[aspect-devel] Interest in providing and using software containers

[Louise Kellogg]

Thanks Timo, I have used VMs but am new to docker. We’ve had several suggestions to move tutorials to containers, so these specifics are helpful. 
> On Feb 6, 2017, at 10:42 AM, Timo Heister <heister at clemson.edu> wrote:
> 
>> Can you elaborate more on this?  My impression is that VMs work extremely well in tutorials by giving everyone a guaranteed working system, but it can be a bit of a barrier for people to transition to using the software for research on their own after the tutorial. My impression is that containers would help with this because the use environment can be the same during and after the tutorials. On the other hand, your comment suggests that VMs would be better at assuring success during the tutorial itself.
> 
> I don't see any advantage in docker for transitioning to using the
> software for research. Why do you think so?
> 
> A couple of things why I am hesitant to advertise docker:
> - The GUI experience is not great. While you can access the files
> inside, this is not without problems. Bundling X applications like
> paraview blows up the containers (to the point where they are as big
> as a vm). I don't have any experience running X applications with
> docker on windows but I would expect this to be a problem. This makes
> it impossible to use during tutorials and difficult afterwards. The
> only exception would be if everything is in jupyter notebooks.
> - Docker is ephemeral by default. This means any data is gone after
> you exit your container unless you do the extra effort to create data
> volumes or mount host directories. This is complicated (need to
> understand the differences between containers and images, etc.).
> - User accounts/isolation/permissions/mounting is still a problem. If
> you mount files inside your docker container, you have to be really
> careful about user ids. This is very difficult to understand
> especially for novices. Mounting a shared directory using virtualbox
> is much easier and also works on windows.
> - Security. Using docker requires root access on linux. I am not root
> on my workstation in my office so I am unable to use it (without
> jumping through hoops). Getting an admin to install virtualbox is easy
> (in fact it is installed by default here). Any docker container you
> run can take over your system. (Yes, I know you can run docker inside
> a vm, docker-machine is great).
> - VMs are much easier to understand. How do you explain things like
> starting/stopping/deleting containers, retaining files, etc.? Compare
> this with the default experience for
> http://www.math.clemson.edu/~heister/dealvm/ You download, double
> click, hit run and you are greeted with an open firefox windows inside
> the vm with information about the software and where to find help. You
> can stop and restart whenever you want and you keep all your files.
> 
> Don't get me wrong, I use docker a lot (daily), but I think it is only
> good for advanced users.
> 
> Best,
> Timo
> 
> 
> -- 
> Timo Heister
> http://www.math.clemson.edu/~heister/
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