Cloud 6.01

Move SCD to Build Phase

Understanding the default SCD process, config:dump, smart wizards, time measurements, and how to optimize for minimal downtime.

Exam Critical: Understanding how to move SCD to build phase is ESSENTIAL! This is a key optimization that dramatically reduces production downtime.

SCD Build Phase Optimization

mindmap root((SCD Build Phase)) Default Process Deploy phase default Needs database Causes downtime Build Phase Benefits Reduce downtime More secure Pre generated config dump Process SSH to production Run config dump Copy config php Commit and deploy Smart Wizards ideal state master slave scd on demand scd on build scd on deploy Time Savings Build 1 52 vs Deploy 6 46 Total 3 22 vs 8 37 63 percent faster

Default SCD Process and Downtime Impact

Build vs Deploy Phase Capabilities

Both build and deploy phases can generate static content, but there's a critical difference:

Phase Database Available? Site Status Default?
Build NO - Requires config:dump Site UP No (requires setup)
Deploy YES - Always available Site DOWN (maintenance) Yes (default)

Critical Understanding

To generate static content, Magento needs to know what themes and locales are in use. This requires:

  • Database connection (readily available in deploy phase)
  • OR app/etc/config.php with scope data (from ./vendor/bin/ece-tools config:dump)

Why Deploy Phase is Default (But Not Best)

The Easiest ≠ The Best

Deploy Phase (Default)
  • ✓ Easy - database readily available
  • ✓ No setup required
  • ✗ Site is DOWN during SCD
  • ✗ Significant downtime
  • ✗ SCD time = downtime
Build Phase (Optimal)
  • ✓ Site stays UP during SCD
  • ✓ Minimal downtime
  • ✓ More secure (read-only)
  • ✗ Requires config:dump setup
  • ✗ Small config overhead

Process to Move SCD to Build Phase

5-Step Process

Prerequisites

  • Access to production environment via SSH
  • Git repository access
  • Understanding of deployment workflow

Step 1: SSH into Production

magento-cloud ssh -e production

Step 2: Run config:dump

./vendor/bin/ece-tools config:dump
What config:dump Does
  1. Runs bin/magento app:config:dump
  2. Filters configuration to ensure ONLY stores and websites are saved
  3. Updates app/etc/config.php with scope data

Step 3: Copy app/etc/config.php

Download the generated file to your local project:

# From production server
cat app/etc/config.php

# Or use magento-cloud CLI to download
magento-cloud ssh -e production "cat app/etc/config.php" > app/etc/config.php

Step 4: Commit to Git

git add app/etc/config.php
git commit -m "Add scope configuration for build-phase SCD"
git push origin master

Step 5: Deploy

The next deployment will automatically build static content in the build phase!

Result

Static content is now generated during build phase (site UP), not deploy phase (site DOWN). Downtime dramatically reduced!

Smart Wizards

ece-tools Optimization Wizards

Smart wizards help optimize deployment and operation of Cloud-hosted websites.

1. wizard:ideal-state

Command: ./vendor/bin/ece-tools wizard:ideal-state

Checks:

  • Static-content deploy happens in build stage
  • post_deploy hook is configured
  • SKIP_HTML_MINIFICATION is true

Note: This check runs as validator in build:generate command. Failure outputs warning but doesn't stop build.

2. wizard:master-slave

Command: ./vendor/bin/ece-tools wizard:master-slave

Checks:

  • MySQL slave connections configured
  • Redis slave connections configured

3. wizard:scd-on-demand

Command: ./vendor/bin/ece-tools wizard:scd-on-demand

Output: "SCD on demand is (enabled or disabled)."

