Drupal Configuration Management

Comprehensive guide for Drupal configuration management including imports, exports, config splits, and environment syncing.

Remote CLI — host-neutral

Examples below use Pantheon's Terminus (terminus drush <site>.<env> -- <cmd>). The commands are identical on any host — substitute your platform's remote-drush form. If your platform provides Drush site aliases, the generic drush @<alias> <cmd> works everywhere.

The auto-confirm warning below applies to every host — append --no to cim/config:import to preview instead of apply. Drush defaults to --yes when invoked non-interactively (which all remote-CLI wrappers do).

Problem: Avoid Accidental Config Imports

CRITICAL: Terminus drush commands default to --yes unless explicitly told --no. This means commands like config:import or cim will AUTO-CONFIRM and import configuration even when you only want to inspect differences.

Dangerous vs Safe Patterns

❌ DANGEROUS - Auto-imports without confirmation:

terminus drush {site}.{env} -- cim --diff  # DON'T DO THIS!

✅ SAFE - Shows diff without importing:

terminus drush {site}.{env} -- cim --no --diff

✅ SAFEST - Read-only commands:

terminus drush {site}.{env} -- config:get config.name
terminus drush {site}.{env} -- config:status

Table of Contents

1. Preferred Prod Config Merge Workflow
2. Configuration Import & Export Basics
3. Config Splits Overview
4. Complete vs Partial Splits
5. Config Split Commands
6. Safe Inspection Workflow
7. Syncing Config from Upstream Environments

Configuration Import & Export Basics

Default to one named object at a time. A blanket cex writes every active-vs-sync difference to disk and a blanket cim imports (and deletes) every difference, so in a tree with drift you did not create they sweep that drift into your commit or your database. An agent changes config with config:get / config:set / config:delete / a partial import of one file, and leaves the full import to the deploy (the tail is in the drupal-deploy-safety skill). Run a blanket export only from a clean, committed tree when a full export is the point (a prod config merge, a split change), and review git status config/ afterwards. Full rules: surgical-config.md.

Exporting Configuration

Export ALL configuration (from active config to YAML files; clean tree only, see above):

# Local
ddev drush config:export
ddev drush cex

# Remote
terminus drush {site}.{env} -- config:export

Export a SINGLE config object:

# Get config and save to file
ddev drush config:get config.name --format=yaml > config/default/config.name.yml

# Example: Export a specific view
ddev drush config:get views.view.content --format=yaml > config/default/views.view.content.yml

Importing Configuration

Import ALL configuration (from YAML files to active config; this is what a deploy does, so preview locally and leave remote imports to the deploy tail):

# Local
ddev drush config:import
ddev drush cim

# Remote (DANGEROUS - auto-confirms with terminus!)
terminus drush {site}.{env} -- config:import --no  # Use --no to preview only

Import a SINGLE config object (partial import from a directory holding only that file; under DDEV the directory must be inside the project, see surgical-config.md):

mkdir -p .config-one && cp config/default/config.name.yml .config-one/
ddev drush config:import --partial --source=/var/www/html/.config-one -y
rm -rf .config-one

# Or use config:set for specific values
ddev drush config:set config.name key.subkey value

Best Practice: Always preview changes first:

ddev drush config:import --no --diff  # Show what would change
ddev drush cim --no --diff            # Alias

Config Split Commands

CRITICAL: Active vs Exported Configuration

⚠️ IMPORTANT: When updating config split definitions, changes must be in ACTIVE configuration (database), not just exported files!

Workflow:

1. Edit config/default/config_split.config_split.{name}.yml
2. Import to make active: a single-file partial import (see above) OR use PHP (see below)
3. Export: ddev drush cex. This is the one routine case that needs a full export, because config_split writes the split directory and its patch files during cex. Start from a clean tree and revert anything in git status config/ you did not intend.

