# Overriding parameters

The `with_overrides` method allows you to specify parameter overrides on [tasks](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/_index),
[subworkflows, and sub-launch plans](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/workflows/subworkflows-and-sub-launch-plans) at execution time.
This is useful when you want to change the behavior of a task, subworkflow, or sub-launch plan without modifying the original definition.

## Task parameters

When calling a task, you can specify the following parameters in `with_overrides`:

* `accelerator`: Specify [accelerators](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-hardware-environment/accelerators).
* `cache_serialize`: Enable [cache serialization](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/caching).
* `cache_version`: Specify the [cache version](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/caching).
* `cache`: Enable [caching](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/caching).
* `container_image`: Specify a [container image](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-software-environment/image-spec).
* `interruptible`: Specify whether the task is [interruptible](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-hardware-environment/interruptible-instances).
* `limits`: Specify [resource limits](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-hardware-environment/customizing-task-resources).
* `name`: Give a specific name to this task execution. This will appear in the workflow flowchart in the UI (see [below](#using-with_overrides-with-name-and-node_name)).
* `node_name`: Give a specific name to the DAG node for this task. This will appear in the workflow flowchart in the UI (see [below](#using-with_overrides-with-name-and-node_name)).
* `requests`: Specify [resource requests](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-hardware-environment/customizing-task-resources).
* `retries`: Specify the [number of times to retry this task](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-parameters).
* `task_config`: Specify a [task config](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-parameters).
* `timeout`: Specify the [task timeout](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/tasks/task-parameters).

For example, if you have a task that does not have caching enabled, you can use `with_overrides` to enable caching at execution time as follows:

```python
my_task(a=1, b=2, c=3).with_overrides(cache=True)
```

### Using `with_overrides` with `name` and `node_name`

Using `with_overrides` with `name` on a task is a particularly useful feature.
For example, you can use `with_overrides(name="my_task")` to give a specific name to a task execution, which will appear in the UI.
The name specified can be chosen or generated at invocation time without modifying the task definition.

```python
@union.workflow
def wf() -> int:
    my_task(a=1, b=1, c=1).with_overrides(name="my_task_1")
    my_task(a=2, b=2, c=2).with_overrides(name="my_task_2", node_name="my_node_2")
    return my_task(a=1, b=1, c=1)
```

The above code would produce the following workflow display in the UI:

![Overriding name](https://www.union.ai/docs/v1/union/user-guide/_static/images/user-guide/development-cycle/overriding-parameters/override-name.png)

There is also a related parameter called `node_name` that can be used to give a specific name to the DAG node for this task.
The DAG node name is usually autogenerated as `n0`, `n1`, `n2`, etc. It appears in the `node` column of the workflow table.
Overriding `node_name` results in the autogenerated name being replaced by the specified name:

![Overriding node name](https://www.union.ai/docs/v1/union/user-guide/_static/images/user-guide/development-cycle/overriding-parameters/override-node-name.png)

Note that the `node_name` was specified as `my_node_2` in the code but appears as `my_node_2` in the UI. This is to the fact that Kubernetes node names cannot contain underscores. Union.ai automatically alters the name to be Kubernetes-compliant.

## Subworkflow and sub-launch plan parameters

When calling a workflow or launch plan from within a high-level workflow
(in other words, when invoking a subworkflow or sub-launch plan),
you can specify the following parameters in `with_overrides`:

* `cache_serialize`: Enable [cache serialization](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/caching).
* `cache_version`: Specify the [cache version](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/caching).
* `cache`: Enable [caching](https://www.union.ai/docs/v1/union/user-guide/development-cycle/core-concepts/caching).

---
**Source**: https://github.com/unionai/unionai-docs/blob/main/content/user-guide/development-cycle/overriding-parameters.md
**HTML**: https://www.union.ai/docs/v1/union/user-guide/development-cycle/overriding-parameters/