Variables

Variables are how an environment differs from its siblings without the code differing. They are written into the application's .env file on every deploy.

#Two places to set them

On the project, where they apply to every environment. On an environment, where they apply there and nowhere else.

An environment defining a name the project already defines replaces it, there only. That is the entire rule — there is no third scope and no precedence table.

The console says which is which. A variable listed as inherited from project is not editable on the environment page: editing it there would silently create an override, and the next person to change the project value would wonder why one environment ignored them.

#Secrets

Mark a variable secret and its value is encrypted at rest and never shown again — not in the list, not in the edit form, not in a backup you can read. You can replace it; you cannot read it back.

Mark anything secret that would matter if it leaked: API keys, tokens, the mail relay password. There is no cost to marking too much.

Anybody from Developer up can add and change ordinary variables. A secret is replaced or removed by an Admin or Owner, and it cannot be turned back into a plain variable: a value that has been secret should be rotated, not revealed.

#Names the platform owns

Some names are set for you and cannot be redefined. Redefining them would either break the environment or point it at another tenant's service, so the form refuses them when you type them.

They are also the contract your code reads. Every value below is written into the environment's .env — the container's environment — and is what your settings.php, config/database.php or wp-config.php should read instead of anything committed to the repository. A value marked absent when is only there when the condition holds, so read it with a fallback rather than assuming it.

#Where the site is

Name	What it is
VALLIC_ENVIRONMENT	The environment's name — production, staging, pr-42.
VALLIC_ENVIRONMENT_TYPE	What kind it is: production, staging, development or preview. The value to switch behaviour on — error verbosity, an environment indicator, whether to send real mail.
PROJECT_MODE	The same as VALLIC_ENVIRONMENT_TYPE, under the name older images read.
VALLIC_SLUG	The environment's slug, {project}-{environment}, unique across the platform.
PROJECT_NAME	The same as VALLIC_SLUG, under the name the images read.
VALLIC_HOSTNAMES	Every hostname the edge routes to this environment, comma-separated. Trust these Host headers and no others. Absent until something routes here.
PROJECT_BASE_URL	https:// and the primary hostname — the one every other hostname redirects to. What to write into absolute links when no request says. Absent until something routes here.
DRUSH_OPTIONS_URI	Drupal projects only: PROJECT_BASE_URL under the name Drush reads, so cron and one-off commands write the same URLs a request would.

#Secrets

Name	What it is
VALLIC_ENTROPY	256 random bits, base64-encoded, generated once per environment and never changed. Derive the site's own secrets from it — Drupal's hash salt, WordPress's salts — rather than committing them. Arrives through the secret channel, so it is never in a task payload.

#Database

Name	What it is
DB_HOST	The database service, reachable by this name from every container. Absent when the stack runs no database.
DB_PORT	Its port.
DB_DRIVER	mysql for MariaDB, pgsql for PostgreSQL.
DB_NAME	The database, created on the service's first start.
DB_USER	The application's user — not the superuser.
DB_PASSWORD	Its password. Generated once with the environment and never regenerated. Arrives through the secret channel.
DB_ROOT_PASSWORD	The superuser's password, on engines that have one. For a migration or a repair, not for the site.
DATABASE_URL	The same credentials as one connection string, which is what Doctrine reads and what most Node and Go drivers accept. Arrives through the secret channel, because it carries the password.
DB_CONNECTION	The same value as DB_DRIVER, under the name Laravel reads.
DB_DATABASE	The same value as DB_NAME, under the name Laravel reads.
DB_USERNAME	The same value as DB_USER, under the name Laravel reads.

