions, B-Tree indexes, slow query logs, read replicas, and WAL point-in-time recovery.
Distributed Caching: Redis / Memcached; cache hit ratios, TTL expirations, eviction policies (LRU/LFU), memory ceilings, and persistence options (RDB/AOF).
Message Brokers: Kafka / RabbitMQ; producers, consumer groups, partition lags, retry queues, idempotency keys, and dead-letter queues (DLQ).

Explore: MySQL Commands · Nginx Configuration

03 · Operational Feedback

Observability

Detect user-facing degradation instantly and correlate metrics, logs, and distributed traces.

Metrics & Telemetry: Prometheus / VictoriaMetrics for time-series metric ingestion; focus on Golden Signals: Latency, Traffic, Errors, and Saturation (USE/RED methods).
Logs & Distributed Tracing: Structured JSON logging; Loki / Elasticsearch / OpenSearch for aggregation; OpenTelemetry (OTel) for standardized vendor-neutral distributed trace collection.
Dashboards & Alerting: Grafana for unified visualization; configure Alertmanager with deduplication, grouping, inhibition rules, route trees, and runbook links.
Reliability Objectives: SLI (Service Level Indicator), SLO (Service Level Objective), and Error Budgets governing deployment velocities vs. stability investments.

Reference: Prometheus · Grafana · OpenTelemetry

04 · Delivery Engineering

Deployment & Automation

Transform manual configurations into reproducible, auditable, and automated delivery pipelines.

Version Control & Artifacts: Git for code and configuration; semantic versioning; push container images to immutable registries (Harbor, AWS ECR).
CI/CD Pipelines: GitHub Actions, GitLab CI, Jenkins; automated linting, unit testing, image builds, security scanning (Trivy), and deployment validation.
Infrastructure as Code (IaC): Terraform / OpenTofu for declaring cloud topology; Ansible for configuration drift management and OS baseline hardening.
Release Strategies: Rolling updates, Blue-Green deployments, and Canary rollouts paired with synthetic health checks and automated rollback triggers.

Explore: Git Cheat Sheet · Shell Scripting

05 · Modern Infrastructure

Cloud & Containers

Decouple application runtimes from physical hardware via immutable virtualization and orchestration.

Container Runtimes: Docker / containerd; multi-stage Dockerfile builds, layer caching, minimal non-root base images (Alpine/Distroless), and cgroup isolation.
Kubernetes Orchestration: Pods, Deployments, Services, ConfigMaps, Secrets, Ingress, and Horizontal Pod Autoscalers (HPA).
Cluster Networking & Storage: CNI plugins (Cilium / Calico), CoreDNS service discovery, PersistentVolumes (PV/PVC), and CSI storage drivers.
Cloud Architecture: VPC subnets, Security Groups, IAM least-privilege roles, Managed K8s (EKS/GKE), object storage (S3), and CloudFront/CDN caching.

Explore: Docker Compose · Kubernetes Reference

06 · Resilience & Continuity

Storage & Disaster Recovery

Guarantee data durability, high availability, and business continuity during infrastructure failures.

Storage Architectures: Block storage (EBS/SAN), File storage (NFS/EFS), Object storage (S3/MinIO); filesystem types (ext4, XFS, ZFS).
Backup Paradigms (3-2-1 Rule): Full, incremental, and differential backups; enforce retention policies, immutable snapshots, and offsite cross-region replication.
Recovery Targets: RPO (Recovery Point Objective: tolerable data loss window) and RTO (Recovery Time Objective: target restoration duration); validate through recurring drill simulations.
High Availability: Multi-AZ deployments, active-passive failover, cross-region replication, and automated health checking. Note: RAID and replication do not replace independent point-in-time backups.

Operations: Disk & File Transfers · MySQL Backups

07 · Security & Governance

Security & Governance

Enforce zero-trust access controls, compliance standards, and immutable operational audit trails.

IAM & Privileged Access: Least-privilege access, ed25519 SSH keys, hardware MFA, credential rotation, and centralized bastion jumping with session recording (Teleport).
System & Network Hardening: CIS Benchmark compliance, kernel sysctl tuning, security patching, TLS 1.3 enforcement, and automated dependency CVE scanning.
Standard Operating Procedures (SOP): Formalized change approval workflows, runbooks with explicit rollback triggers, and CMDB asset inventory.
Compliance & Audit: Centralized SIEM audit logging, tamper-proof logs, and adherence to security baselines (SOC 2, ISO 27001, GDPR).

Explore: Network Security Protocols · Cryptography & Encryption

08 · Continuous Improvement

Incident Response & Performance

Restore production availability first, isolate root causes second, and verify optimizations with data.

Incident Command: Triage severity (P0/P1/P2), designate Incident Commander, inspect recent deployments; execute mitigation runbooks (rate limit, scale out, traffic diversion, rollback).
Post-Mortem & Review: Blameless post-mortems correlating metrics, logs, traces, and deployment timelines; assign actionable remediation tickets with owners and deadlines.
Performance Profiling: Pinpoint bottlenecks from user-perceived p99 latency down to CPU throttling, memory leaks, disk queue saturation, or slow database locks; use perf, bcc-tools, and eBPF.
Capacity Planning: Establish performance baselines, conduct synthetic load testing (k6, Locust), evaluate throughput saturation knees, and tune autoscaling thresholds.

Diagnostics: Linux Diagnostics · Network Protocols

Standard Operational Workflows

Step outcomes strictly govern progression; anomalous releases trigger automated rollbacks; incident closures mandate blameless retrospectives.

Deployment Workflow

Commit & PR ReviewCode, configuration, and change tickets approved
Automated Test & BuildLinters pass, unit tests succeed, container images built
Artifact IngestionImage signed, vulnerability-scanned, and pushed to registry
Staged RolloutCanary / Blue-Green deployment with health check probes
Validation & Gatep99 latency and error rates monitored; promote or rollback

Establish automated rollback thresholds before initiating deployments; database schema migrations must be backward-compatible.

Incident Management Workflow

Triage & ScopeDetermine business impact, assign severity level and Incident Commander
Mitigate & StabilizeExecute emergency runbooks: rollback release, divert traffic, shed load
Verify Service HealthConfirm synthetic user journeys and key metrics recover to baseline
Root Cause AnalysisPreserve ephemeral logs, build timeline of events and trigger conditions
Blameless RetrospectiveFormulate actionable engineering fixes with clear assignees and due dates

Service recovery always takes precedence over root-cause investigation; preserve ephemeral error traces before restarting instances.

DevOps Learning Roadmap

Systems & NetworkingLinux server administration, TCP/IP debugging, shell scripting
Service DeliveryWeb proxies (Nginx), databases (PostgreSQL/MySQL), cache clusters
Observability & RecoveryPrometheus/Grafana telemetry, alerting runbooks, disaster recovery drills
CI/CD & AutomationGit workflows, containerization (Docker), automated deployment pipelines
Cloud & Reliability EngineeringKubernetes orchestration, Terraform IaC, SLO management, capacity tuning

Capstone Project: Deploy an end-to-end containerized web application with TLS termination, Prometheus monitoring, automated CI/CD deployment, and an executed rollback drill.