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gamaware merged 3 commits into from
Apr 14, 2026
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feat: add database scalability labs with interactive visualizer #42

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68b1b3e
feat: add database scalability labs with interactive visualizer
gamaware Apr 14, 2026
2d72a4e
fix: address CI lint failures in database visualizer
gamaware Apr 14, 2026
5e41b4f
fix: address Copilot review feedback on database labs
gamaware Apr 14, 2026
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3 changes: 2 additions & 1 deletion .pre-commit-config.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,8 @@ repos:
01-introduction-horizontal-scalability/ecsdemo-.*/kubernetes/.*|
01-introduction-horizontal-scalability/ecsdemo-.*/copilot/.*|
08-cloud-networking-vpc/cloudformation/.*|
09-distributed-file-systems/cloudformation\.yaml
09-distributed-file-systems/cloudformation\.yaml|
10-databases/.*/cloudformation\.yaml
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Comment on lines +13 to +14
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@coderabbitai coderabbitai Bot Apr 14, 2026

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⚠️ Potential issue | 🟠 Major

Do not exclude Module 10 CloudFormation templates from YAML validation.

Line 13–Line 14 broadens check-yaml exclusions to skip all 10-databases/*/cloudformation.yaml, which removes syntax validation for newly added infra templates. Keep these files validated and only carve out exclusions for parser-incompatible edge cases with clear justification.

Suggested fix 
       - id: check-yaml
         exclude: |
           (?x)^(
             01-introduction-horizontal-scalability/ecsdemo-.*/kubernetes/.*|
             01-introduction-horizontal-scalability/ecsdemo-.*/copilot/.*|
             08-cloud-networking-vpc/cloudformation/.*|
-            09-distributed-file-systems/cloudformation\.yaml|
-            10-databases/.*/cloudformation\.yaml
+            09-distributed-file-systems/cloudformation\.yaml
           )$

Based on learnings: Applies to .yml,.yaml : All YAML files must pass check-yaml validation.

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In @.pre-commit-config.yaml around lines 13 - 14, The check-yaml exclusion
currently skips all Module 10 CloudFormation templates via the pattern
"10-databases/.*/cloudformation\.yaml"; remove that pattern (or replace it with
a narrowly scoped exception for the specific parser-incompatible file) from the
exclusions in .pre-commit-config.yaml so that all Module 10 (*.yml/*.yaml)
CloudFormation templates are validated by check-yaml; if you must keep an
exclusion, document the exact filename and reason and use that exact path
instead of the broad "10-databases/.*/cloudformation\.yaml" pattern.

)$
- id: check-json
- id: check-added-large-files
Expand Down
42 changes: 39 additions & 3 deletions .secrets.baseline
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Original file line number Diff line number Diff line change
Expand Up @@ -190,14 +190,14 @@
"filename": "06-security-https-oauth2-keycloak/README.md",
"hashed_secret": "44b5ba9d33e8bcaefe1d26c4665f20a90fb84b5a",
"is_verified": false,
"line_number": 665
"line_number": 668
},
{
"type": "Secret Keyword",
"filename": "06-security-https-oauth2-keycloak/README.md",
"hashed_secret": "2be88ca4242c76e8253ac62474851065032d6833",
"is_verified": false,
"line_number": 699
"line_number": 702
}
],
"08-cloud-networking-vpc/LAB-MACOS.md": [
Expand All @@ -217,7 +217,43 @@
"is_verified": false,
"line_number": 108
}
],
"10-databases/mysql/docker-compose.yml": [
{
"type": "Secret Keyword",
"filename": "10-databases/mysql/docker-compose.yml",
"hashed_secret": "e63a0ab2f8e7ecde486b42ebfec16d4434840af4",
"is_verified": false,
"line_number": 6
}
],
"10-databases/mysql/setup.sh": [
{
"type": "Secret Keyword",
"filename": "10-databases/mysql/setup.sh",
"hashed_secret": "7667ad761bd61125e6eb84aafc63fe3bb914ab5b",
"is_verified": false,
"line_number": 81
}
],
"10-databases/visualizer/docker-compose.yml": [
{
"type": "Secret Keyword",
"filename": "10-databases/visualizer/docker-compose.yml",
"hashed_secret": "e63a0ab2f8e7ecde486b42ebfec16d4434840af4",
"is_verified": false,
"line_number": 8
}
],
"10-databases/visualizer/setup.sh": [
{
"type": "Secret Keyword",
"filename": "10-databases/visualizer/setup.sh",
"hashed_secret": "7667ad761bd61125e6eb84aafc63fe3bb914ab5b",
"is_verified": false,
"line_number": 54
}
]
},
"generated_at": "2026-03-28T05:23:05Z"
"generated_at": "2026-04-14T01:35:11Z"
}
63 changes: 63 additions & 0 deletions 10-databases/LAB.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
# Lab 10: Database Scalability

