SnowTower Administrator Guide

A comprehensive skill for administrators managing Snowflake infrastructure through SnowTower.

Who This Skill Is For

• Infrastructure administrators managing SnowDDL deployments
• Security admins handling user provisioning and roles
• DevOps engineers managing CI/CD pipelines
• On-call engineers troubleshooting production issues

---

Quick Command Reference

# Essential commands
uv run snowddl-plan          # Preview changes (ALWAYS run first)
uv run deploy-safe           # Apply changes safely
uv run manage-users          # User lifecycle management
uv run manage-warehouses     # Warehouse operations
uv run manage-costs          # Cost analysis

---

Core Operations

SnowDDL Deployment Workflow

CRITICAL: Always use deploy-safe, never raw snowddl-apply

# 1. Make changes to YAML files in snowddl/
vim snowddl/user.yaml

# 2. ALWAYS preview first
uv run snowddl-plan

# 3. Review the plan output carefully
# Look for: CREATE, ALTER, DROP, GRANT, REVOKE statements

# 4. Apply using safe deployment (preserves schema grants)
uv run deploy-safe

Why deploy-safe? SnowDDL excludes SCHEMA objects from management, which can cause it to revoke schema-level grants. The deploy-safe wrapper automatically restores these grants after every deployment, preventing dbt and other tools from losing permissions.

Understanding Plan Output

[APPLY] CREATE USER "NEW_USER"        ← New object will be created
[APPLY] ALTER USER "EXISTING_USER"    ← Object will be modified
[APPLY] DROP USER "OLD_USER"          ← Object will be deleted (CAREFUL!)
[APPLY] GRANT ROLE "X" TO USER "Y"    ← Permission will be added
[APPLY] REVOKE ROLE "X" FROM USER "Y" ← Permission will be removed

Red flags to watch for:

• Unexpected DROP statements
• Mass REVOKE statements (might be schema drift)
• Changes to admin roles (ACCOUNTADMIN, SECURITYADMIN)

---

User Management

Creating a New User

Option 1: Interactive wizard (recommended)

uv run manage-users create

Option 2: Edit YAML directly

# snowddl/user.yaml
NEW_USER:
  comment: "Data Analyst - Analytics Team"
  type: PERSON
  default_role: ANALYST_ROLE__B_ROLE
  default_warehouse: MAIN_WAREHOUSE
  email: user@company.com
  authentication:
    password: !decrypt |
      gAAAAABl...encrypted...
    rsa_public_key: |
      -----BEGIN PUBLIC KEY-----
      MIIBIjAN...
      -----END PUBLIC KEY-----

Option 3: Non-interactive

uv run manage-users create \
  --first-name Jane \
  --last-name Smith \
  --email jane@company.com \
  --role ANALYST_ROLE

User Types

Type	Use For	MFA Required	Network Policy
PERSON	Human users	Yes (by 2026)	Applied
SERVICE	Service accounts	No	Not applied

Encrypting Passwords

# Generate Fernet key (one-time setup)
uv run util-generate-key

# Encrypt a password
uv run snowddl-encrypt "MySecurePassword123!"
# Output: gAAAAABl...

# Use in YAML with !decrypt tag
authentication:
  password: !decrypt |
    gAAAAABl...encrypted_output...

RSA Key Setup for Users

# Generate keys for a user
uv run generate-rsa-batch --users NEW_USER

# Or manually:
openssl genrsa 2048 | openssl pkcs8 -topk8 -inform PEM -nocrypt -out user_key.p8
openssl rsa -in user_key.p8 -pubout -out user_key.pub

# Add public key to user.yaml
cat user_key.pub

---

Role Hierarchy

SnowDDL Role Naming Convention

ROLE_NAME__B_ROLE    → Business role (assigned to users)
ROLE_NAME__T_ROLE    → Technical role (assigned to business roles)
DB__SCHEMA__S_ROLE   → Schema role (auto-created by SnowDDL)

Role Assignment Flow

User → Business Role (__B_ROLE) → Technical Roles (__T_ROLE) → Permissions

Creating Roles

Business Role (snowddl/business_role.yaml):

ANALYST_ROLE:
  comment: "Business analysts with read access"
  tech_roles:
    - STRIPE_READER_ROLE
    - ANALYTICS_READER_ROLE
  warehouse_usage:
    - MAIN_WAREHOUSE
  schema_read:
    - PROJ_STRIPE.ANALYTICS

Technical Role (snowddl/tech_role.yaml):

STRIPE_READER_ROLE:
  grants:
    DATABASE:USAGE:
      - SOURCE_STRIPE
      - PROJ_STRIPE
    SCHEMA:USAGE:
      - SOURCE_STRIPE.STRIPE_WHY
      - PROJ_STRIPE.PROJ_STRIPE
    TABLE:SELECT:
      - SOURCE_STRIPE.STRIPE_WHY.*

---

Database & Schema Management

Creating a Database

# Create directory
mkdir snowddl/MY_NEW_DB

# Add params.yaml
cat > snowddl/MY_NEW_DB/params.yaml << 'EOF'
comment: "New database for analytics project"
is_transient: false
EOF

# Deploy
uv run snowddl-plan
uv run deploy-safe

Creating a Schema

# Create schema directory
mkdir snowddl/MY_DB/MY_SCHEMA

# Add params.yaml
cat > snowddl/MY_DB/MY_SCHEMA/params.yaml << 'EOF'
comment: "Schema for raw data ingestion"
is_transient: false
is_sandbox: false
EOF

