Fn Runtime Options

Default run command for production

This will run with docker in docker.

docker run --privileged \
  --rm \
  --name fns \
  -it \
  -v $PWD/data:/app/data \
  -v $PWD/data/iofs:/iofs \
  -e "FN_IOFS_DOCKER_PATH=$PWD/data/iofs" \
  -e "FN_IOFS_PATH=/iofs" \
  -p 80:8080 \
  fnproject/fnserver

See below for starting without docker in docker.

Configuration

When starting Fn, you can pass in the following configuration variables as environment variables. Use -e VAR_NAME=VALUE in docker run. For example:

docker run -e VAR_NAME=VALUE ...

Additionally you may desire to load the environment variables from files, for example if you are using Docker Secrets, in that case you may append _FILE to the end of any variable name and specify the file location. The variable will be filled with the file's contents. For example:

docker run -e VAR_NAME_FILE=/path/to/secret ...

Env Variables	Description	Default values
FN_DB_URL	The database URL to use in URL format. See Databases for more information.	sqlite3:///app/data/fn.db
FN_MQ_URL	The message queue to use in URL format. See Message Queues for more information.	bolt:///app/data/worker_mq.db
FN_API_URL	The primary Fn API URL to that this instance will talk to. In a production environment, this would be your load balancer URL.	N/A
FN_PORT	Sets the port to run on	8080
FN_LOG_LEVEL	Set to DEBUG to enable debugging	INFO
FN_LOG_DEST	Set a url to send logs to, instead of stderr. [scheme://][host][:port][/path]; default scheme to udp:// if none given, possible schemes: { udp, tcp, file }
FN_LOG_PREFIX	If supplying a syslog url in FN_LOG_DEST, a prefix to add to each log line
FN_API_CORS_ORIGINS	A comma separated list of URLs to enable CORS for (or * for all domains). This corresponds to the allowed origins in the Acccess-Control-Allow-Origin header.	None
FN_API_CORS_HEADERS	A comma separated list of Headers to enable CORS for. This corresponds to the allowed headers in the Access-Control-Allow-Headers header.	Origin,Content-Length,Content-Type
FN_FREEZE_IDLE_MSECS	Set this option to specify the amount of time to wait in milliseconds before pausing/freezing an idle container. Set to 0 to freeze idle containers without any delay. Set to negative integer to disable freeze/pause of idle hot containers.	50
FN_EJECT_IDLE_MSECS	Set this option to specify the amount of time in milliseconds for an idle hot container to become eligible for eviction if the system is starved for CPU and Memory resources. Set to negative integer to disable this feature.	1000
FN_MAX_RESPONSE_SIZE	Set this option to specify the http body or json response size in bytes from the containers.	0 (off)
DOCKER_HOST	Docker remote API URL.	/var/run/docker.sock
DOCKER_API_VERSION	Docker remote API version.	1.24
DOCKER_TLS_VERIFY	Set this option to enable/disable Docker remote API over TLS/SSL.	0
DOCKER_CERT_PATH	Set this option to specify where CA cert placeholder.	~/.docker/cert.pem
FN_MAX_FS_SIZE_MB	Set this option in MB to pass a size option to Docker storage driver. This limits the file system size for all containers on the system. See Docker storage driver options per container documentation for details.	None
FN_DOCKER_NETWORKS	Set this option with a list of docker networks for function containers to use. If unset, default docker network is used.	None
FN_DISABLE_READONLY_ROOTFS	Set this option to enable writable root filesystem. By default root filesystem is mounted read-only.	None
FN_DOCKER_LOAD_FILE	Set this option with an absolute path to a tarball to load a set of docker images during fn server startup. The tarball can be generated using docker save.	None

Starting without Docker in Docker

The default way to run Fn, as it is in the Quickstart guide, is to use docker-in-docker (dind). There are a couple reasons why we did it this way:

• It's clean. Once the container exits, there is nothing left behind including all the function images.
• You can set resource restrictions for the entire Fn instance. For instance, you can set --memory on the docker run command to set the max memory for the Fn instance AND all of the functions it's running.

There are some reasons you may not want to use dind, such as using the image cache during testing or you're running Windows.

Mount the Host Docker

One way is to mount the host Docker. Everything is essentially the same except you add a -v flag:

docker run --rm --name functions -it -v /var/run/docker.sock:/var/run/docker.sock -v $PWD/data:/app/data -p 8080:8080 fnproject/fnserver

On Linux systems where SELinux is enabled and set to "Enforcing", SELinux will stop the container from accessing the host docker and the local directory mounted as a volume, so this method cannot be used unless security restrictions are disabled.

Run outside Docker

You can of course just run the binary directly, you'll just have to change how you set the environment variables above.

See contributing doc for information on how to build and run.