Statistics on basic operating systems in images on the Docker Hub

The American company Anchore, created by the founder of Ansible Inc., analyzed its Docker Hub using the Anchore Navigator service for researching container images, and answered the following questions:

1. What operating systems are most used?
2. How did OS selection change over time?
3. Are the patterns of their use for official and public images?

Technical details

The basis for the mentioned service Anchore Navigator is a set of Python-utilities that are distributed under the free license (Apache License 2.0) on GitHub . Viewing the source helps to find out how technically information about images is collected. For example, defining a Linux distribution is trivially running lsb_release .
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It should also be clarified that, since in different repositories of images follow different release cycles, in this study, the authors took into account only the operating system from the last protected release. For some images ( library/swarm:latest given as an example), it was impossible to determine the OS, since "Such images are often statically collected binaries and do not require anything beyond this to run."

Finally, at the moment only Docker Hub images were analyzed, but in the future we plan to add statistics on the Amazon EC2 Container Registry (Amazon ECR).

Used OS

Official images

The clear favorite among distributions used as the base operating systems for official images is Debian , and Alpine and Ubuntu are far behind it:



How have the preferences for base distributions changed over the last year?



Of the more or less stable trends, one can only note the gradual growth of Alpine (due to a slight decrease in the popularity of Debian), but it is too early to predict anything based on these data.

Which versions of Debian are preferred? Everything is logical: with the release of 9 "Stretch" (in June), this release began to "take away" a share from the previous release - 8 "Jessie".

Public images

Official repositories are perhaps the most popular, but in quantitative terms this is only a small part of everything that can be found on the Docker Hub. Therefore, the images from the community (public) were also analyzed in Anchore, and the results were somewhat different.

The most popular distribution is ...



... yes, again Debian. However, the difference with Alpine is already minimal. But if we look at the time perspective, then the leadership was not eternal: at one time, Debian was inferior to both Ubuntu (December '16 — January'17), and Alpine (June '17).



In general, there is a similar tendency: lately, the popularity of Debian has slightly decreased, while in Alpine it has been growing. The third distribution, Ubuntu, reached its minimum in June, but went up again. Appearing in the Raspbian distributions rating indicates the community’s interest in Docker images on the respective devices.

Image size

The choice of the base operating system for containers for many is due to the size of the final image: really, why (all other things being equal) drag files into the image that will not be used in it exactly? Therefore, experts from Anchore included this criterion in their research.

It is unlikely that anyone will be surprised that the image of the base OS is minimal in BusyBox and Alpine. Of the “general purpose” distributions, Debian / Ubuntu and openSUSE occupy a middle position (about 110-120 MB), while Oracle Linux and Fedora (more than 200 MB) are the “thickest” ones.



What are the size of the final images based on different systems? It's pretty obvious: “on average in the hospital” the smallest images are based on BusyBox and Alpine, and the largest ones are from CentOS, Ubuntu and Debian. For obvious reasons, Raspbian shows an excellent indicator. At the same time, official images, as a rule, are on average much smaller than images from the community. But it is interesting that Alpine turned out to be the “black sheep” here, the images from the community based on which are on average less official.

PS

Finally, the statistics of a slightly different kind from last year - about the increase in the number of pull'ov in the Docker Hub against the background of the Docker development stages (to find a newer one, unfortunately, is not possible) :



We use Ubuntu as the base system for our images, and you?

PPS Read also in our blog:

• “ We assemble Docker images for CI / CD quickly and conveniently along with dapp (review and video) ”.
• “ What famous companies use Docker in production and for what?” "