Docker Engine provides cluster management and orchestration features in Swarm mode. MinIO server can be easily deployed in distributed mode on Swarm to create a multi-tenant, highly-available and scalable object store.
As of [Docker Engine v1.13.0](https://blog.docker.com/2017/01/whats-new-in-docker-1-13/) (Docker Compose v3.0), Docker Swarm and Compose are [cross-compatible](https://docs.docker.com/compose/compose-file/#version-3). This allows a Compose file to be used as a template to deploy services on Swarm. We have used a Docker Compose file to create distributed MinIO setup.
* Docker engine v1.13.0 running on a cluster of [networked host machines](https://docs.docker.com/engine/swarm/swarm-tutorial/#/three-networked-host-machines).
You can now [add worker nodes](https://docs.docker.com/engine/swarm/swarm-tutorial/add-nodes/) to the swarm by running the above command. Find detailed steps to create the swarm on [Docker documentation site](https://docs.docker.com/engine/swarm/swarm-tutorial/create-swarm/).
The example MinIO stack uses 4 Docker volumes, which are created automatically by deploying the stack. We have to make sure that the services in the stack are always (re)started on the same node, where the service is deployed the first time.
Otherwise Docker will create a new volume upon restart of the service on another Docker node, which is not in sync with the other volumes and the stack will fail to start healthy.
Before deploying the stack, add labels to the Docker nodes where you want the minio services to run:
Download the [Docker Compose file](https://github.com/minio/minio/blob/master/docs/orchestration/docker-swarm/docker-compose-secrets.yaml?raw=true) on your Swarm master. Then execute the command
This deploys services described in the Compose file as Docker stack `minio_stack`. Look up the `docker stack` [command reference](https://docs.docker.com/engine/reference/commandline/stack/) for more info.
After the stack is successfully deployed, you should be able to access MinIO server via [MinIO Client](https://docs.min.io/docs/minio-client-complete-guide) `mc` or your browser at http://[Node_Public_IP_Address]:[Expose_Port_on_Host]
Swarm doesn't automatically remove host volumes created for services. This may lead to corruption when a new MinIO service is created in the swarm. So, we recommend removing all the volumes used by MinIO, manually. To do this, logon to each node in the swarm and run
The services are exposed, by default, on the internal overlay network by their services names (minio1, minio2, ...).
The docker-compose.yml file also exposes the MinIO services behind a single alias on the minio_distributed network.
Services in the Swarm which are attached to that network can interact with the host "minio-cluster" instead of individual services' hostnames. This provides a simple way to loosely load balance across all the MinIO services in the Swarm as well as simplifies configuration and management.
* By default the Docker Compose file uses the Docker image for latest MinIO server release. You can change the image tag to pull a specific [MinIO Docker image](https://hub.docker.com/r/minio/minio/).
* There are 4 minio distributed instances created by default. You can add more MinIO services (up to total 16) to your MinIO Swarm deployment. To add a service
* By default the services use `local` volume driver. Refer to [Docker documentation](https://docs.docker.com/compose/compose-file/#/volume-configuration-reference) to explore further options.
* MinIO services in the Docker compose file expose ports 9001 to 9004. This allows multiple services to run on a host. Explore other configuration options in [Docker documentation](https://docs.docker.com/compose/compose-file/#/ports).
* Docker Swarm uses ingress load balancing by default. You can configure [external load balancer based](https://docs.docker.com/engine/swarm/ingress/#/configure-an-external-load-balancer) on requirements.
