from sandbox to playground: virtual environments and quality of service in the grids kate keahey...
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From Sandbox to Playground:
Virtual Environments and Quality of Service in the
Grids
Kate Keaheykeahey@mcs.anl.gov
Argonne National Laboratory
IEEE Fox Valley Subsection Kate Keahey
What are Grids?
Power Grid analogy: remote computing power can be accessible from your laptop in much the same way as electricity is delivered to your home
IEEE Fox Valley Subsection Kate Keahey
How do Grids work today? From Grid Services…
Discover remote resources Start jobs on remote resources Authenticate and authorize users and other entities Transfer data Globus Toolkit: a de facto standard in Grid
technologies … to commodity Grid usage
Combining and automating the use of basic Grid services
Utility computing paradigm Provide reliable, adaptive, QoS-based execution of
specific tasks
IEEE Fox Valley Subsection Kate Keahey
Grid Capabilities TodayAccess Grid: enable people, presentation software and programs to interact
Data Grid: combine distributed dataand access storage within one similation
Computational Grid: use access to powerful resources to run a genome analysis service
Experiment Grid: combine multiple technologies in support of an experiment
IEEE Fox Valley Subsection Kate Keahey
First, a little bit of theory… “Resource sharing & coordinated problem
solving in dynamic, multi-institutional virtual organizations”
Single sign-on creates a decentralized Grid domain within which Grid entities can act on behalf of the user
IEEE Fox Valley Subsection Kate Keahey
…now practice
Grid clients• create environments
More resources per user, more users per resource, more environments per resource….How do we scale?
Application developers• obtain the right configuration
Grid administrators• resolve conflicts!
IEEE Fox Valley Subsection Kate Keahey
What do we need? Quality of Service
Sandbox a Grid computation Reliable enforcement of policy-driven resource usage Applications in experimental sciences, fair resource
sharing, etc. Quality of Life
Dynamic capabilities Dynamically creating and managing remote execution
environments Dynamically configuring such environments Easily moving in a Grid as resources come and go
Automated, hands-off Grid infrastructure
IEEE Fox Valley Subsection Kate Keahey
How do we satisfy those needs?
Dynamic behavior: missing services Creating and managing remote execution
environments dynamically Customizing such environments
Ontologies and protocols Standardized descriptions can be processed
dynamically by various Grid entities Policy-adapting protocols will equip the system with
ability to respond to needs automatically Tools to obtain descriptions of these things easily
and automatically
IEEE Fox Valley Subsection Kate Keahey
Virtual Workspaces
Virtual resource configuration
Protection and enforcement environment
Software and file configuration state
Execution state
Virt
ual W
orks
pace
Grid
Mid
dle
wa
re
Inte
rfa
ceG
rid c
lien
t In
terf
ace
Grid clients
Grid middlewareinterface
VWs are represented by an ontology description Potentially integrating community policy
They can be implemented using different technologies They can be customized to the user needs and deployed in the
Grid
IEEE Fox Valley Subsection Kate Keahey
Properties of Virtual Workspaces Dynamic creation
Inherent property of Grid computation Avoiding a maintenance nightmare (automate administration) and
potential security hazard Dynamic configuration
To reflect changing policies in the Grid (implement agreements) Strong protection environment
Otherwise users won’t trust sites and sites won’t trust users Fine-grain enforcement Configurable architecture, software, environment
Application software/libraries/licenses Configurable environment Running 32-bit programs on 64-bit architectures Running a required version of the OS (Fedora vs. RH9) Potentially even execution state
IEEE Fox Valley Subsection Kate Keahey
VWs in the Grids
Clie
nt
request
VW EPR
inspect and manage
deploy & suspend
use existing VW Create VW
VW Factory
VW Repository
VW Manager
create new VW
ResourceVW
start program
IEEE Fox Valley Subsection Kate Keahey
VW Services Factory
Creates VW in terms of the implementation e.g., VM image, pacman chache+
May create based on an already created VW Writes/configures access policy May allow negotiation
VW Repository Access to state describing a VW Allows inspection, management, implementation-specific
termination, potentially renegotiation, etc. Soft-state lifetime management ensures termination
VW Manager Lightweight infrastructure deploying VMs
IEEE Fox Valley Subsection Kate Keahey
How can I obtain VWs? Through automatic negotiation and establishing
agreements with the community What is an agreement?
Relationship between parties dynamically-established and dynamically-managed
Terms Functional, e.g., a service I can perform Non-functional, e.g., performance, availability, etc.
