# Installing and Updating an Extension

Redis supports <span class="s2">**modules**</span> to extend core functionality with new data types, commands, or algorithms. These modules behave like plugins in other systems and are loaded at server startup. Examples include [RedisBloom](https://oss.redis.com/redisbloom/), [RedisTimeSeries](https://oss.redis.com/redistimeseries/), [RedisJSON](https://oss.redis.com/redisjson/), and [RedisSearch](https://oss.redis.com/redisearch/).

In Elestio-hosted Redis instances or any Docker Compose-based setup, modules can be loaded by specifying them in the service configuration. This guide walks through how to install, load, and manage Redis modules using Docker Compose, along with common issues and best practices.

## **Installing and Enabling Redis Modules**

Redis modules are typically compiled as shared object (<span class="s3">.so</span>) files and must be loaded at server startup using the `<span class="s3">--loadmodule</span>` option. These module files are mounted into the container and referenced from within the container’s file system. To use a module like RedisBloom in a Docker Compose setup:

#### **Update docker-compose.yml**

Mount the module file into the container and load it:

```yaml
services:
  redis:
    image: redis/redis-stack-server:latest
    volumes:
      - ./modules/redisbloom.so:/data/redisbloom.so
    command: ["redis-server", "--loadmodule", "/data/redisbloom.so"]
    ports:
      - "6379:6379"
```

Here:

- `<span class="s1">./modules/redisbloom.so</span>` is the local path on your host machine.
- `<span class="s1">/data/redisbloom.so</span>` is the path inside the container.

Make sure the <span class="s2">.so</span> file exists in the specified directory before running Docker Compose.

#### **Restart the Redis Service**

After updating the Compose file, restart the service:

```
docker-compose down
docker-compose up -d
```

This will reload Redis with the specified module.

#### **Verify the Module is Loaded**

Once Redis is running, connect to it using redis-cli:

```
docker-compose exec redis redis-cli -a <yourPassword>
```

Run the following command:

```
MODULE LIST
```

Expected output:

```
1) 1) "name"
   2) "bf"
   3) "ver"
   4) (integer) 20207
```

This confirms the module (in this case, <span class="s1">bf</span> for RedisBloom) is loaded and active.

## **Checking Module Availability &amp; Compatibility**

Redis modules must match the Redis server version and platform. You can verify compatibility through the module’s documentation or by testing it in a local development setup before using it in production.

To inspect module-related details:

```
INFO MODULES
```

To verify the correct Redis image is being used:

```
docker-compose exec redis redis-server --version
```

If a module fails to load, check the container logs:

```
docker-compose logs redis
```

This often reveals missing paths or compatibility issues.

## **Updating or Unloading Modules**

Unlike MySQL, Redis does <span class="s2">**not**</span> support dynamic unloading of modules once loaded. To update or remove a module:

1. **Stop the container:**

```
docker-compose down
```

2. **Edit docker-compose.yml:**
    
    
    - Change the <span class="s1">.so</span> file path if updating the module.
    - Remove the `<span class="s1">--loadmodule</span>` line if unloading the module.
3. **Restart the container:**

```
docker-compose up -d
```

Always test updated modules in staging before applying to production.

## **Troubleshooting Common Module Issues**

<table border="1" id="bkmrk-issue-cause-resoluti" style="width: 100%; height: 262.766px; border-collapse: collapse; border-color: rgb(0, 0, 0);"><thead><tr style="height: 29.7969px;"><th style="width: 27.3902%; height: 29.7969px; border-color: rgb(0, 0, 0);">**Issue**

</th><th style="width: 27.9762%; height: 29.7969px; border-color: rgb(0, 0, 0);">**Cause**

</th><th style="width: 44.5145%; height: 29.7969px; border-color: rgb(0, 0, 0);">**Resolution**

</th></tr></thead><tbody><tr style="height: 46.5938px;"><td style="width: 27.3902%; height: 46.5938px; border-color: rgb(0, 0, 0);">Redis fails to start

</td><td style="width: 27.9762%; height: 46.5938px; border-color: rgb(0, 0, 0);">Incorrect module path or incompatible binary

</td><td style="width: 44.5145%; height: 46.5938px; border-color: rgb(0, 0, 0);">Check <span class="s1">docker-compose logs redis</span> and verify the <span class="s1">.so</span> path and architecture

</td></tr><tr style="height: 46.5938px;"><td style="width: 27.3902%; height: 46.5938px; border-color: rgb(0, 0, 0);">MODULE command not recognized

</td><td style="width: 27.9762%; height: 46.5938px; border-color: rgb(0, 0, 0);">Using a Redis image without module support

</td><td style="width: 44.5145%; height: 46.5938px; border-color: rgb(0, 0, 0);">Use an image like <span class="s1">redis/redis-stack-server</span> which supports modules

</td></tr><tr style="height: 46.5938px;"><td style="width: 27.3902%; height: 46.5938px; border-color: rgb(0, 0, 0);">“Can’t open .so file”

</td><td style="width: 27.9762%; height: 46.5938px; border-color: rgb(0, 0, 0);">Volume not mounted or permission denied

</td><td style="width: 44.5145%; height: 46.5938px; border-color: rgb(0, 0, 0);">Ensure the <span class="s1">.so</span> file exists locally and is readable by Docker

</td></tr><tr style="height: 46.5938px;"><td style="width: 27.3902%; height: 46.5938px; border-color: rgb(0, 0, 0);">Module not appearing in MODULE LIST

</td><td style="width: 27.9762%; height: 46.5938px; border-color: rgb(0, 0, 0);">Module failed to load silently

</td><td style="width: 44.5145%; height: 46.5938px; border-color: rgb(0, 0, 0);">Double-check command and container logs

</td></tr><tr style="height: 46.5938px;"><td style="width: 27.3902%; height: 46.5938px; border-color: rgb(0, 0, 0);">Commands from the module not recognized

</td><td style="width: 27.9762%; height: 46.5938px; border-color: rgb(0, 0, 0);">Module not loaded properly or incompatible

</td><td style="width: 44.5145%; height: 46.5938px; border-color: rgb(0, 0, 0);">Validate Redis version and module compatibility

</td></tr></tbody></table>

## **Security Considerations**

Redis modules execute native code with the same privileges as Redis itself. Only load trusted, vetted modules from official sources. Avoid uploading or executing arbitrary <span class="s2">.so</span> files from unknown authors. In multi-tenant or exposed environments, module misuse could lead to instability or security risks. Ensure the <span class="s2">redis</span> user inside the container has limited privileges, and module directories have appropriate permissions.