Resource Containers: A new facility for resource management in server systems. Outline

Transcription

1 Resource Containers: A new facility for resource management in server systems By: Banga, Druschel and Mogul From: OSDI 99 presented by Peter Graham 2/21/2007 Resource Containers by Banga, Druschel and Mogul 1 Introduction The Problem Typical Server Models The Proposed Solution Outline Resource Containers Operations A Server with Resource Containers Resource Containers Implementation and Performance Conclusions 2/21/2007 Resource Containers by Banga, Druschel and Mogul 2 1

2 Introduction The paper is concerned with server systems File servers, web servers, compute servers, etc. We want to be able to accurately track and control access to OS resources by clients To enable fair sharing of, and charging for, resource consumption Challenge: current OS abstractions are inadequate to do this Clients/users are not always well identified at the servers so who should be charged, etc.? 2/21/2007 Resource Containers by Banga, Druschel and Mogul 3 The Problem Existing OS resource management mechanisms are most commonly tied to processes running on a given machine Processes (protection domains) are the unit of resource management the resource principal This is inadequate to permit servers to effectively manage their services Commonly, a single server process performs functions on behalf of different entities (i.e. clients) which are attributed to the single process 2/21/2007 Resource Containers by Banga, Druschel and Mogul 4 2

3 Typical Server Models Processes User level Kernel User level Kernel Pending Process per-connection Server (has high overhead!) Pending Single Process Multithreaded Server (who is charged? 1 process) 2/21/2007 Resource Containers by Banga, Druschel and Mogul 5 The Proposed Solution How can this problem be fixed? Must separate the notion of resource principal from that of process or any other type of protection domain Resource Containers are a new OS abstraction that does exactly this OS manages resource containers and tracks usage for them but they are not associated with any particular protection domain 2/21/2007 Resource Containers by Banga, Druschel and Mogul 6 3

4 The Proposed Solution Since resource containers are separate from processes, they may be associated with arbitrary computations Like network connections to a server With resource containers, the multithreaded server can be used (for efficiency) and client resource use can be managed via their connections (one container per client) 2/21/2007 Resource Containers by Banga, Druschel and Mogul 7 Resource Containers Operations Create a Container: processes create containers as needed and may manage several at once. (fork new container) Set Container s Parent: containers may be nested (e.g resources assigned to 1 container shared by its children) Sharing Containers: containers may be passed and shared between processes at will Hence, an application may be executed in >1 protection domain Container Release: containers are reclaimed once no one is using them Container Attributes: processes can exert control over containers (control resources in them) by setting attributes Container Usage Information: processes can collect usage information from containers (e.g. for charging purposes) 2/21/2007 Resource Containers by Banga, Druschel and Mogul 8 4

5 A Server with Resource Containers Process/Protection Domain Resource Containers Pending User level Kernel Single Process Multithreaded Server with Resource Containers (efficient and can manage/charge individually for each client) 2/21/2007 Resource Containers by Banga, Druschel and Mogul 9 Resource Containers Implementation & Performance Modifications to the Digital Unix 4.0D kernel 820 lines new code, changes to 6500 lines of existing code Operations on resource containers are low cost Operation Create container Destroy container Change thread s resource binding Obtain container resource usage Set/get container attributes Move container between processes Obtain handle for existing container Cost (μsec) Consider the following graph: LRP (Lazy Receiver Processing) refers to an earlier system 2/21/2007 Resource Containers by Banga, Druschel and Mogul

6 Resource Containers Implementation & Performance RC System 1 has server restricted to using 30% of CPU while RC System2 has server restricted to using 10%. 2/21/2007 Resource Containers by Banga, Druschel and Mogul 11 Conclusions Resource containers provide an effective mechanism for addressing the problem Separation of resource management from protection domain makes sense Resource containers may be efficiently implemented Resource containers also provide side benefits E.g. protections against SYN-flooding 2/21/2007 Resource Containers by Banga, Druschel and Mogul 12 6