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ElasticsearchProjects

Portfolio-ready projects to demonstrate your skills

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Written by senior engineers. Reviewed for technical accuracy.· Updated 2025 · SynfraCore Elasticsearch Team
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Elasticsearch — Portfolio Projects

Build these projects to demonstrate real skills to employers. Each project is designed to be interview-worthy — something you can walk through in detail.

Project 1: Product Search with Explicit Mappings and Relevance Tuning

Level: Beginner-Intermediate | Time: 2 days

Build a realistic product search feature that demonstrates deliberate mapping decisions and measured relevance tuning, not just "it returns results."

Steps

1.Design an explicit mapping (not dynamic) for a realistic product catalog, using the multi-field pattern (text + .keyword) wherever a field needs both full-text search and exact-match/aggregation support
2.Load a realistic volume of sample data (thousands of products, not a handful) and build a bool query combining must (relevance-affecting) and filter (cached, non-scoring) clauses correctly
3.Add field boosts (multi_match with name^3, etc.) to tune relevance, but measure the effect with a small fixed set of test queries before/after each change — don't tune purely by eyeballing one result
4.Use _explain on at least one query to understand exactly why a specific document scored the way it did
5.Write a README documenting each mapping decision (why this field is text, why that one is keyword, why some are both) and each relevance-tuning change with its measured before/after effect

Skills Demonstrated

Deliberate, explicit mapping design (not relying on dynamic mapping in a demo meant to show real understanding)
Evidence-based relevance tuning using _explain, not guesswork
The must/filter distinction applied correctly in a real bool query

GitHub Repo Name

elasticsearch-product-search

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Project 2: Log Analytics Pipeline with ILM

Level: Intermediate | Time: 2-3 days

Build a realistic log ingestion and analytics setup that manages its own data lifecycle, not just an index that grows forever.

Steps

1.Design a time-based index pattern (e.g. logs-2026.07.19) and set up an ILM policy with real hot → warm → cold → delete phases and sensible age/size thresholds
2.Ingest a realistic volume of structured log data (via the Bulk API, not one-by-one indexing) and confirm rollover actually triggers as configured
3.Build aggregation-based dashboards-style queries: error rate by service over time (date_histogram + terms), p50/p95/p99 latency (percentiles), all using "size": 0 to avoid fetching raw documents unnecessarily
4.Deliberately let one index accumulate update/delete churn and observe segment fragmentation via GET /index/_stats (docs.deleted), then run a _forcemerge and document the before/after
5.Write a README explaining the ILM policy's phase thresholds and why they were chosen for this specific data's actual access pattern (recent logs queried often, old logs rarely)

Skills Demonstrated

Real ILM policy design tied to an actual data lifecycle, not just copying a default policy
Aggregation-based analytics query patterns used for dashboards
Diagnosing and fixing segment fragmentation with real evidence

GitHub Repo Name

elasticsearch-log-analytics-ilm

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Project 3: Cluster Health Diagnostics and a Deliberate Failure Drill

Level: Advanced | Time: 3-4 days

Stand up a real multi-node cluster and practice genuine failure diagnosis, not just reading about cluster health colors.

Steps

1.Run a 3-node cluster (Docker Compose is fine) with dedicated master-eligible nodes, and confirm quorum behavior — document what actually happens if you take down one node versus two
2.Deliberately create a yellow-status situation (e.g. an index with more replicas configured than available nodes) and use GET _cluster/allocation/explain to identify the specific, actual reason — not just observe the color
3.Simulate a mapping-explosion scenario in a throwaway index (index many documents with unpredictable, varying top-level field names) and observe the mapping field count grow — then fix it going forward with dynamic: false or the flattened type, and document the difference
4.Take a data node down entirely and confirm what happens to shards that had no replica versus shards that did — this should make the real, concrete difference between "replicas exist" and "replicas don't exist" visible, not theoretical
5.Write up the whole exercise as an incident-style report: what you did, what you observed at each step, and what would have actually happened in production if replicas hadn't existed

Skills Demonstrated

Real, hands-on cluster health diagnosis using _cluster/allocation/explain, not just color-watching
Understanding mapping explosion as a genuine, reproducible failure mode
Demonstrating the real consequence of missing replicas through actual failure injection

GitHub Repo Name

elasticsearch-cluster-diagnostics-lab

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Tips for Great Elasticsearch Projects

Show that you understand text vs. keyword as a deliberate choice, not default behavior. Every mapping decision in a strong project should be explainable — "this field is keyword because I need to aggregate on it, and text because I also need to search it" is a real answer; "I just used the default" is not.

Measure relevance changes, don't just eyeball one query. A project that shows "before/after with a fixed test query set" is far more convincing than "I added a boost and it looked better."

Elasticsearch is not a relational database. If a project's design implies FOREIGN KEY constraints, JOINs, or full ACID transactions across documents, that's a sign the project is being designed for the wrong tool — Elasticsearch is a search/analytics engine that typically sits alongside a primary database, not a replacement for one.

Portfolio Checklist

[ ] At least one project demonstrates explicit, deliberate mapping design (not relying on dynamic mapping)
[ ] At least one project includes measured relevance tuning with real before/after evidence
[ ] At least one project involves genuine multi-node cluster diagnostics, not a single-node demo
[ ] Each README explains the reasoning, not just the final configuration
[ ] You can walk through any of these projects for 5+ minutes without notes
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