Quick method - Set active config via PHP:

ddev drush php:eval "\$config = \Drupal::configFactory()->getEditable('config_split.config_split.local'); \$config->set('partial_list', ['config.name']); \$config->save();"

See examples.md for detailed workflow.

Export Config with Splits

Export ALL config including active splits:

ddev drush config:export

This exports:

• Base config to config/default/
• Active split config to config/{split-name}/

Export a specific split:

ddev drush config-split:export {split-name}
ddev drush csex {split-name}

Import Config with Splits

Import ALL config including active splits:

ddev drush config:import
ddev drush cim

This imports:

• Base config from config/default/
• Active split config from config/{split-name}/

Import a specific split:

ddev drush config-split:import {split-name}
ddev drush csim {split-name}

Import only base config (ignore splits): Drush 13's config:import has no option for this (--skip-modules was Drush 8). drush config-split:deactivate <split> itself imports the config without the split, writing status: false into active config; a later full config:import re-activates the split if its synced YAML has status: true. To keep it off across imports, set a status override: drush config-split:status-override <split> inactive (stored in state; values active|inactive|default, alias csso), or in settings.php:

ddev drush config-split:deactivate {split-name}                     # one-off
ddev drush config-split:status-override {split-name} inactive       # sticks across imports

$config['config_split.config_split.{split-name}']['status'] = FALSE;  // settings.php

A --partial import skips config transformation, so no split is applied to it at all.

Activate/Deactivate Splits

Activate a split:

ddev drush config-split:activate {split-name}

Deactivate a split:

ddev drush config-split:deactivate {split-name}

Check Split Status

List all splits and their status:

ddev drush config-split:status
ddev drush css

Example output:

Split       Active  Configuration directory
local       Yes     ../config/local
dev         No      ../config/dev
test        No      ../config/test

Safe Inspection Workflow

Use config:get and config:status for read-only inspection, or use --no flag with cim/cex to prevent auto-confirmation.

Get Config Values

# Get full config object
terminus drush {site}.{env} -- config:get config.name

# Get as YAML
terminus drush {site}.{env} -- config:get config.name --format=yaml

# Extract specific values
terminus drush {site}.{env} -- config:get config.name 2>&1 | grep "setting_name"

Compare Local vs Remote

# View diffs without importing (SAFE with --no)
terminus drush {site}.{env} -- cim --no --diff

# Get remote and compare manually
terminus drush {site}.{env} -- config:get config.name --format=yaml > /tmp/remote.yml
diff -u config/default/config.name.yml /tmp/remote.yml

CRITICAL: Always use --no flag with terminus! Without it, commands auto-confirm.

Apply Changes

Preferred: never hand-author the YAML. Either make the change in the site (UI, config:set for simple config, or the entity API for config entities) and export that one object, or, to take an environment's value, write that environment's config:get output for the one object (see surgical-config.md):

ddev drush config:get config.name --format=yaml > config/default/config.name.yml
# or: terminus drush {site}.{env} -- config:get config.name --format=yaml > config/default/config.name.yml
git diff config/default/config.name.yml
git add config/default/config.name.yml
git commit -m "Update config from {env}"

Syncing Config from Upstream Environments

Quick Methods

Single config object:

terminus drush {site}.{env} -- config:get config.name --format=yaml > config/default/config.name.yml
git add config/default/config.name.yml && git commit -m "Update from {env}"
# Then apply that one file locally with a single-file partial import (see above)

Full config sync via rsync:

Caution: a remote cex writes every drifted config object on that environment, and a local cim imports (and deletes) everything that differs. Never run a blanket export/import against a shared or remote environment as a casual step — prefer the single-config method above, and review the full diff before anything is imported. See surgical-config.md.

terminus drush {site}.{env} -- cex
terminus rsync {site}.{env}:code/config/default /tmp/remote
diff -r config/default /tmp/remote  # Review
cp /tmp/remote/*.yml config/default/
git add config/default/ && git commit -m "Sync from {env}"
ddev drush cim

Via database pull (DDEV + Pantheon). This is a deliberate full export: commit your own work first and restore any of your files the export deletes, as in prod-config-merge.md:

ddev pull pantheon --environment={env}  # Warning: Overwrites local DB!
ddev drush cex
git diff config/ && git add config/ && git commit -m "Config from {env}"

See examples.md for detailed workflows.

