Trying to learn docker here but I am a bit confused on what the difference is between docker.io and docker. Is docker.io
the daemon server and docker
the client? Why does the daemon need to run all the time?
5 Answers
If you are using Ubuntu, and you do an
sudo apt-get install docker
You will get a package described as a "System tray for KDE3/GNOME2 applications"
If on the other hand, you do
sudo apt-get install docker.io
You will get a package described as "Docker complements kernel namespacing with a high level API which operates at the process level." i.e. the Docker everyone is usually thinking about when they say Docker.
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2
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2How does this answer the question, i.e. "what's the difference ...?"? Dec 1, 2017 at 14:42
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4this answered my question, because I was confused that
apt-get install docker
on ubuntu 18.04 didnt't gave me the docker application and I looked what the difference between those two is (apt-cache search ^docker
would have told me that, too) May 9, 2018 at 8:26 -
26The answer is that
docker
is a tray plugin, whiledocker.io
is the Docker containerization software. Ubuntu already had a package calleddocker
so they had to call the package for the Docker container softwaredocker.io
Nov 27, 2018 at 3:39 -
3This is the best answer as it actually tells you that if you want to install the container software, you should use
sudo apt-get install docker.io
– JacKeownMay 1, 2019 at 20:57
docker-io
is the deb package name used by Ubuntu distribution
docker-engine
is the deb package name from the official Docker Ubuntu distribution.
Probably you want docker-engine
because the Ubuntu one is too old and buggy to be used. As of today Ubuntu has 1.6.2 and Docker registry has 1.12.0 !
In terms of Docker, 1.6.2 counts as stone-age.
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4The difference seems to have narrowed now in Xenial: Ubuntu's docker.io 1.12.3 vs Docker's docker-engine 1.13.1.– PierzFeb 20, 2017 at 16:47
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@Pierz but will ubuntu upgrade within the same release? Before 18.04 the difference will probably widen again ;)– nafgMar 2, 2017 at 3:43
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4one year later, "mind the gap": the versions available via docker(.com) vs the ubuntu pkg repo is now so wide it's hard to even compare (as of mid-2017, ubuntu 17.04 (zesty)). What was called
docker-engine
from docker.com is now split intodocker-ce
anddocker-ee
(a free "community edition" & paid "enterprise edition", respectively), anddocker-compose
must be installed either from git or viapip install docker-compose
to get the correct, corresponding latest version. Presently, sadly, one must simply avoid ubuntu repos for all things docker.– michaelJul 30, 2017 at 23:30
Docker is the name of the open platform for developers and sysadmins to build, ship, and run distributed applications. Docker.io on the other hand is the name of the package that you install in your Linux OS (i.e. Ubuntu). See this link here.
In terms of how it works, the Docker Engine consists of two parts: a daemon, a server process that manages all the containers, and a client, which acts as a remote control for the daemon. I would suggest you to try a quick demo they have on their site, located here.
From a usability standpoint, you invoke the Docker client anytime you use the docker
command.
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5Yes, but that doesn't say anything about the two different processes, namely docker and docker.io– PithikosJul 18, 2014 at 15:30
It seems docker is just a symbolic link to docker.io:
> file $(which docker)
/usr/local/bin/docker: symbolic link to `/usr/bin/docker.io'
So we can assume that docker.io is both the daemon and the client process, just invoked with different flags I assume?!
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That's it exactly. docker.io uses the same binary for both client and server/daemon. Apr 17, 2016 at 15:22
Talking about Debian packages: docker.io
is the name of the package provided by Debian/Ubuntu, while docker
is the name of the package provided by docker.com.
Technically, these packages are built differently: for docker.io
the build dependencies are fetched from Debian packages, while for docker
, the build dependencies are in-tree, in the vendor
directory.
If you want more details, I wrote a detailed blog post at: https://www.collabora.com/news-and-blog/blog/2018/07/04/docker-io-debian-package-back-to-life/