#Services in the stack

Name	What it is
REDIS_HOST	The cache service, whether it is Redis or Valkey — both speak the same protocol and the name is what the Drupal redis module reads. Absent when the stack runs neither.
REDIS_PORT	Its port, 6379.
VALKEY_HOST	The Valkey service by its own name, when the stack runs Valkey.
SOLR_HOST	The Solr service, when the stack runs it. Port 8983.
SOLR_USER	The user Solr's login accepts, solr. Solr refuses a request without it.
SOLR_PASSWORD	Its password. Derived per environment and never regenerated. Arrives through the secret channel.
VARNISH_HOST	The HTTP cache in front of the application, when the stack runs it — where to send purge requests. A purge sent here needs no key.
VARNISH_PURGE_KEY	The key a purge needs when it comes in from outside, in an X-VC-Purge-Key header. Arrives through the secret channel.
SMTP_HOST	The mail relay, when the stack runs one. Port 25 from inside the stack; the relay is what talks to the outside world.
MEILISEARCH_HOST	The Meilisearch service, when the stack runs it. Port 7700.
RABBITMQ_HOST	The RabbitMQ broker, when the stack runs it.
RABBITMQ_PORT	Its AMQP port, 5672.
RABBITMQ_USER	The user to connect as, app. The image's guest is removed.
RABBITMQ_PASSWORD	Its password. Derived per environment and never regenerated. Arrives through the secret channel.
RABBITMQ_URL	The same as one amqp:// URL, on the default virtual host. Arrives through the secret channel, because it carries the password.
MEILI_MASTER_KEY	Meilisearch's master key, which the service starts with and the application authenticates with. Derived per environment and never regenerated. Arrives through the secret channel.

#CDN

Name	What it is
VALLIC_CDN_PURGE_URL	Where to POST a purge, on this machine's loopback. Present only when the project has bought a CDN.
VALLIC_CDN_PURGE_TOKEN	Says which environment is asking. It is not a CDN credential and cannot reach another environment's cache. Arrives through the secret channel.

#Files

Name	What it is
VALLIC_PUBLIC_DIR	Absolute path, inside the container, of the directory the framework serves uploads from. It outlives every release.
VALLIC_PRIVATE_DIR	Absolute path of the directory that is never served — Drupal's private files, Laravel's storage/app. It outlives every release.
S3_FILES_ENDPOINT	Object storage for the site's files, when a bucket is attached to the environment: the endpoint.
S3_FILES_REGION	Its region.
S3_FILES_BUCKET	The bucket.
S3_FILES_PATH_STYLE	1 when the endpoint needs the bucket in the path rather than the hostname.
S3_FILES_ACCESS_KEY	The access key. Arrives through the secret channel.
S3_FILES_SECRET_KEY	The secret key. Arrives through the secret channel.

#Paths

Name	What it is
WEB_ROOT	Where the live release is inside every container: /var/www/html/current. The directory above it holds every release kept for rollback.
COMPOSER_ROOT	The same directory — where composer.json is.
DRUPAL_ROOT	/var/www/html/current/web, the document root of a Drupal project.
VALLIC_LOG_DIR	/var/log/app, where an application writes log files it wants collected. Anything written here is shipped with the rest of the environment's logs and kept in the machine's own copy. It outlives every release.

#Container images

Name	What it is
MYSQL_DATABASE	What the MariaDB image reads to create the database on first start: the same value as DB_NAME.
MYSQL_USER	The same value as DB_USER, for the MariaDB image.
MYSQL_PASSWORD	The same value as DB_PASSWORD, for the MariaDB image.
MYSQL_ROOT_PASSWORD	The same value as DB_ROOT_PASSWORD, for the MariaDB image.
POSTGRES_DB	The same value as DB_NAME, for the PostgreSQL image.
POSTGRES_USER	The same value as DB_USER, for the PostgreSQL image.
POSTGRES_PASSWORD	The same value as DB_PASSWORD, for the PostgreSQL image.
RABBITMQ_DEFAULT_USER	The same value as RABBITMQ_USER, for the RabbitMQ image.
SOLR_CLOUD_PASSWORD	The same value as SOLR_PASSWORD, for the Solr image: its login, and the digest it signs its ZooKeeper nodes with.
RABBITMQ_DEFAULT_PASS	The same value as RABBITMQ_PASSWORD, for the RabbitMQ image.

Anything beginning VALLIC_ or VC_ is reserved wholesale, so that a variable the platform adds next year cannot collide with one you added today.

