Chapter 10. Environment variable configuration

Use the QUAY_DISTRIBUTED_STORAGE_PREFERENCE environment variable to set the preferred storage engine for a geo-replicated Red Hat Quay deployment in each region.

Red Hat Quay supports multi-region deployments where multiple instances operate across geographically distributed sites. In these scenarios, each site shares the same configuration and metadata, but storage backends might vary between regions.

To accommodate this, Red Hat Quay allows specifying a preferred storage engine for each deployment using an environment variable. This ensures that while metadata remains synchronized across all regions, each region can use its own optimized storage backend without requiring separate configuration files.

Use the DB_CONNECTION_POOLING environment variable and DB_CONNECTION_ARGS settings to control whether Red Hat Quay pools database connections and the maximum pool size per process.

Database connection pooling is enabled by default, and each process that interacts with the database contains 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 might require analysis to ensure that Red Hat Quay does not exceed the configured database’s maximum connection count.

Overtime, the connection pools release idle connections. To release all connections immediately, Red Hat Quay requires a restart.

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:

# ...
DB_CONNECTION_ARGS:
  max_connections: 10
# ...

$ sudo podman run -d --rm -p 80:8080 -p 443:8443  \
   --name=quay \
   -v $QUAY/config:/conf/stack:Z \
   -v $QUAY/storage:/datastorage:Z \
   -e DB_CONNECTION_POOLING=false
   registry.redhat.io/quay/quay-rhel8:v3.12.1

spec:
  components:
  - kind: quay
    managed: true
    overrides:
      env:
      - name: DB_CONNECTION_POOLING
        value: "false"

Use worker connection count environment variables to limit simultaneous HTTP connections per Red Hat Quay worker process globally or per component. These limits apply either globally or can be scoped to individual components (registry, web UI, or security scanning). By default, each worker process allows up to 50 parallel connections.

This setting is distinct from the number of worker processes.

These connection-related environment variables can be configured differently depending on your deployment type:

WORKER_CONNECTION_COUNT: 10
WORKER_CONNECTION_COUNT_REGISTRY: 10
WORKER_CONNECTION_COUNT_WEB: 10
WORKER_CONNECTION_COUNT_SECSCAN: 10

env:
  - name: WORKER_CONNECTION_COUNT
    value: "10"
  - name: WORKER_CONNECTION_COUNT_REGISTRY
    value: "10"
  - name: WORKER_CONNECTION_COUNT_WEB
    value: "10"
  - name: WORKER_CONNECTION_COUNT_SECSCAN
    value: "10"

Use worker count environment variables to set how many parallel processes handle registry, web UI, and security scanning requests in Red Hat Quay.

If not explicitly set, Red Hat Quay calculates the number of worker processes automatically based on the number of available CPU cores. While this dynamic scaling can optimize performance on larger machines, it might also lead to unnecessary resource usage in smaller environments.

In Red Hat Quay on OpenShift Container Platform deployments, the Operator sets the following default values:

WORKER_COUNT: 10
WORKER_COUNT_REGISTRY: 16
WORKER_COUNT_WEB: 8
WORKER_COUNT_SECSCAN: 4

env:
  - name: WORKER_COUNT
    value: "10"
  - name: WORKER_COUNT_REGISTRY
    value: "16"
  - name: WORKER_COUNT_WEB
    value: "8"
  - name: WORKER_COUNT_SECSCAN
    value: "4"