[[TOC]]
== Exploring OSG ==

 [http://www.opensciencegrid.org/ OSG] is a consortium of software, service and resource providers and researchers, from universities, national laboratories and computing centers across the U.S., who together build and operate the OSG project. The project is funded by the NSF and DOE, and provides staff for managing various aspects of the OSG. OSG is greatly involved with providing inter-operable systems for research communities in the areas of high energy physics (for eg., ATLAS, CMS programs of the LHC project) as also in biology, medicine, chemistry and education out-reach programs. 

 OSG has detailed [https://twiki.grid.iu.edu/bin/view/Documentation/WebHome documentation] on its operations, services, policies, faqs, and help.

 The foremost thing to achieve in ultimately making use of OSG resources is to obtain an account in one of the many [http://www.opensciencegrid.org/VO_List Virtual Organizations (VOs) affiliated to OSG].[[BR]] 

 Of interest to UAB are two VOs, [http://www.opensciencegrid.org OSG] and [http://osg-engage.renci.org/ Engage][[BR]] 
 [https://twiki.grid.iu.edu/twiki/bin/view/Engagement/WebHome Engage VO] is the result of the partnership of Renaissance Computing Institute (RENCI) and Clemson University. This VO is aimed more towards researchers other than the high energy physics domain and users new to OSG.[[BR]]
 [http://www.opensciencegrid.org/About/Join_the_OSG/Use_OSG_Resources OSG VO] is a general-purpose VO for individuals or small groups intending to use OSG for independent research.

== Engage VO ==

 [https://twiki.grid.iu.edu/bin/view/Engagement/EngageNewUserGuide Engage User Guide] details the following steps:
 1. First is to get a Personal certificate from DOEGrids. Two ways - through browser or command-line through cert scripts package.
  a. Browser 
   * [https://twiki.grid.iu.edu/bin/view/Engagement/EngageNewUserGuide#Updating_the_DOEGrids_CA_Chain First get a DOE Grid CA Chain], so that your browser recognizes and trusts this particular CA and does not prompt again in the future.
   * [https://twiki.grid.iu.edu/bin/view/Documentation/CertificateGet#Obtain_a_certificate_via_web_bro Obtain the Personal certificate]
   * Import the certificate into the browser
   * Export/Backup Certificate to local machine[[BR]] 
     '''NOTE:  For Mozilla Firefox - 3.0.5'''[[BR]]
     Go to Edit -> Preferences -> Advanced -> Encryption tab -> View Certificate -> Your Certificates tab -> Backup. Here will be the DOE Grid CA in '''.p12''' extension. Backup the cert onto your desktop and copy it to the machine you will be launching your jobs from
   * [http://www.doegrids.org/pages/cert-request.html Convert the key pair for use by Globus ''grid-proxy-init''] by the following two commands:
{{{
openssl pkcs12 -in my-cert.p12 -clcerts -nokeys -out $HOME/.globus/usercert.pem  
openssl pkcs12 -in my-cert.p12 -nocerts -out $HOME/.globus/userkey.pem 
chmod go-rw ~/.globus/userkey.pem 
chmod go-r ~/.globus/usercert.pem  
}}}
  b. Command-line, by [https://twiki.grid.iu.edu/bin/view/Documentation/CertificateGet#Install_cert_scripts_package installing the certificate scripts package]
 2. [https://twiki.grid.iu.edu/bin/view/Engagement/EngageNewUserGuide#3_Joining_the_Engage_VO Join Engage VO]. This registration is achieved in 2 phases.
   * Phase I - fill in your details, Name, Institution, email ID. As a result you will get an email and a link to phase II in the confirmation email. Follow the link and proceed to Phase II
   * Phase II - Read the Grid and VO AUP and accept
   * Now we become a member of the group Engage
 3. After becoming a member of Engage VO, to get an account on RENCI submit host, engage-submit.renci.org, send an email to engage-team@OPENSCIENCEGRID.ORG, requesting the same.
 4. Follow the link, you get in the return email, fill in the details and Accept. You will again get a confirmation email from RENCI with the user name you requested and would have to wait 2 hours before you can log into the submit host 

=== OSG Certificates, Security, and Policies ===

 The OSG generally accepts X509 certificates issued by Certification Authorities accredited by the IGTF from many different locations around the world. Most people working with OSG may obtain certificates from the DOEGrids CA and these instructions apply only to DOEGrids. Its worthwhile noting the DOE Certificate Policy and Certification Practice Statement (pdf attached). Of interest are section 1. Introduction, section 4.Operational Requirements and Appendix N. Open Science Grid (OSG) RA Operational Procedures. [[BR]] 

 Also to note is the assertion of user identity by OSG. OSG stipulates that '''''You'll also need to list a sponsor, an individual known to the RA who has met you in person and can vouch for your identity. Your VO can help you identify the appropriate sponsor. If you have trouble identifying a known sponsor then use your supervisor as your sponsor and be sure to mention the name of your home institution in the -reason message of the cert-request script (or "Comments" field of the web form)'''''.[[BR]]

 Further information on certificates and on how to get a personal/host certificate is explained in the following links:[[BR]]
 https://twiki.grid.iu.edu/bin/view/Documentation/CertificateWhatIs [[BR]]
 https://twiki.grid.iu.edu/bin/view/ReleaseDocumentation/UserCertificate [[BR]]
 https://twiki.grid.iu.edu/bin/view/Documentation/CertificateGet [[BR]]
 https://twiki.grid.iu.edu/bin/view/ReleaseDocumentation/GetGridCertificates#Certificate_scripts_package [[BR]]
 
 When the above requirements are fulfilled, we are ready to install the [https://twiki.grid.iu.edu/bin/view/ReleaseDocumentation/ClientInstallationGuide OSG Client software] and get started on our job submissions.[[BR]]

 OSG client software comes with Condor-G and Globus toolkit. So, the jobs can be submitted with either condor commands or globus commands to OSG resources.