#Who reads them

Your variables reach your application: the site's own container, its queue worker and its workers. They do not reach the database, the cache or any other service beside it. Those read only the platform's values above, so a variable you add cannot reconfigure them by sharing a name with one of their settings. The one exception is a variable a service needs from you. For example, OpenSMTPD reads RELAY_PASSWORD to log in to your mail provider.

#What you can change

Every setting the services take, in one place. These are not project variables: they configure the service itself, so they go under that service in vallic.yaml rather than on the Variables page. Service settings says what each one does.

Service	Variables
Go	GOMEMLIMIT, GOMAXPROCS
MariaDB	MYSQL_MAX_ALLOWED_PACKET, MYSQL_INNODB_BUFFER_POOL_SIZE, MYSQL_MAX_CONNECTIONS, MYSQL_SLOW_QUERY_LOG, MYSQL_LONG_QUERY_TIME
Meilisearch	MEILI_MAX_INDEXING_MEMORY, MEILI_LOG_LEVEL
MySQL 8	MYSQL_MAX_ALLOWED_PACKET, MYSQL_INNODB_BUFFER_POOL_SIZE, MYSQL_MAX_CONNECTIONS, MYSQL_SLOW_QUERY_LOG, MYSQL_LONG_QUERY_TIME
Nginx	NGINX_CLIENT_MAX_BODY_SIZE, NGINX_KEEPALIVE_TIMEOUT, NGINX_FASTCGI_READ_TIMEOUT, NGINX_GZIP_COMP_LEVEL, NGINX_STATIC_EXPIRES, NGINX_ERROR_LOG_LEVEL, NGINX_DRUPAL_NOT_FOUND_REGEX, NGINX_WP_NOT_FOUND_REGEX
Node.js	NODE_OPTIONS
OpenSMTPD	RELAY_HOST, RELAY_PORT, RELAY_PROTO, RELAY_USER, OPENSMTPD_MAX_MESSAGE_SIZE, OPENSMTPD_EXPIRE, OPENSMTPD_BOUNCE_WARN
PHP-FPM	PHP_MEMORY_LIMIT, PHP_MAX_EXECUTION_TIME, PHP_POST_MAX_SIZE, PHP_UPLOAD_MAX_FILESIZE, PHP_OPCACHE_MEMORY_CONSUMPTION, PHP_APCU_SHM_SIZE, PHP_FPM_PM_MAX_CHILDREN, PHP_DISPLAY_ERRORS, PHP_MAX_INPUT_VARS
PostgreSQL	POSTGRES_MAX_CONNECTIONS, POSTGRES_SHARED_BUFFERS, POSTGRES_WORK_MEM
RabbitMQ	RABBITMQ_VM_MEMORY_HIGH_WATERMARK
Redis	REDIS_MAXMEMORY_POLICY, REDIS_DATABASES
Solr	SOLR_HEAP, SOLR_MODULES
Valkey	VALKEY_MAXMEMORY_POLICY, VALKEY_DATABASES
Varnish	VARNISHD_PARAM_DEFAULT_TTL, VARNISH_BACKEND_GRACE, VARNISH_CACHE_PER_COUNTRY, VARNISH_MOBILE_SEPARATE_CASH, VARNISH_KEEP_ALL_PARAMS

Set them under the service in vallic.yaml, not as project variables — they configure the service itself rather than your application, and each service page shows the shape.

Anything not listed here is either owned by the platform or decides where a service connects, what it is, or whether it starts. Those are refused on purpose: an application able to set them could break its own environment in ways nothing here would catch.

#Wiring a site to them

Read the environment; commit nothing that differs between environments. For Drupal there is a ready-made settings.vallic.php that does all of it — the database, the cache, the file paths, the hash salt, which Host headers to trust — and is the same file on every project.

#When they take effect

On the next deploy. Changing a variable does not restart anything on its own — the running containers keep the environment they were started with, which is what makes a variable change something you can prepare and then release rather than something that happens under a live site the moment you hit save.

#Next

Storage covers disks, which is the other thing that differs between environments.