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Federation Quickstart Guide Slack

This document explains how to configure Minio with Bucket lookup from DNS style federation.

Get started

1. Prerequisites

Install Minio - Minio Quickstart Guide.

2. Run Minio in federated mode

Bucket lookup from DNS federation requires two dependencies

  • etcd (for config, bucket SRV records)
  • CoreDNS (for DNS management based on populated bucket SRV records, optional)



Environment variables


This is comma separated list of etcd servers that you want to use as the Minio federation back-end. This should be same across the federated deployment, i.e. all the Minio instances within a federated deployment should use same etcd back-end.


This is the top level domain name used for the federated setup. This domain name should ideally resolve to a load-balancer running in front of all the federated Minio instances. The domain name is used to create sub domain entries to etcd. For example, if the domain is set to, the buckets bucket1, bucket2 will be accessible as and


This is comma separated list of IP addresses to which buckets created on this Minio instance will resolve to. For example, a bucket bucket1 created on current Minio instance will be accessible as, and the DNS entry for will point to IP address set in MINIO_PUBLIC_IPS.


  • This field is mandatory for standalone and erasure code Minio server deployments, to enable federated mode.
  • This field is optional for distributed deployments. If you don't set this field in a federated setup, we use the IP addresses of hosts passed to the Minio server startup and use them for DNS entries.

Run Multiple Clusters


export MINIO_ETCD_ENDPOINTS="http://remote-etcd1:2379,http://remote-etcd2:4001"
minio server http://rack{1...4}.host{1...4}{1...32}


export MINIO_ETCD_ENDPOINTS="http://remote-etcd1:2379,http://remote-etcd2:4001"
minio server http://rack{5...8}.host{5...8}{1...32}

In this configuration you can see MINIO_ETCD_ENDPOINTS points to the etcd backend which manages Minio's config.json and bucket DNS SRV records. MINIO_DOMAIN indicates the domain suffix for the bucket which will be used to resolve bucket through DNS. For example if you have a bucket such as mybucket, the client can use now to directly resolve itself to the right cluster. MINIO_PUBLIC_IPS points to the public IP address where each cluster might be accessible, this is unique for each cluster.

NOTE: mybucket only exists on one cluster either cluster1 or cluster2 this is random and is decided by how gets resolved, if there is a round-robin DNS on then it is randomized which cluster might provision the bucket.

3. Upgrading to etcdv3 API

Users running Minio federation from release RELEASE.2018-06-09T03-43-35Z to RELEASE.2018-07-10T01-42-11Z, should migrate the existing bucket data on etcd server to etcdv3 API, and update CoreDNS version to 1.2.0 before updating their Minio server to the latest version.

Here is some background on why this is needed - Minio server release RELEASE.2018-06-09T03-43-35Z to RELEASE.2018-07-10T01-42-11Z used etcdv2 API to store bucket data to etcd server. This was due to etcdv3 support not available for CoreDNS server. So, even if Minio used etcdv3 API to store bucket data, CoreDNS wouldn't be able to read and serve it as DNS records.

Now that CoreDNS supports etcdv3, Minio server uses etcdv3 API to store bucket data to etcd server. As etcdv2 and etcdv3 APIs are not compatible, data stored using etcdv2 API is not visible to the etcdv3 API. So, bucket data stored by previous Minio version will not be visible to current Minio version, until a migration is done.

CoreOS team has documented the steps required to migrate existing data from etcdv2 to etcdv3 in this blog post. Please refer the post and migrate etcd data to etcdv3 API.

4. Test your setup

To test this setup, access the Minio server via browser or mc. You’ll see the uploaded files are accessible from the all the Minio endpoints.

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