## Main Lab (Interactive Visualizer)

The primary lab for this module is an interactive web visualizer
connected to a live MySQL primary-replica cluster. It covers three
scalability mechanisms through animated diagrams, real SQL execution,
and a built-in SQL console.

| Lab | What It Covers | Time |
| --- | --- | --- |
| [Interactive Visualizer](visualizer/LAB-VISUALIZER.md) | Replication, ACID transactions, indexing -- all via browser | ~45 min |

```bash
cd 10-databases/visualizer
./setup.sh
# Open http://localhost:8081
```

## Optional Labs (CLI-based, deeper dive)

For students who want to go deeper with other database paradigms,
three optional CLI labs use the same university enrollment data model:

| Lab | Database | Scalability Mechanisms | Time |
| --- | --- | --- | --- |
| [10A: MySQL](mysql/LAB-MYSQL.md) | MySQL 8 (Relational) | GTID replication, ACID transactions, indexing | ~30 min |
| [10B: MongoDB](mongodb/LAB-MONGODB.md) | MongoDB 7 (Document) | Replica set, read/write concerns, denormalization | ~30 min |
| [10C: Cassandra](cassandra/LAB-CASSANDRA.md) | Cassandra 4.1 (Wide-column) | Multi-node ring, tunable consistency, partition keys | ~30 min |

## Scalability Mechanisms Compared

| Mechanism | MySQL | MongoDB | Cassandra |
| --- | --- | --- | --- |
| **Replication** | Primary + replica (GTID) | 3-node replica set | 3-node ring (RF=3) |
| **Failover** | Manual promotion | Automatic election | No single point of failure |
| **Consistency** | ACID transactions | Tunable write/read concern | Tunable CL (ONE/QUORUM/ALL) |
| **Schema** | Rigid, normalized | Flexible, denormalized | Query-driven, partition keys |
| **Scaling reads** | Add read replicas | Read from secondaries | Read from any node |
| **Scaling writes** | Vertical only | Sharding (manual) | Add nodes to ring |

## Shared Data Model

All labs use the same university enrollment scenario:

- **Students** -- 10 students with name, email, major
- **Courses** -- 4 courses with code, title, capacity
- **Enrollments** -- student-to-course relationships

This lets you compare how the same data is modeled differently in
each paradigm (tables with foreign keys vs embedded documents vs
partition-key-driven tables).

## Environment Options

Each lab supports two environments:

| Environment | What You Need | Setup |
| --- | --- | --- |
| **Local** | Docker Desktop | `./setup.sh` in the lab directory |
| **EC2** | Browser + SSH | Upload `cloudformation.yaml` via AWS Console |

Run one lab at a time to avoid port conflicts and resource contention.
Comment on lines +54 to +63
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@coderabbitai coderabbitai Bot Apr 14, 2026

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⚠️ Potential issue | 🟠 Major

Add EC2 sizing guidance for the multi-node labs.

This table implies every lab is fine on a generic EC2 host, but the MongoDB and Cassandra labs run multiple database nodes and are much heavier than a standard free-tier-style instance. Call out minimum sizing here, or steer low-resource users to local setup / MySQL first.

📝 Suggested fix 
 | **Local** | Docker Desktop | `./setup.sh` in the lab directory |
 | **EC2** | Browser + SSH | Upload `cloudformation.yaml` via AWS Console |
 
+> Note: the MongoDB and Cassandra labs run multiple database nodes and typically need more memory than a standard AWS Free Tier-style instance.
+> If you're on a low-resource host, prefer local Docker or start with the MySQL lab first.
+
 Run one lab at a time to avoid port conflicts and resource contention.

As per coding guidelines, "Review lab content for technical accuracy, clear step-by-step instructions, and educational value. Flag any steps that may not work in a standard AWS Free Tier environment."

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@10-databases/LAB.md` around lines 54 - 63, The "Environment Options" section
and its table (headers "Environment Options", rows "Local" and "EC2", and
artifacts like `./setup.sh` and `cloudformation.yaml`) needs EC2 sizing
guidance: update this section to call out that multi-node labs (MongoDB,
Cassandra) require larger instances (recommend minimum t3.medium/t3.large or
m5.large with 2+ vCPUs and >=4–8GB RAM and adequate EBS) or advise users on
alternatives (use Local/Docker or run single-node MySQL first) and add a short
note directing low-resource users to the Local setup or to follow smaller
single-node lab options; keep the guidance brief and place it directly below the
existing table.

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