OpenSearch images use `centos:7` as the base image. If you run Docker locally, we recommend allowing Docker to use at least 4 GB of RAM in **Preferences** > **Resources**.
To deploy multiple nodes and simulate a more realistic deployment, create a [docker-compose.yml](https://docs.docker.com/compose/compose-file/) file appropriate for your environment and run:
```bash
docker-compose up
```
To stop the cluster, run:
```bash
docker-compose down
```
To stop the cluster and delete all data volumes, run:
```bash
docker-compose down -v
```
#### Sample Docker Compose file
This sample file starts two data nodes and a container for OpenSearch Dashboards.
If you override `opensearch_dashboards.yml` settings using environment variables, as seen above, use all uppercase letters and periods in place of underscores (e.g. for `opensearch.url`, specify `OPENSEARCH_URL`).
{: .note}
## Configure OpenSearch
You can pass a custom `opensearch.yml` file to the Docker container using the [`-v` flag](https://docs.docker.com/engine/reference/commandline/run/#mount-volume--v---read-only) for `docker run`:
You can use this same method to [pass your own certificates](../docker-security/) to the containers for use with the [Security](../../security/configuration/) plugin.
If you receive the `curl: (52) Empty reply from server` error, you are likely protecting your cluster with the security plugin and you need to provide credentials. Modify the following command to use your username and password:
To create an interactive Bash session in a container, run `docker ps` to find the container ID. Then run:
```bash
docker exec -it <container-id> /bin/bash
```
## Important settings
For production workloads, make sure the [Linux setting](https://www.kernel.org/doc/Documentation/sysctl/vm.txt) `vm.max_map_count` is set to at least 262144. On the OpenSearch Docker image, this setting is the default. To verify, start a Bash session in the container and run:
```bash
cat /proc/sys/vm/max_map_count
```
To increase this value, you have to modify the Docker image. For other install types, add this setting to the host machine's `/etc/sysctl.conf` file with the following line:
```
vm.max_map_count=262144
```
Then run `sudo sysctl -p` to reload.
The `docker-compose.yml` file above also contains several key settings: `bootstrap.memory_lock=true`, `ES_JAVA_OPTS=-Xms512m -Xmx512m`, `nofile 65536` and `port 9600`. Respectively, these settings disable memory swapping (along with `memlock`), set the size of the Java heap (we recommend half of system RAM), set a limit of 65536 open files for the OpenSearch user, and allow you to access Performance Analyzer on port 9600.
## Customize the Docker image
To run the image with a custom plugin, first create a [`Dockerfile`](https://docs.docker.com/engine/reference/builder/):
RUN /usr/share/opensearch/bin/opensearch-plugin install --batch <plugin-name-or-url>
```
Then run the following commands:
```bash
docker build --tag=opensearch-custom-plugin .
docker run -p 9200:9200 -p 9600:9600 -v /usr/share/opensearch/data opensearch-custom-plugin
```
You can also use a `Dockerfile` to pass your own certificates for use with the [Security](../../security/) plugin, similar to the `-v` argument in [Configure OpenSearch](#configure-opensearch):
