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1258baeb7f
* fn: agent eviction revisited
Previously, the hot-container eviction logic used
number of waiters of cpu/mem resources to decide to
evict a container. An ejection ticker used to wake up
its associated container every 1 sec to reasses system
load based on waiter count. However, this does not work
for non-blocking agent since there are no waiters for
non-blocking mode.
Background on blocking versus non-blocking agent:
*) Blocking agent holds a request until the
the request is serviced or client times out. It assumes
the request can be eventually serviced when idle
containers eject themselves or busy containers finish
their work.
*) Non-blocking mode tries to limit this wait time.
However non-blocking agent has never been truly
non-blocking. This simply means that we only
make a request wait if we take some action in
the system. Non-blocking agents are configured with
a much higher hot poll frequency to make the system
more responsive as well as to handle cases where an
too-busy event is missed by the request. This is because
the communication between hot-launcher and waiting
requests are not 1-1 and lossy if another request
arrives for the same slot queue and receives a
too-busy response before the original request.
Introducing an evictor where each hot container can
register itself, if it is idle for more than 1 seconds.
Upon registry, these idle containers become eligible
for eviction.
In hot container launcher, in non-blocking mode,
before we attempt to emit a too-busy response, now
we attempt an evict. If this is successful, then
we wait some more. This could result in requests
waiting for more than they used to only if a
container was evicted. For blocking-mode, the
hot launcher uses hot-poll period to assess if
a request has waited for too long, then eviction
is triggered.
73 lines
5.1 KiB
Markdown
73 lines
5.1 KiB
Markdown
# Fn Runtime Options
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## Default run command for production
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This will run with docker in docker.
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```sh
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docker run --privileged --rm --name fns -it -v $PWD/data:/app/data -p 80:8080 fnproject/fnserver
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```
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See below for starting without docker in docker.
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## Configuration
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When starting Fn, you can pass in the following configuration variables as environment variables. Use `-e VAR_NAME=VALUE` in
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docker run. For example:
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```sh
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docker run -e VAR_NAME=VALUE ...
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```
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| Env Variables | Description | Default values |
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| `FN_DB_URL` | The database URL to use in URL format. See [Databases](databases/README.md) for more information. | sqlite3:///app/data/fn.db |
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| `FN_MQ_URL` | The message queue to use in URL format. See [Message Queues](mqs/README.md) for more information. | bolt:///app/data/worker_mq.db |
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| `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 |
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| `FN_PORT `| Sets the port to run on | 8080 |
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| `FN_LOG_LEVEL` | Set to DEBUG to enable debugging | INFO |
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| `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 }
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| `FN_LOG_PREFIX` | If supplying a syslog url in `FN_LOG_DEST`, a prefix to add to each log line
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| `FN_API_CORS_ORIGINS` | A comma separated list of URLs to enable [CORS](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS) for (or `*` for all domains). This corresponds to the allowed origins in the `Acccess-Control-Allow-Origin` header. | None |
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| `FN_API_CORS_HEADERS` | A comma separated list of Headers to enable [CORS](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS) for. This corresponds to the allowed headers in the `Access-Control-Allow-Headers` header. | Origin,Content-Length,Content-Type |
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| `FN_FREEZE_IDLE_MSECS` | Set this option to specify the amount of time to wait in milliseconds before pausing/freezing an idle hot container. Set to 0 to freeze idle containers without any delay. Set to negative integer to disable freeze/pause of idle hot containers. | 50 |
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| `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 |
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| `FN_MAX_RESPONSE_SIZE` | Set this option to specify the http body or json response size in bytes from the containers. | 0 (off) |
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| `DOCKER_HOST` | Docker remote API URL. | /var/run/docker.sock |
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| `DOCKER_API_VERSION` | Docker remote API version. | 1.24 |
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| `DOCKER_TLS_VERIFY` | Set this option to enable/disable Docker remote API over TLS/SSL. | 0 |
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| `DOCKER_CERT_PATH` | Set this option to specify where CA cert placeholder. | ~/.docker/cert.pem |
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| `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](https://docs.docker.com/engine/reference/commandline/run/#set-storage-driver-options-per-container) documentation for details. | None |
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| `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 |
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| `FN_DISABLE_READONLY_ROOTFS` | Set this option to enable writable root filesystem. By default root filesystem is mounted read-only. | None |
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| `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](https://docs.docker.com/engine/reference/commandline/save/). | None |
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## Starting without Docker in Docker
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The default way to run Fn, as it is in the Quickstart guide, is to use docker-in-docker (dind). There are
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a couple reasons why we did it this way:
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* It's clean. Once the container exits, there is nothing left behind including all the function images.
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* 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.
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There are some reasons you may not want to use dind, such as using the image cache during testing or you're running
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[Windows](windows.md).
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### Mount the Host Docker
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One way is to mount the host Docker. Everything is essentially the same except you add a `-v` flag:
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```sh
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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
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```
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On Linux systems where SELinux is enabled and set to "Enforcing", SELinux will stop the container from accessing
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the host docker and the local directory mounted as a volume, so this method cannot be used unless security restrictions
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are disabled.
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### Run outside Docker
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You can of course just run the binary directly, you'll just have to change how you set the environment variables above.
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See [contributing doc](../CONTRIBUTING.md) for information on how to build and run.
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