5. Environment Variables

Debug Logging

Variable	Values	Description
GRK_DEBUG	1 – 5	Enable debug logging. Level 1 provides only error logging; level 3 provides error, warning and information logging; level 5 provides maximum verbosity.

Scheduler

Variable	Values	Description
GRK_EXCALIBUR	(set/unset)	When set, enables the Excalibur scheduling engine (custom high-performance scheduler). When unset, uses the standard scheduling engine.

Cloud Storage / S3

See Cloud Storage for the full list of environment variables. Key variables are summarized below.

AWS Credentials

Variable	Description
AWS_NO_SIGN_REQUEST	YES to skip authentication (public buckets)
AWS_ACCESS_KEY_ID	AWS access key
AWS_SECRET_ACCESS_KEY	AWS secret key
AWS_SESSION_TOKEN	Temporary session token

AWS Region & Endpoint

Variable	Description
AWS_REGION	AWS region (highest precedence)
AWS_DEFAULT_REGION	AWS region (standard SDK variable)
AWS_S3_ENDPOINT	Custom S3 endpoint (for MinIO, R2, etc.)
AWS_HTTPS	YES / NO — use HTTPS
AWS_VIRTUAL_HOSTING	TRUE / FALSE — virtual-hosted style URLs

Grok-Specific AWS Overrides

Variable	Default	Description
GRK_AWS_CREDENTIALS_FILE	~/.aws/credentials	Override credentials file path
GRK_AWS_ROOT_DIR	~/.aws	Override AWS config root directory
GRK_AWS_SSO_ENDPOINT	(auto)	Override SSO endpoint
GRK_AWS_STS_ROOT_URL	(auto)	Override STS endpoint
GRK_AWS_EC2_API_ROOT_URL	http://169.254.169.254	Override EC2 metadata endpoint
GRK_AWS_AUTODETECT_EC2_DISABLE	NO	Set to YES to skip EC2 metadata
GRK_AWS_WEB_IDENTITY_ENABLE	YES	Set to NO to disable web identity

HTTP / Curl

Variable	Description
GRK_CURL_ALLOW_INSECURE	Disable SSL certificate verification
GRK_HTTP_UNSAFESSL	Disable SSL verification
GRK_CURL_TIMEOUT	Request timeout in seconds
GRK_CURL_CACHE_SIZE	Curl buffer size in bytes
GRK_CURL_NON_CACHED	Prefixes to disable connection reuse for
GRK_CURL_PROXY	Proxy URL
GRK_CURL_PROXYUSERPWD	Proxy credentials (user:password)
GRK_CURL_PROXYAUTH	Proxy auth type