Best practices: Review diffs, commit separately, test locally, document source, avoid syncing environment-specific config.

Deep Dive References

For comprehensive technical documentation, see:

• config-split-deep-dive.md - Complete technical reference on Config Split 2.0, patch files, export/import process, and dependency handling
• surgical-config.md - One-config-at-a-time export/set/delete for agents, the core.extension.yml exception, raw config writes that drop dependencies, baked (PHP-computed) config, and verifying imports with config:status
• examples.md - Practical examples and workflows

References

Config Status Check

Check what config would be imported (read-only):

# Local environment
ddev drush config:status

# Remote environment
terminus drush {site}.{env} -- config:status

Best Practices

1. Always inspect before importing - Use config:get and --no --diff flags
2. Change config in the site, export one object - UI / config:set / entity API, then config:get --format=yaml; hand-editing exported YAML is the exception (it skips dependency calculation), and when you do it, import that one file and confirm with config:status
3. One config type per commit - Separate concerns for clean history
4. Clear commit messages - Reference source environment
5. Clean up temp files - Remove temporary YAML files
6. Verify before committing - Always review git diff output
7. Test locally first - Import and test before deploying
8. Use config splits - Keep environment-specific config separate

Troubleshooting

Config files deleted from working directory

If files are marked as deleted in git status:

git checkout HEAD -- config/default/*.yml

This can happen if a drush command runs unexpectedly.

Split not activating

Check split status:

ddev drush config-split:status

Manually activate:

ddev drush config-split:activate {split-name}
# Save the activation state: export only the split definition
ddev drush config:get config_split.config_split.{split-name} --format=yaml > config/default/config_split.config_split.{split-name}.yml

Config deleted from config/default on export

COMMON ISSUE: Config (like search_api.server.my_search_server) gets removed from config/default/ when you run drush cex.

Root cause (99% of cases): Config is in complete_list instead of partial_list!

Complete split = Config is REMOVED from config/default/ and moved to split directory entirely Partial split = Config STAYS in config/default/, only differences are patched

Diagnosis:

# Check if config is in complete_list (will be deleted from config/default)
grep -A10 "complete_list:" config/default/config_split.config_split.local.yml

# Check if config is in partial_list (will stay in config/default)
grep -A10 "partial_list:" config/default/config_split.config_split.local.yml

Solution: Move from complete_list to partial_list

# Edit the split definition
# Move: search_api.server.my_search_server
# FROM: complete_list
# TO: partial_list

ddev drush cex  # Re-export
# Check that config/default/search_api.server.my_search_server.yml exists
# Check that config/local/config_split.patch.search_api.server.my_search_server.yml exists

See config-split-deep-dive.md for complete technical explanation.

Config won't import

Common issues:

• Dependencies missing: Install required modules first
• Site UUID mismatch ("Site UUID in source storage does not match the target storage"): the database was installed separately from the exported config. Install from config with drush site:install --existing-config, or set system.site:uuid to the exported value with drush config:set system.site uuid <uuid>
• Config entity UUID differs: not an error, but the import deletes and recreates that entity (for a field storage, its data goes with it); see the drupal-config-reconcile skill

Drush 13's config:import has no --skip-config option. To keep one object out of an import, use the config_ignore module or a single-file partial import (above).

Related Commands

Read-only: config:get, config:status Exports: config:export (alias: cex) Imports: config:import (alias: cim) - Use with --no --diff to preview Splits: config-split:status, csex, csim, config-split:activate