CDE: Automatically creating portable

software packages

Philip J. Guo pg@cs.stanford.edu

Ph.D. student, Department of Computer Science Advisor: Prof. Dawson Engler

Project web page: http://www.stanford.edu/~pgbovine/cde.html

Problem: Software is hard to install Why  is  it  so  hard  to  get  so.ware  that  works  fine  on  your  computer  to  install  and  run  on  someone  else’s  computer?  

1.  You  might  not  remember  all  of  the  (o4en  implicit)  dependencies  

2.  Lots  of  dependencies,  each  with  their  own  obscure  dependencies  

3.  Libraries  conflict  with  versions  that  exisBng  programs  require  

4.  Libraries  might  not  be  compaBble  across  different  OS  variants  

5.  User  might  not  even  have  root  permission  to  install  so4ware  

Our solution: Don’t install anything

2.  Transfer  package  

A  package  is  simply  a  directory  of  files  (~10MB  –  500MB),  so  it  can  be  transferred  via  USB  sBck,  DVD,  or  over  the  Internet  

3.  Execute  so.ware  from  within  package  on  any  modern  Linux  computer  

Prepend  those  same  commands  with  ‘cde-­‐exec’,  and  CDE  runs  them  naBvely  without  any  installaBon  

1.  Create  package  on  your  Linux  computer  

Prepend  any  set  of  commands  with  ‘cde’,  and  CDE  runs  them  and  automaBcally  packages  up  their  dependencies  

Details: Creating a CDE package

Linux  kernel  

cde   monitored  process  ptrace  

open(“/lib/libc.so.6”)  chdir(“foo/”)  

Basic  idea:  cde  monitors  all  files  that  the  target  program  accesses  and  copies  them  into  a  self-­‐contained  package  

Details: Executing a CDE package

cde-­‐exec   monitored  process  ptrace  

open(“/lib/libc.so.6”)  chdir(“foo/”)  

Basic  idea:  cde-­‐exec  monitors  and  redirects  all  file-­‐related  system  calls  to  refer  only  to  files  within  the  package  

Linux  kernel  

Summary of results

2006   2011  2009  2007   2008   2010  

Our experiments show that 16 CDE packages from diverse sources can properly execute on six popular Linux distributions from the past 5 years with no installation or configuration

Package sizes range from 14MB to 476MB, depending on complexity

Run-time slowdowns acceptable, ranging from ~0% to 30% slower

Real-world use cases 1. Distributing self-contained portable software packages!

2. Allowing users to run live demos of prototypes!

(These anecdotes all come from real users throughout academia and industry)

CDE eliminates the need for users to obtain, compile, and install any dependencies before running your software!

Real-world use cases 3. Deploying computations to cluster or cloud computing!

4. Making scientific experiments reproducible!

No need to get root permission or install dependencies on cluster!

(These anecdotes all come from real users throughout academia and industry)

Colleagues can easily re-run and modify your experiments

on any Linux machine!

Real-world use cases

(These anecdotes all come from real users throughout academia and industry)

5. Running production software without perturbing existing OS!

6. Running production software in non-native environments!

Users might not want to take the risk of messing up a live production OS by installing

or upgrading libraries!Google Earth running with CDE on a 2006 Linux distro!

(impossible to run it natively on that distro)!