Your 90-Day DevOps/SRE Study Plan

A structured 90-day plan to transform you from "preparing" to "interview-ready." Adjust based on your current level and target companies.

Assessment: Where Are You Starting?

Before diving in, honestly assess your current level:

Area	Beginner	Intermediate	Advanced
Linux	Basic commands	Process/memory mgmt	Kernel tuning
Networking	TCP vs UDP	DNS, load balancing	BGP, network design
CI/CD	Used Jenkins/GHA	Built pipelines	Designed for scale
Containers	Docker basics	K8s deployments	Operators, custom controllers
Monitoring	Used Grafana	Built dashboards	Designed observability
Coding	Bash scripts	Python/Go fluent	Distributed systems

Phase 1: Foundations (Days 1-30)

Goal: Solidify fundamentals that appear in EVERY interview

Week 1-2: Linux Deep Dive

• Process lifecycle (fork, exec, zombie processes)
• Memory management (virtual memory, OOM killer)
• File systems (inodes, permissions, types)
• System calls (strace, ltrace)
• Practice: Set up a Linux VM, break it, fix it

Week 3-4: Networking Essentials

• OSI model (focus on layers 3, 4, 7)
• TCP handshake, congestion control
• DNS resolution, caching, TTL
• Load balancing algorithms
• Practice: tcpdump, Wireshark packet analysis

Daily routine (2-3 hours):

30 min: Read documentation/books
60 min: Hands-on lab practice
30 min: Review and note-taking
30 min: Mock troubleshooting scenarios

Phase 2: Tools and Systems (Days 31-60)

Goal: Master the tools you'll discuss in interviews

Week 5-6: CI/CD and IaC

• Git advanced (rebase, cherry-pick, bisect)
• GitHub Actions / GitLab CI deep dive
• Terraform state, modules, workspaces
• Ansible playbooks and roles
• Practice: Build a complete CI/CD pipeline

Week 7-8: Containers and Orchestration

• Docker internals (namespaces, cgroups)
• Kubernetes architecture deep dive
• Pod lifecycle, scheduling, affinity
• Services, Ingress, NetworkPolicies
• Practice: Deploy a multi-tier app on K8s

Daily routine (3 hours):

45 min: Tool documentation and tutorials
90 min: Build real projects
45 min: Coding practice (LeetCode Easy-Medium)

Phase 3: Production Skills (Days 61-80)

Goal: Develop SRE-specific expertise

Week 9-10: Monitoring and Observability

• Metrics (Prometheus, Grafana)
• Logging (ELK, Loki)
• Tracing (Jaeger, OpenTelemetry)
• SLOs, SLIs, Error Budgets
• Practice: Instrument an application end-to-end

Week 11-12: Incident Response

• On-call best practices
• Incident management frameworks
• Postmortem writing
• Chaos engineering basics
• Practice: Simulate and respond to incidents

Phase 4: Interview Sprint (Days 81-90)

Goal: Peak performance for interviews

Week 13: Mock Interviews

• 2 coding mock interviews
• 2 system design mock interviews
• 2 behavioral mock interviews
• Review and iterate on feedback

Week 14: Final Preparation

• Company-specific research
• Review all notes and weak areas
• Rest and mental preparation
• Logistics (test setup, quiet space)

Study Resources

Books (pick 1-2):

• "Site Reliability Engineering" (Google SRE Book) - Free online
• "The DevOps Handbook"
• "Designing Data-Intensive Applications"

Courses:

• Linux Foundation: CKA/CKAD prep
• Cloud provider certifications (AWS SA, GCP)

Practice platforms:

• Kubernetes: killer.sh, KodeKloud
• Linux: OverTheWire, LinuxJourney
• Coding: LeetCode (Easy-Medium), HackerRank

Weekly Progress Tracker

Week	Focus	Hours	Checkpoint
1-2	Linux	20-25	Can explain process lifecycle
3-4	Networking	20-25	Can troubleshoot DNS issues
5-6	CI/CD, IaC	25-30	Built working pipeline
7-8	Kubernetes	25-30	Deployed multi-tier app
9-10	Monitoring	25-30	Full observability stack
11-12	Incident Mgmt	20-25	Wrote practice postmortems
13-14	Mock Interviews	15-20	Completed 6 mocks

Total time investment: ~200 hours over 90 days

Adjustments by Current Level

If you're a beginner (0-2 YoE):

• Extend Phase 1 to 6 weeks
• Focus more on fundamentals
• Target Tier 3-4 companies first

If you're intermediate (3-5 YoE):

• Follow the plan as-is
• Add more system design practice
• Target Tier 2-3 companies

If you're senior (5+ YoE):

• Compress Phase 1 to 2 weeks
• Heavy focus on design and behavioral
• Target Tier 1-2 companies

Ready to begin? The next module covers Linux and Networking fundamentals—the foundation of every DevOps/SRE interview. :::