LIGOProvisioningUseCase

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LIGO provisioning Use Case

Institution: LIGO

Author: Scott Koranda

Brief Description of the LIGO VO

LIGO, the Laser Interferometer Gravitational-wave Observatory seeks to detect gravitational waves--ripples in the fabric of spacetime. The LIGO Scientific Collaboration (LSC), a self-governing collaboration, was founded in 1997
and currently has more than 800 members from 70 institutions worldwide. LIGO is the funded by the NSF.

Sketch of LIGO provisioning

Consider the case of a new data analyst, named Scott Koranda, joining the collaboration by joining the LSC group at the University of Wisconsin-Milwaukee. The following types of resources must be provisioned:

• the Kerberos principal scott.koranda@LIGO.ORG is created in the master KDC and replicated to the slave KDCs
• in the LIGO master LDAP server the following dn is created:

  dn: employeeNumber=882,ou=people,dc=ligo,dc=org
  cn: Scott Koranda
  objectClass: top
  objectClass: person
  objectClass: organizationalPerson
  objectClass: inetOrgPerson
  objectClass: eduPerson
  objectClass: posixAccount
  objectClass: krbPrincipalAux
  objectClass: eduMember
  objectClass: x-LIGO-TWikiObject
  objectClass: qmailUser
  uidNumber: 40882
  street: UWM Physics Department$P.O. Box 413
  uid: scott.koranda
  employeeType: Faculty, Sr. Sci/Eng
  facsimileTelephoneNumber: +1 414 229 5589
  x-LIGO-TWikiLoginName: scottkoranda
  postalCode: 53201
  postalAddress: UWM Physics Department$P.O. Box 413$Milwaukee$WI$53201$US
  telephoneNumber: +1 414 229 5056
  description: /DC=org/DC=LIGO/OU=People/CN=Scott Koranda
  gidNumber: 40882
  employeeNumber: 882
  krbPrincipalName: scott.koranda@LIGO.ORG
  x-LIGO-TWikiName: ScottKoranda
  l: Milwaukee
  st: WI
  eduPersonAffiliation: University of Wisconsin at Milwaukee
  sn: Koranda
  homeDirectory: /home/scott.koranda
  givenName: Scott
  mail: scott.koranda@ligo.org
  mailAlternateAddress: skoranda@gmail.com
  mailForwardingAddress: skoranda@gravity.phys.uwm.edu
  

• Additionally the following dn is created:

  dn: cn=scott.koranda,ou=group,dc=ligo,dc=org
  objectClass: top
  objectClass: posixGroup
  gidNumber: 40882
  cn: scott.koranda
  

• the subject (in Grouper terms) scott.koranda@LIGO.ORG is added in Grouper to the Group Communities:LVC:LSC:MOU:UWM:UWMGroupMembers and because of that becomes a member of a number of composite groups. These are provisioned into LDAP so that the dn above also has attributes

isMemberOf: Communities:LVC:LVCGroupMembers
isMemberOf: Communities:LVC:LSC:MOU:UWM:UWMGroupMembers
isMemberOf: Communities:LVC:LSC:LSCGroupMembers
isMemberOf: Communities:LSCVirgoLIGOGroupMembers

• since scott.koranda@LIGO.ORG is in the LDAP then that Kerberos principal can be used to login to various SSH servers that have been configured appropriately to pull uids and gids from LDAP.

• newer version control systems like git do not require any further provisioning in order for the user to push into the central repository since they can ride over SSH...

• but a legacy CVS system requires provisioning an account in the CVS writers file in various places

• a login account for a Linux cluster at each of the 10 LIGO Data Grid computing sites is provisioned, usually the account is hosted on storage exposed via NFS. These are separate logins managed by 10 distinct sets of administrators.

• each of the computing sites provisions some type of local storage on each of the cluster head nodes and also a user-dedicated local scratch space on each of the cluster worker nodes. For example on the cluster at Milwaukee we would have /people/scott.koranda on the head node(s) and /localscratch/scott.koranda on each of the worker nodes.

• a number of grid tools including GridFTP, Grid-enabled OpenSSH, and others use a type of ACL file called a grid-mapfile. These files need to be provisioned with an entry like

/DC=org/DC=ligo/OU=People/CN=scott.koranda@LIGO.ORG scott.koranda

Typically there should be a grid-mapfile for each instance of each service at each site. The composition of the grid-mapfiles could depend on the groups to which a user belongs. For example, Scott Koranda only gets an entry for one particular GridFTP server because he is in the group that analyzes a particular type of data.

• Since LIGO members are automatically qualified to run on the Open Science Grid there is also a provisioning of the DN above into the LIGO VOMS server (only used for accessing OSG resources, not LIGO resources).