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Multi-user clusters are still quite common in HPC. And I think you're not going to see a switch away from multi-user systems anytime soon. Single user systems l

Multi-user clusters are still quite common in HPC. And I think you're not going to see a switch away from multi-user systems anytime soon. Single user systems like laptops might be a good use-case, but even the laptop I'm using now has different accounts for me and my wife (and it's a Mac). When you have one OS that is used on devices from phones, to laptops, to servers, to HPC clusters, you're going to have this friction. Could Linux operate in a single-user mode? Of course. But does that really make sense for the other use-cases?

airocker 2y ago
you could potentially create multiple containers in that machine which are single user and give to every user who needs access. CPU/Memory/GPU can be assigned in any way you want(shared/not shared). Now no user can mess up another user.
- SoftTalker 2y ago
  It's not "that machine" it's a cluster of dozens or hundreds of machines that is partitioned in various ways and runs batch jobs submitted via a queuing system (probably slurm).
- wongarsu 2y ago
  Isn't that just reinventing multiuser operating systems? Normal Linux already has the property that no user can mess up any other user (unless they are root or have sudo rights)
  - airocker 2y ago
    no it is not
- weebull 2y ago
  Not containers, but cgroups, and that is how HPC clusters work today. You still need multiple users though.
whimsicalism 2y ago
is it? most HPC (if GPU clusters count) are probably in industry and managed by containers
- birdiesanders 2y ago
  Containers rely on many privilege separation systems to do what they do, they are in fact a rather extreme case of multi-user systems, but they tend to present as “single” user environs to the container’s processes.
  - airocker 2y ago
    Good software hides complexity. User does not have to understand user group permissions suid etc etc
  - whimsicalism 2y ago
    > they are in fact a rather extreme case of multi-user systems Are they? My understanding was that by default, the `dockerd` (or whatever) is root and then all containers map to the same non-privileged user.
- bayindirh 2y ago
  HPC admin here. Yes. First, we use user level container systems like apptainer/singularity, and these containers run under the user itself. This is also same for non academic HPC systems. From schedulers to accounting, everything is done at user level, and we have many, many users. It won’t change anytime soon.
  - pankajkumar229 2y ago
    there is no reason for users to be maintained in the kernel.
    - bayindirh 2y ago
      Can you elaborate on that?

airocker 2y ago

you could potentially create multiple containers in that machine which are single user and give to every user who needs access. CPU/Memory/GPU can be assigned in any way you want(shared/not shared). Now no user can mess up another user.

SoftTalker 2y ago
It's not "that machine" it's a cluster of dozens or hundreds of machines that is partitioned in various ways and runs batch jobs submitted via a queuing system (probably slurm).
wongarsu 2y ago
Isn't that just reinventing multiuser operating systems? Normal Linux already has the property that no user can mess up any other user (unless they are root or have sudo rights)
- airocker 2y ago
  no it is not
weebull 2y ago
Not containers, but cgroups, and that is how HPC clusters work today. You still need multiple users though.

whimsicalism 2y ago

is it? most HPC (if GPU clusters count) are probably in industry and managed by containers

birdiesanders 2y ago
Containers rely on many privilege separation systems to do what they do, they are in fact a rather extreme case of multi-user systems, but they tend to present as “single” user environs to the container’s processes.
- airocker 2y ago
  Good software hides complexity. User does not have to understand user group permissions suid etc etc
- whimsicalism 2y ago
  > they are in fact a rather extreme case of multi-user systems Are they? My understanding was that by default, the `dockerd` (or whatever) is root and then all containers map to the same non-privileged user.
bayindirh 2y ago
HPC admin here. Yes. First, we use user level container systems like apptainer/singularity, and these containers run under the user itself. This is also same for non academic HPC systems. From schedulers to accounting, everything is done at user level, and we have many, many users. It won’t change anytime soon.
- pankajkumar229 2y ago
  there is no reason for users to be maintained in the kernel.
  - bayindirh 2y ago
    Can you elaborate on that?