4 ms·

It doesn't have to be in-place, or even compressed; it just has to be automatic and OS-integrated. With something like squashfs (with or without compression) th

It doesn't have to be in-place, or even compressed; it just has to be automatic and OS-integrated. With something like squashfs (with or without compression) the kernel handles all the paging, mapping, and decompression (if any). Of course there are the classical benefits like resource usage being more efficient, but more importantly, less userspace code that needs to worry/care about filesystems and file layout etc.

zozbot123 8y ago
> It doesn't have to be in-place, or even compressed; it just has to be automatic and OS-integrated. With something like squashfs (with or without compression) the kernel handles all the paging, mapping, and decompression (if any). Sure, but I don't think you can do that within a self-contained binary, the kernel doesn't really support that. It would have to just be a loopback image, and lose the whole "self-contained binary" angle that makes this different from all sorts of other container tech.
- pritambaral 8y ago
  > Sure, but I don't think you can do that within a self-contained binary, the kernel doesn't really support that. An executable binary can set up a mount namespace, mount /proc/self/exe or argv[0] (with some offset) as a loopback device within the namespace, and then execute a process within the mount.
  - hedora 8y ago
    It would probably only be a few lines of portable shell code. Mounting at an offset is one line; runing the executable is a second. Not sure what you have to do to manually drop into a container. (Though, I think you need to be root to run those lines, and you could put setuid root binaries in the image...)
    - pritambaral 8y ago
      > Though, I think you need to be root to run those lines If you're thinking of mounts, Linux is getting there: https://lwn.net/Articles/697278/ https://lwn.net/Articles/697278/ and https://lwn.net/Articles/755498/ https://lwn.net/Articles/755498/ If you're thinking containerisation, it has been possible for a while, and new improvements are coming up: https://www.youtube.com/watch?v=-PZNF8XDNn8 https://www.youtube.com/watch?v=-PZNF8XDNn8 and https://events.linuxfoundation.org/wp-content/uploads/2017/12/2018-LSS-Europe-Edinburgh-Namespaces-and-Capabilities_Christian-Brauner.pdf https://events.linuxfoundation.org/wp-content/uploads/2017/1...

zozbot123 8y ago

> It doesn't have to be in-place, or even compressed; it just has to be automatic and OS-integrated. With something like squashfs (with or without compression) the kernel handles all the paging, mapping, and decompression (if any). Sure, but I don't think you can do that within a self-contained binary, the kernel doesn't really support that. It would have to just be a loopback image, and lose the whole "self-contained binary" angle that makes this different from all sorts of other container tech.

pritambaral 8y ago
> Sure, but I don't think you can do that within a self-contained binary, the kernel doesn't really support that. An executable binary can set up a mount namespace, mount /proc/self/exe or argv[0] (with some offset) as a loopback device within the namespace, and then execute a process within the mount.
- hedora 8y ago
  It would probably only be a few lines of portable shell code. Mounting at an offset is one line; runing the executable is a second. Not sure what you have to do to manually drop into a container. (Though, I think you need to be root to run those lines, and you could put setuid root binaries in the image...)
  - pritambaral 8y ago
    > Though, I think you need to be root to run those lines If you're thinking of mounts, Linux is getting there: https://lwn.net/Articles/697278/ https://lwn.net/Articles/697278/ and https://lwn.net/Articles/755498/ https://lwn.net/Articles/755498/ If you're thinking containerisation, it has been possible for a while, and new improvements are coming up: https://www.youtube.com/watch?v=-PZNF8XDNn8 https://www.youtube.com/watch?v=-PZNF8XDNn8 and https://events.linuxfoundation.org/wp-content/uploads/2017/12/2018-LSS-Europe-Edinburgh-Namespaces-and-Capabilities_Christian-Brauner.pdf https://events.linuxfoundation.org/wp-content/uploads/2017/1...