Run, build, and deploy functions#

In this section


There is a set of methods used to deploy and run project functions. They can be used interactively or inside a pipeline (e.g. Kubeflow). When used inside a pipeline, each method is automatically mapped to the relevant pipeline engine command.

  • run_function() — Run a local or remote task as part of local or remote batch/scheduled task

  • build_function() — deploy an ML function, build a container with its dependencies for use in runs

  • deploy_function() — deploy real-time/online (nuclio or serving based) functions

You can use those methods as project methods, or as global (mlrun.) methods. For example:

# run the "train" function in myproject
run = myproject.run_function("train", inputs={"data": data_url})  

# run the "train" function in the current/active project (or in a pipeline)
run = mlrun.run_function("train", inputs={"data": data_url})  

The first parameter in all three methods is either the function name (in the project), or a function object, used if you want to specify functions that you imported/created ad hoc, or to modify a function spec. For example:

# import a serving function from the Function Hub and deploy a trained model over it
serving = import_function("hub://v2_model_server", new_name="serving")
serving.spec.replicas = 2
deploy = deploy_function(
    models=[{"key": "mymodel", "model_path": train.outputs["model"]}],

You can use the get_function() method to get the function object and manipulate it, for example:

trainer = project.get_function("train")
trainer.with_limits(mem="2G", cpu=2, gpus=1)
run = project.run_function("train", inputs={"data": data_url}) 


Use the run_function() method to run a local or remote batch/scheduled task. The run_function method accepts various parameters such as name, handler, params, inputs, schedule, etc. Alternatively, you can pass a Task object (see: new_task()) that holds all of the parameters and the advanced options.

Functions can host multiple methods (handlers). You can set the default handler per function. You need to specify which handler you intend to call in the run command. You can pass parameters (arguments) or data inputs (such as datasets, feature-vectors, models, or files) to the functions through the run_function method.

The run_function() command returns an MLRun RunObject object that you can use to track the job and its results. If you pass the parameter watch=True (default), the command blocks until the job completes.

MLRun also supports iterative jobs that can run and track multiple child jobs (for hyperparameter tasks, AutoML, etc.). See Hyperparameter tuning optimization for details and examples.

Read further details on running tasks and getting their results.

Usage examples:

# create a project with two functions (local and from Function Hub)
project = mlrun.new_project(project_name, "./proj")
project.set_function("", "prep", image="mlrun/mlrun")
project.set_function("hub://auto_trainer", "train")

# run functions (refer to them by name)
run1 = project.run_function("prep", params={"x": 7}, inputs={'data': data_url})
run2 = project.run_function("train", inputs={"dataset": run1.outputs["data"]})

Run/simulate functions locally:

Functions can also run and be debugged locally by using the local runtime or by setting the local=True parameter in the run() method (for batch functions).


The build_function() method is used to deploy an ML function and build a container with its dependencies for use in runs.


# build the "trainer" function image (based on the specified requirements and code repo)

The build_function() method accepts different parameters that can add to, or override, the function build spec. You can specify the target or base image extra docker commands, builder environment, and source credentials (builder_env), etc.

See further details and examples in Build function image.


The deploy_function() method is used to deploy real-time/online (nuclio or serving) functions and pipelines. Read more about Real-time serving pipelines.

Basic example:

# Deploy a real-time nuclio function ("myapi")
deployment = project.deploy_function("myapi")

# invoke the deployed function (using HTTP request) 
resp = deployment.function.invoke("/do")

You can provide the env dict with: extra environment variables; models list to specify specific models and their attributes (in the case of serving functions); builder environment; and source credentials (builder_env).

Example of using deploy_function inside a pipeline, after the train step, to generate a model:

# Deploy the trained model (from the "train" step) as a serverless serving function
serving_fn = mlrun.new_function("serving", image="mlrun/mlrun", kind="serving")
            "key": model_name,
            "model_path": train.outputs["model"],
            "class_name": 'mlrun.frameworks.sklearn.SklearnModelServer',


If you want to create a simulated (mock) function instead of a real Kubernetes service, set the mock flag is set to True. See deploy_function api.

Default image#

You can set a default image for the project. This image will be used for deploying and running any function that does not have an explicit image assigned, and replaces MLRun’s default image of mlrun/mlrun. To set the default image use the set_default_image() method with the name of the image.

The default image is applied to the functions in the process of enriching the function prior to running or deploying. Functions will therefore use the default image set in the project at the time of their execution, not the image that was set when the function was added to the project.

For example:

project = mlrun.new_project(project_name, "./proj")
# use v1 of a pre-built image as default
# set function without an image, will use the project's default image
project.set_function("", "prep")

# function will run with the "myrepo/my-prebuilt-image:v1" image
run1 = project.run_function("prep", params={"x": 7}, inputs={'data': data_url})


# replace the default image with a newer v2
# function will now run using the v2 version of the image 
run2 = project.run_function("prep", params={"x": 7}, inputs={'data': data_url})