# Configuring Dendrite (optional)

By default, this playbook configures the [Synapse](https://github.com/element-hq/synapse) Matrix server, but you can also use [Dendrite](https://github.com/matrix-org/dendrite).

**Notes**:

- **You can't switch an existing Matrix server's implementation** (e.g. Synapse -> Dendrite). Proceed below only if you're OK with losing data or you're dealing with a server on a new domain name, which hasn't participated in the Matrix federation yet.

- **homeserver implementations other than Synapse may not be fully functional**. The playbook may also not assist you in an optimal way (like it does with Synapse). Make yourself familiar with the downsides before proceeding

The playbook provided settings for Dendrite are defined in [`roles/custom/matrix-dendrite/defaults/main.yml`](../roles/custom/matrix-dendrite/defaults/main.yml) and they ultimately end up in the generated `/matrix/dendrite/config/dendrite.yaml` file (on the server). This file is generated from the [`roles/custom/matrix-dendrite/templates/dendrite/dendrite.yaml.j2`](../roles/custom/matrix-dendrite/templates/dendrite/dendrite.yaml.j2) template.

**If there's an existing variable** which controls a setting you wish to change, you can simply define that variable in your configuration file (`inventory/host_vars/matrix.<your-domain>/vars.yml`) and [re-run the playbook](installing.md) to apply the changes.

Alternatively, **if there is no pre-defined variable** for a Dendrite setting you wish to change:

- you can either **request a variable to be created** (or you can submit such a contribution yourself). Keep in mind that it's **probably not a good idea** to create variables for each one of Dendrite's various settings that rarely get used.

- or, you can **extend and override the default configuration** ([`dendrite.yaml.j2`](../roles/custom/matrix-dendrite/templates/dendrite/dendrite.yaml.j2)) by making use of the `matrix_dendrite_configuration_extension_yaml` variable. You can find information about this in [`roles/custom/matrix-dendrite/defaults/main.yml`](../roles/custom/matrix-dendrite/defaults/main.yml).

- or, if extending the configuration is still not powerful enough for your needs, you can **override the configuration completely** using `matrix_dendrite_configuration` (or `matrix_dendrite_configuration_yaml`). You can find information about this in [`roles/custom/matrix-dendrite/defaults/main.yml`](../roles/custom/matrix-dendrite/defaults/main.yml).



## Installation

To use Dendrite, you **generally** need the following additional `vars.yml` configuration:

```yaml
matrix_homeserver_implementation: dendrite
```