Schema Types

Parameter	Effect
is_transient: true	No Time Travel, no Fail-safe
is_sandbox: true	Creates as TRANSIENT schema

---

CI/CD Operations

GitHub Actions Workflows

Workflow	Trigger	Purpose
ci.yml	PRs, pushes	Lint + test validation
release.yml	Tags v*	Create GitHub release
labeler.yml	PRs	Auto-label by file type
changelog.yml	Push to main	Update changelog

Making Infrastructure Changes via PR

# 1. Create feature branch
git checkout v0.2
git checkout -b feature/add-new-user

# 2. Make YAML changes
vim snowddl/user.yaml

# 3. Validate locally
uv run pre-commit run --all-files
uv run pytest

# 4. Commit and push
git add .
git commit -m "feat: Add new user JANE_DOE"
git push -u origin feature/add-new-user

# 5. Create PR
gh pr create --base v0.2

# 6. CI runs automatically, merge after approval

Release Process

# After all PRs merged to v0.2
git checkout main
git pull
git merge v0.2
git tag v0.2.0
git push origin main --tags
# Release workflow creates GitHub release automatically

---

Troubleshooting

Schema Grant Drift

Symptom: Plan shows hundreds of REVOKE statements for schema grants

Cause: SnowDDL doesn't manage SCHEMA objects directly; grants from dbt or other tools appear as drift

Solution:

# Always use deploy-safe which auto-applies schema grants
uv run deploy-safe

# Or manually apply schema grants
uv run apply-schema-grants

Authentication Failures

# Diagnose authentication issues
uv run util-diagnose-auth

# Fix common auth problems
uv run util-fix-auth

# Check specific user
snow sql -q "DESCRIBE USER USERNAME"

User Locked Out

-- Check user status
SHOW USERS LIKE 'USERNAME';

-- Unlock user (as ACCOUNTADMIN)
ALTER USER USERNAME SET MINS_TO_UNLOCK = 0;

-- Check login history
SELECT * FROM SNOWFLAKE.ACCOUNT_USAGE.LOGIN_HISTORY
WHERE USER_NAME = 'USERNAME'
ORDER BY EVENT_TIMESTAMP DESC
LIMIT 10;

SnowDDL Errors

"Object does not exist"

• Run with ACCOUNTADMIN: uv run snowddl-plan uses -r ACCOUNTADMIN
• Check object was created in correct database/schema

"Insufficient privileges"

• Verify SNOWFLAKE_ROLE is set to ACCOUNTADMIN
• Check the service account has required permissions

Exit code 8

• Means "changes applied successfully"
• Not an error, SnowDDL uses this to indicate modifications were made

---

Security Operations

Network Policies

# snowddl/network_policy.yaml
corporate_network_policy:
  allowed_ip_list:
    - 192.0.2.0/24
    - 10.0.0.0/8
  comment: "Corporate network access only"

MFA Compliance

Deadline: March 2026 for all human users

# Check MFA status
uv run manage-security --check-mfa

# List users without MFA
snow sql -q "
  SELECT name, has_mfa_registered
  FROM SNOWFLAKE.ACCOUNT_USAGE.USERS
  WHERE type = 'PERSON' AND NOT has_mfa_registered
"

Emergency Access

The STEPHEN_RECOVERY account is configured without network policy for emergency access:

• Use only when primary access methods fail
• Requires password authentication
• Document all usage

---

Cost Management

# Analyze costs
uv run manage-costs --analyze

# Check warehouse usage
uv run manage-warehouses --status

# Suspend all warehouses (emergency)
uv run manage-warehouses --suspend-all

Warehouse Configuration

# snowddl/warehouse.yaml
MAIN_WAREHOUSE:
  size: XSMALL
  auto_suspend: 60        # seconds
  auto_resume: true
  min_cluster_count: 1
  max_cluster_count: 1
  resource_monitor: main_monitor

---

Key File Locations

File	Purpose
snowddl/user.yaml	User accounts
snowddl/business_role.yaml	Business roles
snowddl/tech_role.yaml	Technical roles with grants
snowddl/warehouse.yaml	Warehouse configuration
snowddl/*_policy.yaml	Security policies
snowddl/{DB}/params.yaml	Database configuration
snowddl/{DB}/{SCHEMA}/params.yaml	Schema configuration

---

Environment Variables

Required in .env:

SNOWFLAKE_ACCOUNT=your_account
SNOWFLAKE_USER=SNOWDDL
SNOWFLAKE_ROLE=ACCOUNTADMIN
SNOWFLAKE_WAREHOUSE=ADMIN
SNOWFLAKE_PRIVATE_KEY_PATH=~/.ssh/snowflake_rsa_key.p8
SNOWFLAKE_CONFIG_FERNET_KEYS=your_fernet_key

---

Emergency Procedures

Rollback Last Deployment

# Revert YAML changes
git checkout HEAD~1 -- snowddl/

# Re-apply
uv run deploy-safe

Complete Service Account Reset

# Regenerate RSA keys
uv run generate-rsa-batch --users SNOWDDL --force

# Update in Snowflake
snow sql -q "ALTER USER SNOWDDL SET RSA_PUBLIC_KEY='...'"

# Update GitHub secrets
gh secret set SNOWFLAKE_PRIVATE_KEY < new_key.p8

Health Check

# Quick health check
uv run monitor-health

# Full system audit
uv run manage-security --full-audit