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Increase server utilization by packing multiple non-hostile tenants on it, quickly create test environments, have a volatile env. You can have all of those with

by betaby 10y ago

Increase server utilization by packing multiple non-hostile tenants on it, quickly create test environments, have a volatile env. You can have all of those with VMs although at much higher CPU, RAM usage cost.

boris 10y ago
With one big limitation: they must all run the same os kernel (so you cannot run say a Windows or FreeBSD container on a Linux host). In fact, nobody guarantees that say Fedora will run on an Ubuntu-built kernel. Or even on a kernel from a different version of Fedora. So, IMO, anything other than running the exact same OS on host and in container is a hack.
- the8472 10y ago
  > In fact, nobody guarantees that say Fedora will run on an Ubuntu-built kernel. "nobody guarantees" just means that you can't externalize the work of trying it and seeing if it works. I don't think that's a huge loss, considering the space of all possible kernels, configuration switches, patches and distro packages is huge. It's like refusing to use a hammer because nobody can assure you that hammer A was thoroughly tested with nail type B.
  - boris 10y ago
    No, its like using a nailgun A with nails Y when it's only guaranteed to work with nails X. Or like using a chainsaw A with chain Y when it says you should use X. But hey, at least you are not trying to use nails on a chainsaw... ;-)
  - vor1968 10y ago
    No. It's like shooting yourself in the face because your friend survived it.
- lloeki 10y ago
  > nobody guarantees As long as the ABI is stable and you don't reach out to something that would have moved within /{proc,sys,whatevs}, you're good. [0] [0]: https://en.wikipedia.org/wiki/Linux_kernel_interfaces https://en.wikipedia.org/wiki/Linux_kernel_interfaces
AstralStorm 10y ago
Measure the "much higher" before deciding. Especially after you apply solutions to reduce the memory and disk cost. I'd say the "much higher" is nowadays a relic of the past.

by betaby 10y ago

boris 10y ago

With one big limitation: they must all run the same os kernel (so you cannot run say a Windows or FreeBSD container on a Linux host). In fact, nobody guarantees that say Fedora will run on an Ubuntu-built kernel. Or even on a kernel from a different version of Fedora. So, IMO, anything other than running the exact same OS on host and in container is a hack.

the8472 10y ago
> In fact, nobody guarantees that say Fedora will run on an Ubuntu-built kernel. "nobody guarantees" just means that you can't externalize the work of trying it and seeing if it works. I don't think that's a huge loss, considering the space of all possible kernels, configuration switches, patches and distro packages is huge. It's like refusing to use a hammer because nobody can assure you that hammer A was thoroughly tested with nail type B.
- boris 10y ago
  No, its like using a nailgun A with nails Y when it's only guaranteed to work with nails X. Or like using a chainsaw A with chain Y when it says you should use X. But hey, at least you are not trying to use nails on a chainsaw... ;-)
- vor1968 10y ago
  No. It's like shooting yourself in the face because your friend survived it.
lloeki 10y ago
> nobody guarantees As long as the ABI is stable and you don't reach out to something that would have moved within /{proc,sys,whatevs}, you're good. [0] [0]: https://en.wikipedia.org/wiki/Linux_kernel_interfaces https://en.wikipedia.org/wiki/Linux_kernel_interfaces

AstralStorm 10y ago

Measure the "much higher" before deciding. Especially after you apply solutions to reduce the memory and disk cost. I'd say the "much higher" is nowadays a relic of the past.