# Conflict Between Orbax (nest\_asyncio) and Ray Serve (uvloop) During Checkpointing – Option to Disable uvloop?

**URL:** <https://discuss.ray.io/t/conflict-between-orbax-nest-asyncio-and-ray-serve-uvloop-during-checkpointing-option-to-disable-uvloop/22528>\
**Category:** Ray Serve\
**Created:** [May 20, 2025, 7:44am UTC](https://discuss.ray.io/t/conflict-between-orbax-nest-asyncio-and-ray-serve-uvloop-during-checkpointing-option-to-disable-uvloop/22528 "2025-05-20T07:44:17Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![k\_ajzbss](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/k_ajzbss/32/7979_2.png) [@k\_ajzbss](https://discuss.ray.io/u/k_ajzbss)\
**Post date:** [May 20, 2025, 7:44am UTC](https://discuss.ray.io/t/conflict-between-orbax-nest-asyncio-and-ray-serve-uvloop-during-checkpointing-option-to-disable-uvloop/22528/1 "2025-05-20T07:44:17Z")

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### **1. Severity of the issue: (select one)**

None: I’m just curious or want clarification.  
 Low: Minor issue or workaround available.  
 Medium: Intermittent failures or limited functionality.  
 High: Blocking functionality or affecting production.

### **2. Environment:**

- **Ray version:** 2.41.0
- **Python version:** 3.11
- **OS:** Linux
- **Other relevant libraries/tools:**
  - `orbax` (used for checkpointing)
  - `uvloop` (used with Ray serve)
  - `nest_asyncio` (used internally by Orbax)

### **3. Description of the issue:**

When using **Ray Serve** in combination with **Orbax checkpointers** , there’s a conflict between `nest_asyncio` (used by Orbax) and `uvloop` (used by Ray Serve) when attempting to save a checkpoint.

This issue does **not occur with default Ray** execution (i.e., outside of Serve), where checkpointing works as expected. The incompatibility appears to be related to the event loop, with `uvloop` and `nest_asyncio` being mutually incompatible in some scenarios.

### **4. Question / Feature Request:**

Is there a **flag or configuration option to disable `uvloop`** in Ray Serve or Ray in general, for only some parts of the code, to allow compatibility with libraries like Orbax that rely on `nest_asyncio`?

Alternatively, are there any **recommended workarounds or configurations** for using Orbax checkpointing with Ray Serve that avoid this conflict?

Thank you for your help!!