4 ms·

there are about 60 mentions of the word "container" on that page, including a full chart of questions "Compared to Docker in a VM", such as "Where are container

there are about 60 mentions of the word "container" on that page, including a full chart of questions "Compared to Docker in a VM", such as "Where are containers run"? But the real question that should be at the top of the file, or at least that table of questions, is "what is a container"? So: what is a container? (As opposed to a VM.)

dmpk2k 11y ago
Container is a chroot jail on steroids. VM is a QEMU process (also in a container).
- logicallee 11y ago
  how can you run a totally different architecture from just a chroot jail? It doesn't make sense. How are you "on the metal" if you're running some totally different kernel from what the chroot-jail-host is running? You can't both be running the kernel on the metal...
  - dmpk2k 11y ago
    I'm not clear on the question. The containers don't run a different kernel. They're just regular processes, in an fancy evolution of a chroot jail. If you want to run something like Windows or FreeBSD, then you break out QEMU.
  - bcantrill 11y ago
    It might help to see my presentation entitled "Docker and the future of containers in production"[1][2]; it covers the fundamental building blocks here, and should answer your questions. (If that presentation leaves you looking for more depth on the LX branded zone technology on SmartOS, see my Surge illumos day presentation from last fall.[3]) [1] https://www.joyent.com/developers/videos/docker-and-the-future-of-containers-in-production https://www.joyent.com/developers/videos/docker-and-the-futu... [2] http://www.slideshare.net/bcantrill/docker-and-the-future-of-containers-in-production http://www.slideshare.net/bcantrill/docker-and-the-future-of... [3] http://www.slideshare.net/bcantrill/illumos-lx http://www.slideshare.net/bcantrill/illumos-lx
  - spdustin 11y ago
    QEMU runs in the container, in this case. So you've got a whole "yo dawg, I heard you like VM's in your containers" thing going on. I guess it's briefly described as a multi-tenant container system that isolates tenants by grouping them into parent containers? Maybe?
  - bahamat 11y ago
    It's not a different architecture. SmartOS is x86 based, as are the Linux binaries. What lx-brand zones do is present an alternate system call table to the binaries executed inside the zone. Those "lx" calls are compatible with the Linux system call table and get mapped and/or translated to illumos kernel system calls. Binaries don't know the difference.
    - mrbill 11y ago
      So Triton is basically (simplifying) Solaris / SmartOS zones with the LX stuff installed?
      - bahamat 11y ago
        It's that, plus cloud orchestration (i.e., SmartDataCenter) which includes sdc-docker, providing the Docker API and image management.
stephengillie 11y ago
The term "Virtual Machine" has a variety of meanings, depending on who you talk to - Kernels are using LLVMs, Java runs inside a VM, and hypervisors create sandboxed full-OS VMs. The full-OS VM requires/provides its own binaries, frameworks, and DLLs; not having to depend on the Host to provide these. A Container is like a Hypervisor, but instead of hosting a full-OS VM, the Container holds a Docker, which is just the code and data. Containers are similar to Application Pools or SQL Instances, and there are "Container Databases" which are much more self-contained than the traditional database. Containers depend on the Container OS for binary files, frameworks, and DLLs. I like to look at it as a spectrum: Bare metal - Virtual Machine - Container At one end, you're both running the binaries and scheduling threads. In the middle you're running binaries but not scheduling threads. On the other end, you're depending on the Host to do both.

dmpk2k 11y ago

Container is a chroot jail on steroids. VM is a QEMU process (also in a container).

logicallee 11y ago
how can you run a totally different architecture from just a chroot jail? It doesn't make sense. How are you "on the metal" if you're running some totally different kernel from what the chroot-jail-host is running? You can't both be running the kernel on the metal...
- dmpk2k 11y ago
  I'm not clear on the question. The containers don't run a different kernel. They're just regular processes, in an fancy evolution of a chroot jail. If you want to run something like Windows or FreeBSD, then you break out QEMU.
- bcantrill 11y ago
  It might help to see my presentation entitled "Docker and the future of containers in production"[1][2]; it covers the fundamental building blocks here, and should answer your questions. (If that presentation leaves you looking for more depth on the LX branded zone technology on SmartOS, see my Surge illumos day presentation from last fall.[3]) [1] https://www.joyent.com/developers/videos/docker-and-the-future-of-containers-in-production https://www.joyent.com/developers/videos/docker-and-the-futu... [2] http://www.slideshare.net/bcantrill/docker-and-the-future-of-containers-in-production http://www.slideshare.net/bcantrill/docker-and-the-future-of... [3] http://www.slideshare.net/bcantrill/illumos-lx http://www.slideshare.net/bcantrill/illumos-lx
- spdustin 11y ago
  QEMU runs in the container, in this case. So you've got a whole "yo dawg, I heard you like VM's in your containers" thing going on. I guess it's briefly described as a multi-tenant container system that isolates tenants by grouping them into parent containers? Maybe?
- bahamat 11y ago
  It's not a different architecture. SmartOS is x86 based, as are the Linux binaries. What lx-brand zones do is present an alternate system call table to the binaries executed inside the zone. Those "lx" calls are compatible with the Linux system call table and get mapped and/or translated to illumos kernel system calls. Binaries don't know the difference.
  - mrbill 11y ago
    So Triton is basically (simplifying) Solaris / SmartOS zones with the LX stuff installed?
    - bahamat 11y ago
      It's that, plus cloud orchestration (i.e., SmartDataCenter) which includes sdc-docker, providing the Docker API and image management.

stephengillie 11y ago

The term "Virtual Machine" has a variety of meanings, depending on who you talk to - Kernels are using LLVMs, Java runs inside a VM, and hypervisors create sandboxed full-OS VMs. The full-OS VM requires/provides its own binaries, frameworks, and DLLs; not having to depend on the Host to provide these. A Container is like a Hypervisor, but instead of hosting a full-OS VM, the Container holds a Docker, which is just the code and data. Containers are similar to Application Pools or SQL Instances, and there are "Container Databases" which are much more self-contained than the traditional database. Containers depend on the Container OS for binary files, frameworks, and DLLs. I like to look at it as a spectrum: Bare metal - Virtual Machine - Container At one end, you're both running the binaries and scheduling threads. In the middle you're running binaries but not scheduling threads. On the other end, you're depending on the Host to do both.