Configuration

LocalStack exposes various configuration options to control its behaviour.

With lstk, these options can be passed as LOCALSTACK_-prefixed environment variables when starting the container:

LOCALSTACK_DEBUG=1 lstk start

Alternatively, set them as named environment profiles in your config file and reference them from the container block:

.lstk/config.toml

[[containers]]
type = "snowflake"
env  = ["debug"]

[env.debug]
DEBUG = "1"

lstk start

See Passing environment variables to the container for details.

Core

Options that affect the core Snowflake emulator functionality.

Variable	Example Values	Description
DEBUG	0 (default) | 1	Flag to increase log level and print more verbose logs (useful for troubleshooting issues)
SF_LOG	trace	Specify the log level. Currently overrides the DEBUG configuration. trace for detailed request/response
SF_S3_ENDPOINT	s3.localhost.localstack.cloud:4566 (default)	Specify the S3 endpoint to use for the Snowflake emulator.
SF_S3_ENDPOINT_EXTERNAL	s3.localhost.localstack.cloud:4566	S3 endpoint for file uploads to return to external clients. Defaults to SF_S3_ENDPOINT if not set.
SF_AWS_ENDPOINT_URL	localhost:4566 (default)	AWS services endpoint for connecting to other AWS services (SQS, SNS, etc.) from the Snowflake emulator.
DNS_NAME_PATTERNS_TO_RESOLVE_UPSTREAM	*.s3.amazonaws.com (example)	List of domain names that should NOT be resolved to the LocalStack container, but instead always forwarded to the upstream resolver (S3 for example). this would be required when importing data into a stage from an external S3 bucket on the real AWS cloud. Comma-separated list of Python-flavored regex patterns.
SF_HOSTNAMES	snowflake.localhost.localstack.cloud,snowflake.internal	Comma-separated list of hostnames that should route to the Snowflake emulator. If set, only these hostnames are matched. If unset, LocalStack also matches any hostname with a snowflake. subdomain (i.e., *snowflake.* or *.snowflake.*) for backward compatibility.
SF_CSV_IMPORT_MAX_ROWS	50000 (default)	Maximum number of rows to import from CSV files into tables
SF_DEFAULT_USER	test (default)	Specify the default user to be used by the Snowflake emulator.
SF_DEFAULT_PASSWORD	test (default)	Specify the default password to be used by the Snowflake emulator.

Custom Snowflake hostnames

By default, the Snowflake emulator accepts requests for hostnames such as snowflake.localhost.localstack.cloud and other *.snowflake.* hostnames. If you expose the emulator through a custom DNS name, for example in Kubernetes or behind an ingress, set SF_HOSTNAMES to the exact hostnames clients use to reach the emulator. When you use lstk, add the LOCALSTACK_ prefix so the CLI passes the variable to the container:

LOCALSTACK_SF_HOSTNAMES=snowflake.internal.example.com,snowflake.internal,snowflake.localhost.localstack.cloud \
lstk start

The first hostname in SF_HOSTNAMES is used as the primary hostname for local connection defaults and generated URLs. When SF_HOSTNAMES is set, the default wildcard fallback is disabled, and only the configured hostnames are routed to the Snowflake emulator. Include snowflake.localhost.localstack.cloud in the list, as shown above, if you want the default hostname to continue working.

SF_HOSTNAMES controls Host-header routing only. It does not configure DNS or TLS for custom hostnames. Configure each hostname to resolve to the LocalStack host from every client that connects to the emulator. For example, add the following entries to the client’s /etc/hosts file when LocalStack runs on the same machine:

/etc/hosts

127.0.0.1 snowflake.internal.example.com
127.0.0.1 snowflake.internal

The default LocalStack certificate does not match custom domains. Configure a matching custom TLS certificate before connecting through a custom hostname.

Caution

Do not use insecure_mode=True in the Snowflake Connector for Python to work around a certificate hostname mismatch. This deprecated option disables certificate revocation checks, but the connector still verifies the certificate and hostname.

Note

SF_HOSTNAME_REGEX is no longer supported. If you previously used SF_HOSTNAME_REGEX, migrate to SF_HOSTNAMES and list each hostname explicitly.

If your custom hostname also needs a matching TLS certificate, use LocalStack’s standard certificate configuration options:

LOCALSTACK_SF_HOSTNAMES=snowflake.internal.example.com \
CUSTOM_SSL_CERT_PATH=/var/lib/localstack/custom/cert.pem \
SKIP_SSL_CERT_DOWNLOAD=1 \
lstk start

The file referenced by CUSTOM_SSL_CERT_PATH must contain a certificate and private key that match the hostname used by your Snowflake clients. For more general guidance on adding trusted certificates to LocalStack, see Custom TLS certificates.

CLI

lstk is configured through its config file rather than through environment variables. See Configuration on the lstk page for the config file search order, the field reference, and how to define named environment profiles.

Docker

Options to configure how LocalStack interacts with Docker.

Variable	Example Values	Description
LOCALSTACK_VOLUME_DIR	~/.cache/localstack/volume (on Linux)	The location on the host of the LocalStack volume directory mount.
DOCKER_FLAGS		Allows to pass custom flags (e.g., volume mounts) to “docker run” when running LocalStack in Docker.
DOCKER_SOCK	/var/run/docker.sock	Path to local Docker UNIX domain socket
DOCKER_BRIDGE_IP	172.17.0.1	IP of the Docker bridge used to enable access between containers
LEGACY_DOCKER_CLIENT	0|1	Whether LocalStack should use the command-line Docker client and subprocess execution to run Docker commands, rather than the Docker SDK.
DOCKER_CMD	docker (default), sudo docker	Shell command used to run Docker containers (only used in combination with LEGACY_DOCKER_CLIENT)
FORCE_NONINTERACTIVE		When running with Docker, disables the --interactive and --tty flags. Useful when running headless.