Purpose: Quickly check if SCD_ON_DEMAND is enabled

4. wizard:scd-on-build

Command: ./vendor/bin/ece-tools wizard:scd-on-build

Uses: Global stage ScdOnBuild validator

Checks:

  • SCD_ON_DEMAND is disabled
  • SKIP_SCD is disabled
  • app/etc/config.php exists
  • app/etc/config.php contains scope configurations

5. wizard:scd-on-deploy

Command: ./vendor/bin/ece-tools wizard:scd-on-deploy

Uses: Global stage ScdOnDeploy validator

Checks:

  • SCD_ON_DEMAND is disabled
  • SKIP_SCD is disabled
  • Build-phase SCD is disabled

Reasons to Move SCD to Build Phase

Two Primary Benefits

1. Reduce Downtime

Impact: Dramatic reduction in deployment downtime

  • SCD happens while site is still UP
  • Deploy phase only runs migrations and config updates
  • Can reduce downtime by 60-80%!
  • Better user experience during deployments

2. Increased Security

Security Benefit: Pre-generated static content is more secure

  • Static content files are read-only
  • Cannot change files after generation
  • Reduces attack vector for MageCart-esque problems
  • Prevents malicious code injection into static files

MageCart Protection

Pre-generated, read-only static content prevents attackers from injecting malicious JavaScript to steal credit card data during checkout (common MageCart attack vector).

Time Measurements

Real-World Performance Data

Data from vanilla Magento install on integration branch with sample data:

Configuration Build Deploy Post-Deploy Total SCD Time
SCD on Deploy, Skip Minify 01:11 06:46 00:02 08:37 05:18
SCD on Deploy, Minify 01:10 07:31 00:02 09:20 06:04
SCD on Build, Skip Minify 01:52 00:48 00:02 03:22 00:41
SCD on Build, Minify 01:58 01:46 00:02 04:27 00:41
SCD on Demand 01:14 00:39 00:02 02:31 00:00

Key Insights

  • SCD on Deploy: 06:46 downtime (site in maintenance)
  • SCD on Build: 00:48 downtime (83% reduction!)
  • Total time: 08:37 vs 03:22 (61% faster)
  • Note: Disparity is MUCH GREATER with multiple themes/locales

Production Reality

For basic Magento Cloud deploy, building static content on deploy takes almost a minute extra downtime. With multiple themes and locales, this can be 5-10+ minutes!

SKIP_HTML_MINIFICATION Configuration

Additional Deployment Optimization

What It Does

Setting SKIP_HTML_MINIFICATION to true (default) prevents an additional file copy in deploy phase.

When HTML is Minified (SKIP_HTML_MINIFICATION = false):
  • Files copied from init/var/view_preprocessed to var/view_preprocessed
  • Takes additional (minimal) time during deploy
  • Reduces downloaded bytes for users

Trade-off Decision

HTML is NOT minified by default. Merchants must decide if fewer downloaded bytes justify slightly longer deploy time.

Recommendation: Keep SKIP_HTML_MINIFICATION = true for faster deploys. Use Varnish/CDN compression instead.

Practical Experience Exercise

Step-by-Step Testing

Part 1: Baseline (Deploy Phase SCD)

  1. Ensure NO scope data (stores/websites/groups) in app/etc/config.php
  2. Deploy code to Cloud
  3. Check time between maintenance mode enabled and disabled
  4. Record the downtime

Part 2: Optimized (Build Phase SCD)

  1. Use ece-tools config:dump to generate app/etc/config.php
  2. Copy file to local repository
  3. Push to Cloud
  4. Static content now built in build phase
  5. Record the new (much shorter) downtime

Part 3: Verify Configuration

For non-vanilla projects, ensure:

  • SCD_ON_DEMAND === false
  • SKIP_HTML_MINIFICATION === true
  • SKIP_SCD === false (in .magento.env.yaml build stage)
  • SCD_STRATEGY === compact

Exam Tips

Key Points to Remember

  • Default: SCD in deploy phase (easy but causes downtime)
  • Optimal: SCD in build phase (requires config:dump, minimal downtime)
  • config:dump: Generates app/etc/config.php with scope data
  • 5 steps: SSH, config:dump, copy, commit, deploy
  • Smart wizards: ideal-state, master-slave, scd-on-demand, scd-on-build, scd-on-deploy
  • wizard:ideal-state: Checks build SCD, post-deploy hook, SKIP_HTML_MINIFICATION
  • Benefits: Reduce downtime (60-80%), increase security (read-only)
  • Downtime comparison: 06:46 (deploy) vs 00:48 (build) - 83% reduction
  • SKIP_HTML_MINIFICATION: Default true, prevents file copy in deploy
  • config:dump filters: Only stores and websites saved, not all config
  • Security benefit: Read-only files prevent MageCart attacks
  • setup:upgrade: Must still run in deploy phase (unavoidable)
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