Chapter 3. Environment variables
Red Hat Quay supports a limited number of environment variables for dynamic configuration.
3.1. Geo-replication
The exact same configuration should be used across all regions, with exception of the storage backend, which can be configured explicitly using the QUAY_DISTRIBUTED_STORAGE_PREFERENCE environment variable.
| Variable | Type | Description |
|---|---|---|
| QUAY_DISTRIBUTED_STORAGE_PREFERENCE | String | The preferred storage engine (by ID in DISTRIBUTED_STORAGE_CONFIG) to use. |
3.2. Database connection pooling
Red Hat Quay is composed of many different processes which all run within the same container. Many of these processes interact with the database.
If enabled, each process that interacts with the database will contain a connection pool. These per-process connection pools are configured to maintain a maximum of 20 connections. Under heavy load, it is possible to fill the connection pool for every process within a Red Hat Quay container. Under certain deployments and loads, this may require analysis to ensure Red Hat Quay does not exceed the database’s configured maximum connection count.
Overtime, the connection pools will release idle connections. To release all connections immediately, Red Hat Quay requires a restart.
Database connection pooling may be toggled by setting the environment variable DB_CONNECTION_POOLING={true|false}
| Variable | Type | Description |
|---|---|---|
| DB_CONNECTION_POOLING | Boolean | Enable or disable database connection pooling |
If database connection pooling is enabled, it is possible to change the maximum size of the connection pool. This can be done through the following config.yaml option:
config.yaml
... DB_CONNECTION_ARGS: max_connections: 10 ...
3.3. HTTP connection counts
It is possible to specify the quantity of simultaneous HTTP connections using environment variables. These can be specified as a whole, or for a specific component. The default for each is 50 parallel connections per process.
| Variable | Type | Description |
|---|---|---|
| WORKER_CONNECTION_COUNT | Number |
Simultaneous HTTP connections |
| WORKER_CONNECTION_COUNT_REGISTRY | Number |
Simultaneous HTTP connections for registry |
| WORKER_CONNECTION_COUNT_WEB | Number |
Simultaneous HTTP connections for web UI |
| WORKER_CONNECTION_COUNT_SECSCAN | Number |
Simultaneous HTTP connections for Clair |
3.4. Worker count variables
| Variable | Type | Description |
|---|---|---|
| WORKER_COUNT | Number | Generic override for number of processes |
| WORKER_COUNT_REGISTRY | Number |
Specifies the number of processes to handle Registry requests within the |
| WORKER_COUNT_WEB | Number |
Specifies the number of processes to handle UI/Web requests within the container |
| WORKER_COUNT_SECSCAN | Number |
Specifies the number of processes to handle Security Scanning (e.g. Clair) integration within the container |
