> It will be a setup where one jvm instance on the host basically serves the role of "master" in terms of class data and shared object loading while each container instance uses its memory allotment only for running computations specific to the application in that container while sharing memory objects with other containers as much as possible.
Eclipse OpenJ9 does something like this.
> A seamless solution to this would basically make the jvm an out of the box poor man's polyglot PaaS platform.
Trying to recreate OS resource-allocation guarantees without the the OS has been a bit of a fool's errand, historically. The OS has privileged access to hardware -- it has a view of activity and an ability to enforce guarantees that processes lack.
Add to that the amount of time and effort that has gone into operating systems to cover allocation of so many different kinds of resource under so many different conditions. It is really expensive to re-engineer that capability.
I've seen a lot of attempts at trying to share ostensibly multiuser systems above the OS level and they have mostly been unhappy once there is heavy usage. Databases, queues, the JVM, everything eventually needs to be isolated from unrelated workloads at some point. Containers and VMs are much better at providing that capability.
Eclipse OpenJ9 does something like this.
> A seamless solution to this would basically make the jvm an out of the box poor man's polyglot PaaS platform.
Trying to recreate OS resource-allocation guarantees without the the OS has been a bit of a fool's errand, historically. The OS has privileged access to hardware -- it has a view of activity and an ability to enforce guarantees that processes lack.
Add to that the amount of time and effort that has gone into operating systems to cover allocation of so many different kinds of resource under so many different conditions. It is really expensive to re-engineer that capability.
I've seen a lot of attempts at trying to share ostensibly multiuser systems above the OS level and they have mostly been unhappy once there is heavy usage. Databases, queues, the JVM, everything eventually needs to be isolated from unrelated workloads at some point. Containers and VMs are much better at providing that capability.