DockerCon, the conference for operators and developers of next-generation distributed apps built with containers, just wrapped up this past week in Austin. This year’s show was held at the Austin Convention Center and was the largest DockerCon to date with more than 5,000 developers, architects, sysadmins, hackers, and partners. For beginners to the most techie, there were dozens of Docker tutorials, hands-on labs, and deep dive talks and rows of ecosystem innovators. As Docker turned four years old, it was clear its container technology is growing up and according to some analysts, it’s even at a turning point. Here were my top takeaways from the show:

If we learned anything this week, it’s that Docker underscored openness for containers with the announcement of two open-source collaboration communities. While Linux has long been at the core of the container movement, it is even more so now.

"A year ago we were faced with the challenge of going multiplatform," Solomon Hykes, founder of Docker, said during his DockerCon keynote. "Not every platform provides a Linux subsystem." Docker built a Linux subsystem, which is now the new LinuxKit.

The LinuxKit and Moby Project efforts are aimed at helping developers and organizations build their own container-optimized Linux distributions. The Moby Project, aka the “Lego Club” for containers, builds on top of LinuxKit and other efforts from Docker to help a developer rapidly build and deploy a container platform.

This step validates the approach of using enterprise cloud building blocks for underlying storage operations and value-added data management functions needed by operations to match developers SLAs with them.

What was once an afterthought, the container community is recognizing that persistent storage is vital for performance and protection. In the Annual Container Adoption Survey, 26 percent of respondents identified persistent storage as one of the top container challenges for the second year in a row. Industry pundits believed early on that within container environments storage would take the longest to mature, but this year several storage vendors that included StorageOS, Virtuozzo, and newly-funded Portworx made announcements that clearly show this technology is maturing.

And while storage is now getting the attention it deserves in the Docker community, many large enterprises are still in the early adoption phase trying to determine whether they should run containers inside VMs or bare metal, and their overall storage needs. Either way users should focus on persistent storage capabilities that work with both VMs and bare metal to ensure seamless portability and performance for the future.

One thing that was clear from the user case studies shared on stage is that enterprises want to keep persistent storage provided by storage players as Docker volumes.

Docker has always made security a priority as it built out its infrastructure and ecosystem, but native security features may not be enough to stop modern, complex threats. Because containers are ephemeral – lasting 2.5 days on average –  security visibility can be more difficult. Not to mention the sheer number of containers, requires IT departments to manage a larger security surface. In a recent Tenable Global Cybersecurity Assurance Report Card, only 52 percent of security professionals felt their organization had a handle on how to assess risks within container environments. Docker and its partner network clearly understand the seriousness of security threats. This year alone, 10 vendors, including Docker, made significant security announcements at DockerCon.

From open source collaboration to persistent storage and security, these are a few of the show highlights that resonated with me this week.