Simple Management

Another detail distinguishes MinIO from other solutions like the Ceph Object Gateway: The tool has a graphical user interface (GUI) as a client for the stored files. The program, MinIO Browser (Figure 2) prompts for the usual S3 user credentials when called. The user's buckets then appear in the overview. Various operations can be initiated in the GUI, but it is not as versatile as the command-line (CLI) client. Most admins will probably give priority to the CLI version, especially because it, unlike the GUI, is suitable for scripting.

Figure 2: The MinIO Browser acts as a graphical interface for accessing content stored in MinIO. ©MinIO

Interfaces to Other Solutions

One central concern of the MinIO developers is apparently to keep their solution compatible with third-party services, which, in practice, is very helpful because it means you do not have to take care of central services yourself (e.g., user management). Instead, you could combine a MinIO installation with an external identity provider such as WSO2 or Keycloak.

This principle runs throughout the software. MinIO itself comes with a key management service (KMS), for instance, which takes care of managing cryptographic keys. This part of the software is part of the encryption mechanism that secures stored data and implements true encryption at rest. However, if you are already using an instance of HashiCorp Vault, you also can link MinIO to it through the configuration, which avoids uncontrolled growth of solutions for specific applications.

Monitoring is another example: MinIO offers a native interface for the Prometheus monitoring, alerting, and trending solution; the developers also provide corresponding queries for Grafana. MinIO can be combined with various orchestrators, different load balancers (e.g., Nginx and HAProxy), or frameworks such as Istio.

MinIO makes sure these connections also work in the opposite direction. Anyone who uses typical applications from the Big Data environment (e.g., Kafka, Hadoop, TensorFlow) can query data directly from MinIO and store data there. Moreover, MinIO provides a powerful backend storage solution for most manufacturers of backend systems. Because the developers have supported the S3 protocol for years, MinIO is sufficiently compatible. If you use MinIO, you can therefore look forward to a versatile S3 store that communicates well with other components.

Commercial License

The described range of functions makes it clear that MinIO means hard work. Although MinIO Inc. released MinIO under the terms of the AGPLv3, it also offers an alternative licensing option that differs in some key aspects from the terms of the AGPLv3; however, the vendor remains vague about the exact benefits of the commercial license.

Some companies, they say, did not want to deal with the detailed obligations that AGPLv3 imposes on licensees. As an example, the manufacturer cites companies on its compliance website that want to distribute MinIO as part of their own solution. One example of this would be providers of storage appliances who use MinIO as part of their firmware. If such a provider uses MinIO under the terms of the AGPLv3, they must pass on the source code of the MinIO version used, including any modifications, to the customers and grant them the same rights as those granted to the vendor itself by the AGPLv3. If the vendor instead enters into a commercial license agreement with MinIO, the obligation to hand over the source code is waived.