# Picking a specific python version when building ray locally

**URL:** <https://discuss.ray.io/t/picking-a-specific-python-version-when-building-ray-locally/4081>\
**Category:** Ray Client\
**Created:** [November 10, 2021, 5:36am UTC](https://discuss.ray.io/t/picking-a-specific-python-version-when-building-ray-locally/4081 "2021-11-10T05:36:36Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Cherif\_Jazra](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/cherif_jazra/32/1679_2.png) [@Cherif\_Jazra](https://discuss.ray.io/u/Cherif_Jazra)\
**Post date:** [November 10, 2021, 5:36am UTC](https://discuss.ray.io/t/picking-a-specific-python-version-when-building-ray-locally/4081/1 "2021-11-10T05:36:36Z")

</div>

I’m running into a version mismatch for a ray cluster I built with [Building Ray from Source — Ray v1.8.0](https://docs.ray.io/en/latest/development.html#building-ray-on-linux-macos-full)  
where after I start the server in java, and I’m getting

```auto
<class 'RuntimeError'>: Version mismatch: The cluster was started with:
    Ray: 1.7.1
    Python: 3.8.5
This process on node 192.168.201.34 was started with:
    Ray: 1.7.1
    Python: 3.9.7

```

How do I build the ray cluster locally with a specific python version such such that I can create jars with the expected python version? I am using `build-jar-multiplatform.sh` to create the jars

note that when I built the project locally, there is a `ray` binary created inside the python environment `bin` folder, and starting the cluster with this binary (`ray start..`) works.