Noteworthy Agreement Properties Simple, decentralized way of expressing aggregate or
proprietary policies in the system Allow providers to gauge demand Ephemeral, periodic, fine-grained, modifiable policy
WS-Agreement, GRAAP-WG, Global Grid Forum Currently under public comment: see www.gridforum.org
IEEE Fox Valley Subsection Kate Keahey
Implementing and Configuring Virtual Workspaces
Potential Implementation Groups Unix accounts and Unix account tools
setrlimit, DSRT, chroot, chown, and others Sandboxes
VServer, protection and fine-grain enforcement Virtual Machines
VMware, Xen, and others
Deployment & configuration tools Pacman & pacman cache
See also: Grid 2004: “From Sandbox to Playground:
Dynamic Virtual Environments in the Grid”
IEEE Fox Valley Subsection Kate Keahey
Comparing VW Implementations Unix accounts
Pros: efficient, ubiquitous Cons: very limited functionality Needs to be used in conjunction with other technologies
Pacman, additional system enforcement tools
Prototype available (GT 3.2) http://www-unix.mcs.anl.gov/~keahey/DS/DynamicSessions.htm
Currently on the way to become a GT4 service Sandboxes
Pros: efficient, fine-grain enforcement, typically very lightweight
Cons: limited state enforcement Need to be used in conjunction with other technologies
IEEE Fox Valley Subsection Kate Keahey
Comparing VW Technologies (cntd)
Virtual Machines Pros:
Flexibility (run linux on linux, 32 on 64-bit, etc.) Enhanced security, audit forensics, etc. Great user state management Freezing/migration Customized environment A promising distribution/deployment tool
Cons: Potential for being less efficient (emulation) Potential for resource overhead Poor implementation of sharing, relatively little enforcement (but can
be combined with other technologies for enforcement) Maturity issues
The potential is excellent, but needs more work
IEEE Fox Valley Subsection Kate Keahey
The Need for Speed
0
0.2
0.4
0.6
0.8
1
1.2
110100jt 110105jt 110109jt
UNIX acctVserverVMware
Comparison using the Fusion EFIT application
IEEE Fox Valley Subsection Kate Keahey
Other efficiency concerns
Startup time
Resource usage overhead Memory use: VMware: 24MB + 1 MB per 32 MB
memory allocated Disk use: VMware large
Table 1: DVE create/destroy times
Linux VServer VMware
Create 100 ms 360 ms 14-52 sec
Destroy 70 ms 200 ms 3-38 sec
IEEE Fox Valley Subsection Kate Keahey
Enforcement Capabilities
Unix account VServer VMware
CPU usage (sec) Via setrlimit() Not at present, but could be added
Not enforced
CPU usage (%) Not enforced Limited: no VServer can starve another
Not in VMware Workstation
Disk space usage Dynamically(per-user
quotas)
Dynamically (per context quotas)
Statically (virtual disks)
Memory usage No Not at present, but could be added
Statically
Network usage No Dynamically Dynamically
IEEE Fox Valley Subsection Kate Keahey
Virtual is the New Real! Virtual machines are a very interesting option for
the Grid Excellent usability potential:
Configurability, enhanced security, state management, replication, enforcement…
Even potential as distribution tool!
Excellent potential for optimizations Performance, resource usage, access to specialized
hardware, etc. are not so bad, especially with new technologies like Xen
Some maturity issues Do benefits outweigh challenges?
IEEE Fox Valley Subsection Kate Keahey
How does it work in practice? Recent project: combining VMs and Grids to create a
platform for bioinformatics applications Some of the conclusions:
Use of virtual machines can significantly broaden the resource base
Saves installation time EMBOSS installation: ~45 minutes Deploying a 2GB VM image: ~6.5 minutes Peace of mind: priceless!
Enforcement capabilities Depend on the implementation but are generally better than what we
have now
SC04 poster: “Quality of Life in the Grids: VMs meet Bioinformatics
Applications”, T. Freeman and D. Galron
IEEE Fox Valley Subsection Kate Keahey
How can VWs change the Grid? Challenges to the established Grid model
Security challenges Networking challenges And many, many others…
Issue of responsibility Who vets a workspace? Who is responsible for its “good behavior”?
The role of VOs is going to grow VO might take on additional responsibilities
Administers and maintains VMs, certification authority, could potentially stop suspect VMs, is to blame if something happens…
Should the VO be a legal entity? Do VOs have the resources to do that?
Are VOs going to become too heavyweight? What are the trade-offs and a healthy balance?
IEEE Fox Valley Subsection Kate Keahey
Virtual Playgrounds Define a virtual Grid in terms of requirements
Virtual workspaces Potentially networking requirements Other services
Provide mechanisms to create a Grid Provide services for the deployment of such “virtual playgrounds”
on real resources Ephemeric Grids built for a special purpose:
Family is getting together to decide when to spend Xmas Scientists getting up a Grid for the purposes of a specific
experiment run A game tournament A scientific simulation that gets discarded or interrrupted but can
potentially be restored later Towards a true utility computing model
IEEE Fox Valley Subsection Kate Keahey
Conclusions Addressing QoS and QoL is critical for the utility
computing model of Grids Unglamorous but necessary tasks Combating complexity, improving scalability Without it flexibly moving between resources on the
Grid is very hard Current technological advances make this model
ever closer to reality A breakthrough is required in terms of usability Virtual machines fit the bill
Virtual is the new Real! To find out more: www.mcs.anl.gov/~keahey
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