Repository: node
Issue: Cannot set up `cluster.schedulingPolicy` in ESM
Labels: cluster

### Version

v18.17.1

### Platform

Linux xxx 6.2.0-26-generic #26~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Jul 13 16:27:29 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

### Subsystem

cluster

### What steps will reproduce the bug?

Run the following code in Node.js:

```js
import * as cluster from 'cluster'

if (cluster.isPrimary) { 
    process.env.NODE_CLUSTER_SCHED_POLICY = 'none'
    console.log(`process.env.NODE_CLUSTER_SCHED_POLICY: ${process.env.NODE_CLUSTER_SCHED_POLICY}`)
    for (let index = 0; index < 2; index++) { 
        cluster.fork()
        setTimeout(() => console.log(`cluster.schedulingPolicy: ${cluster.schedulingPolicy}`), 1000)
    }
} else { 
    setTimeout(() => null, 1000)
}
```

[cluster-error.txt](https://github.com/nodejs/node/files/12385479/cluster-error.txt)
Attached as `cluster-error.txt`. You will see that it prints the following:

```console
$ node cluster-error.js 
process.env.NODE_CLUSTER_SCHED_POLICY: 'none'
cluster.schedulingPolicy: 2
cluster.schedulingPolicy: 2
```

So the env variable `NODE_CLUSTER_SCHED_POLICY` has no effect, `cluster.schedulingPolicy` has the value `2` which is the default `cluster.SCHED_RR`. However running it with the env variable from the console works as expected:

```console
$ NODE_CLUSTER_SCHED_POLICY='none' node cluster-error.js 
process.env.NODE_CLUSTER_SCHED_POLICY: none
cluster.schedulingPolicy: 1
cluster.schedulingPolicy: 1
```

I cannot set the `cluster.schedulingPolicy` as per [the docs](https://nodejs.org/api/cluster.html#cluster_cluster_schedulingpolicy): `cluster.schedulingPolicy = cluster.SCHED_NONE` since the cluster module is `import`ed:

```js
import * as cluster from 'cluster'
cluster.schedulingPolicy = cluster.SCHED_NONE
```

so I get a `TypeError`:

```console
cluster.schedulingPolicy = cluster.SCHED_NONE
                         ^

TypeError: Cannot assign to read only property 'schedulingPolicy' of object '[object Module]'
    at file:///home/alex/projects/loadtest/cluster-error.js:2:26
    at ModuleJob.run (node:internal/modules/esm/module_job:194:25)
```

### How often does it reproduce? Is there a required condition?

With the attached code it works (as in doesn't work) always.

### What is the expected behavior? Why is that the expected behavior?

I expect to see the same output as with the env variable `NODE_CLUSTER_SCHED_POLICY='none'`, i.e. the `cluster.schedulingPolicy` is set to 1 `cluster.SCHED_NONE`:

```console
$ node cluster-error.js 
process.env.NODE_CLUSTER_SCHED_POLICY: none
cluster.schedulingPolicy: 1
cluster.schedulingPolicy: 1
```

(Fake output.)

### What do you see instead?

Instead I see `cluster.schedulingPolicy` has the default value of 2 `cluster.SCHED_RR`:

```console
$ node cluster-error.js 
process.env.NODE_CLUSTER_SCHED_POLICY: none
cluster.schedulingPolicy: 2
cluster.schedulingPolicy: 2
```

### Additional information

I am the author of the [loadtest package](https://www.npmjs.com/package/loadtest) and I am converting it to multi-core. I really see a big difference of more than 30% when running the test server in the default round-robin mode and in the `none` mode I want to set:

* `cluster.SCHED_RR`: 9600 rps.
* `cluster.SCHED_NONE`: 12700 rps.

It is true that load on processors is a bit more uneven in `none`, but that doesn't seem to matter much. I want my lightning fast speed! :zap: 

Besides, I think that the documentation should be updated because the recommended way of setting `cluster.schedulingPolicy` does not work. I would think that the best solution is to have a setting in [`cluster.settings`](https://nodejs.org/api/cluster.html#clustersettings) that can be set with [`cluster.setupPrimary([settings])`](https://nodejs.org/api/cluster.html#clustersetupprimarysettings). As suggested by @bnoordhuis in [this hopeful comment](https://github.com/nodejs/node/blob/78842cf213aea95a64119b18b036d0255507438c/lib/internal/cluster/primary.js#L47).