# Share one instance across a cluster

Prerequisites: [dynamic linking](../intermediate/dynamic-linking.md) and
[permissions](../intermediate/permissions.md). A named cluster groups dynamic
conduits for `unique_per_conduit_cluster` resolution.

The saved cluster lesson remains **Intermediate 25**, its original location.
Its topic belongs here as well, so both guides point to the same lesson.

## Establish the sharing structure

The example binds a cluster bus with `create` permissions, conjures two named
conduits, and links them. It creates the cluster through the cloud, adds the owner,
elects the owner as leader, and then adds the second member.

Leader election matters: the shared creations store belongs to the cluster, and it is
served only while a leader is elected. Membership alone does not serve it. A leader
change keeps the shared object, and deleting the cluster disposes it. Links matter
too: the sharing contracts use the relationship between the conduits.

The final assertion checks that both members resolve the **same bus object**.
Use that identity check when adapting the pattern, not merely the membership list.


## The workflow in code

These are the core steps from the saved example. Use its complete linked script for all class definitions and setup.

```{literalinclude} ../downloads/02_intermediate/25_clusters_unique_per_cluster.py
:language: python
:pyobject: main
:linenos:
```


## Runnable examples

- [Clusters unique per cluster](../examples/intermediate/25-clusters-unique-per-cluster.md) — Intermediate 25

[All advanced examples](../examples/advanced/index.md) · [Level contents](index.md) · [Full contents](../contents.md)

[Canonical page source](https://github.com/Synaptic724/melder/blob/0895ce795453cd87e35d70665957b4e89aad3317/docs/advanced/clusters.md)