The open-source Docker container technology is popular for a number of reasons, particularly ease of virtualized application development and deployment.
A key tool in the Docker arsenal for development and deployment is Docker Hub—which was launched in June 2014 by Docker Inc., the lead commercial sponsor behind Docker—and has grown significantly over the course of the past year.
The Docker Hub is a central repository for "Dockerized" applications that can be deployed on a Docker host and, at launch, already had 14,000 applications. Docker Hub also is a platform that can enable developer workflow as part of a DevOp continuous integration and deployment approach. Docker Hub has grown in the last year, and Docker Inc. now claims that there are more 300,000 users of Docker Hub.
Docker Hub has both free and paid services. Paying users can create and manage private repositories.
"There is a healthy mix of paid and unpaid users," Scott Johnston, senior vice president of product at Docker Inc., told eWEEK. "We are not disclosing exact numbers at this time, but both are growing, with paid users growing at a faster rate than users consuming the service for free."
Looking at the size and scope of the infrastructure that is needed to support Docker Hub, Docker Inc. said that since the launch, they have used more than 200TB of storage and more than 400TB of network bandwidth. The majority of Docker Hub infrastructure is now hosted with a leading cloud service provider, Johnston said, but he did not specify the name of the provider. It's also not clear what the underlying network connectivity is that enables Docker Hub and whether it is a 10 Gigabit Ethernet or larger bandwidth pipe.
"Since we take advantage of our cloud service provider's network bandwidth as well as CDN [content delivery network], we don't know exactly the width of pipe as it is dynamic based on demand," Johnston said.
Another element of Docker Hub that has evolved over the past year is the core software that powers the repository, known as Docker Registry. Docker Registry 2.0 debuted in April. Among the big changes in Docker Registry 2.0 is the fact that it is built in Google's Go programming language while the previous iterations of Registry were built in the Python programming language.
Docker Hub is now based on Docker Registry 2, but still supports the v1 protocol so as to support older versions of the Docker Engines, Johnston said.
Security in Docker Hub also has improved over the past year in a number of different respects.
"The v2 Registry's image manifest enables verification of content integrity and transport security," Johnston said. "In addition, Docker Hub provides a Docker Notary server endpoint that supports Docker Content Trust to digitally sign images and verify image signatures."
Docker Content Trust is a capability that debuted in the Docker Engine 1.8 release on Aug. 12. The Docker Content Trust initiative includes the Docker Notary project that makes use of The Update Framework (TUF) standard to verify the integrity and authenticity of a given download.
Although the Docker Hub is a cloud based service, Docker Inc. also has an on-premises edition, originally named Docker Hub Enterprise, but now called Docker Trusted Registry.
"We had more than 800 participants in our private beta, and the pick-up since then has exceeded our expectations," Johnston said. "We've already publicly discussed one major customer—the GSA—and expect to discuss others in the upcoming months."
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.