Virtual Private Grid VPG :

1
Virtual Private Grid (VPG) A Command Shell for
Utilizing Remote Machines Efficiently

• Kenji Kaneda, Kenjiro Taura, Akinori Yonezawa
  Department of Computer Science, University of
  Tokyo

Background
Virtual Private Grid Goals

• Improvement of network technology
• Connection of clusters and super computers with
  high-speed network
• Many people has accounts on a large number of
  machines
• Across multiple subnets and geographically
  distributed places

• Utilize remote machines through a shell at the
  local host
• Design and implement Virtual Private Grid
• Working around the restrictions automatically
• Utilizing a large number of machines in multiple
  subnets securely and efficiently

Local shell
Remote
cat_at_hostA File lpr_at_hostB
Remote
Problem
Functions of VPG

• These machines are managed by different
  administrators
• Various restrictions are imposed
• Firewall (IP filtering)
• DHCP
• Private IP, etc.
• Working around these restrictions requires human
  intervention
• It is difficult to utilize all the remote
  machines efficiently

• Nicknaming ( each host has a unique nickname)
• Job submission to any nicknamed host
• Redirection from/to a file at any nicknamed host
• Network pipe between any nicknamed host

• do not change administrative policy
• can combining existent programs with standard
  input/output through the network

Example Difficulty of Job Submission Across
Firewall
Syntax of the Shell

• Job submission
• Redirection
• Pipe

Private IP

• Restrictions
• Bypass of firewall
• Submission of jobs to nameless hosts
• A Possible Solution
• Keeping connections permanently between all the
  hosts
• Problem
• A large number of connections
• User involvement to minimize connections

ltPathgt_at_ltNicknamegt
ltPathgt_at_ltNicknamegt gt ltFilegt_at_ltNicknamegt ltPathgt_at_ltNick
namegt lt ltFilegt_at_ltNicknamegt
ltPathgt_at_ltNicknamegt ltPathgt_at_ltNicknamegt

• Selection of hosts which have no DNS name with
  nickname
• Automatic detection of the route to hosts

It is cumbersome to implement remote job
submission across multiple subnets
2
Overview of Implementation
Related Work

• Daemons boot up at hosts
• Each daemon creates and keeps necessary
  connections with SSH port forwarding
• DHCP clients create a connection to the outside
• Multiple subnets are connected
• Finally, daemons finish creating connections
• Network becomes connected
• Using self stabilizing spanning tree algorithm

• GlobusI.Foster et al. http//www.globus.org
• Providing basic services for global computing
• RMFY.Tanaka et al. IWCC99
• Utilizing resources inside the firewall
• UfoAlbert D. Alexandrov et al. USENIX87
• Providing global file system
• Secure Shell
• Providing secure access to remote machines
• Virtual Private Network
• Constructing a private network on the Internet

Subnet Y
Host D (Private IP)
Host C (DHCP client)
Difference between VPG and SSH
Subnet Z

• Methods to utilize a large number of machines
  with SSH
• Giving a shell window to each host
• It requires a large number of windows
• Creating connections whenever submitting a job
• It entails high overhead
• Using SSH port forwarding
• It requires an user involvement
• Advantages of VPG
• Minimum connections for all the hosts to
  communicate with each other
• Easy and efficient network pipe and redirection
• Job submission to nameless hosts

Host B
Host A (Home host)
Subnet X
the host which the user initially logins
Difference between VPG and VPN

• VPG constructs a private network at the user
  level
• VPG places major emphasis on remote job submission

Summary and Future Work
Live Connection Dead Connection

• Developing Virtual Private Grid
• Working around the restrictions automatically
• Utilizing remote machines securely and
  efficiently
• Easier and more efficient utilization of remote
  machines
• Automatic and parallel resource selection
• Simple scheduler
• Control of dependency relation of files
• Automatic generation of executables
• File sharing/sync, etc.

Subnet Y
Host D (Private IP)
Host C (DHCP client)
Subnet Z
Host B
Host A (Home host)
Subnet X