PNCE Logo Instructions for Group Computer Managers

Instructions for Designated Group Computer Managers

The following describes scripts written to assist designated group computer managers in managing their group(s). Currently, the list of commands is rather limited, but hopefully growing. If you are not a designated group computer manager, there is really no need for you to read any of this --- the scripts themselves are only weakly protected, but the commands they execute will fail unless your account has the proper privileges, which it won't unless you are a group manager. Requests for modifying the list of managers for a group should be sent via physhelp facility.

Overview of Concepts and Terminology

Tasks

An Overview of Concepts and Terminology for Group Managers

designated group computer manager
Sometimes abbreviated as just group manager, this is probably you if you are reading this. In an attempt to enable some routine tasks to be taken care of more expediently, PCS appoints one or two members of a group to be designated group computer manager. These managers are expected to be the primary contact between PCS and the research group, and are authorized to act in the group's principal investigator's name on computer related matters. The PI or existing group managers may request addition of or removal of an user from the list of group managersvia the physhelp facility.

All management questions regarding computing resources of the group in the PNCE-Unix cluster are referred to these managers. In particular, group managers determine which users have access to group computing resources (ie control the membership of the group as far as PNCE-Unix cluster is concerned). They also have control over all the disk space owned by a group, and can request modification of the quota for an user's groupspace, or for a project's groupspace, or request creation of new project groupspaces. We also hope that they will be able to provide some basic user support for users within their group. Users are encourage to go with more basic questions to their group manager, who hopefully will have dealt with the issue before and can answer it based on what they already know. To facilitate this arrangement, PCS will try to give preferential treatment to requests coming from group managers, so that if the group manager does not know how to handle an issue, they can contact PCS who will show both the original user and the group manager how to answer that question in a timely manner.

The group management position is primarily administrative, dealing with requests for people to join (and figuring out who should be removed from) the group. Computer savvy is nice but not required. The computer manager should be fairly available, as PCS will not approve requests for membership without hearing from the group manager. The group manager does not have tremendous authority, some groups use secretaries or graduate students to fill the role.

group resources
Group resources refer to all computing resources accessible to the PNCE-Unix cluster which the group has a right to use. It includes resources which the group owns and brings to the cluster as well as resources that belong to the cluster (or a subcluster such as the NSCP project) which the group is authorized to use. Resources include:

In the current model, users get access to all of the resources listed above (except for groupspace and project areas) or none of it depending upon whether they are a member of the PNCE-Unix group or not. Access to groupspace and project areas can be more finely controlled.

PNCE-Unix group
Often abbreviated as simply group, this represents the collection of users which the computer acknowledges as having certain access rights. In actually, it is not a single group but a collection of five or so groups of different types (governing different types of accesses), one of which is the standard Unix /etc/group group. For simplicity's sake, these various groups are named the same and have the same members--- all this is handled by the various scripts, and the group manager can simply think of this as a single group akin to the standard Unix groups.

Each distinct research group entity (as defined by PCS; for questions/comments regarding this breakdown of the department please submit a physhelp request) has a PNCE-Unix group which should roughly consist of all members of the research group. It grants login access to your groups designated login machines, use of the group's printers, access to NSCP resources if your group is a shareholder in NSCP, etc. All faculty, staff, research associates, graduate students, and undergraduate students who are actively working with your group on its research activities should probably belong to this group. Colleagues outside the department can also be given membership in this group if you wish them to have access to your group's resources; note that they need to already have a Glue/PNCE-Unix account before they can be added to the group. Members of the physics department are eligible for a PNCE-Unix account; and most other people on campus shuld be able to obtain a Glue account. Colleagues not officially associated with the campus (or those otherwise unable to obtain a PNCE-Unix/Glue account), may apply for a sponsored account following the standard account request procedure followed by a physhelp request from you indicating that you wish to sponsor them.

In addition, PCS can create groups which you can manage for various projects that your group may have. These are primarily for instances in which you wish people working on a certain project to have access to disk space or other resources which the rest of the group should not have access to.

Group disks
All disk space brought into the cluster by a group is considered to be for the use of that group (with exception of some disk space on each host required for running of the operating system). To facilitate management of this resource, PCS has imposed a general structure on the group disk space which gives some consistency of directory structures across groups yet hopefully has sufficient flexibility to meet all your groups needs.

The basic structural division is between groupspace and data disks. Groupspace is intended to be the primary repository of files related to your groups research activities. Most groups (all original NSCP-II shareholders) have groupspace in AFS space and served off of departmental file servers, although some recent additions to the PNCE-Unix cluster have their groupspace in NFS space served off one of their login machines. Either way, your groups groupspace (if it has any) is located under group/xxx, where xxx is the abbreviation for your groupname. Data disks are generally large filesystems mounted locally on a login machine, and located at /data/hostname n where hostname is the machine it is mounted on, and n is a digit indicating which disk on that host it is.

Groupspace
All NSCP-II shareholding groups and some newer additions to PNCE-Unix have groupspace, located at /group/xxx where xxx is the abbreviation for the groupname. The term is also used sometimes to refer to an user's directory in the user section of the groups groupspace.

Your groups groupspace should be structured along these lines:

As group manager, you have supervisory access to all files in the above directory hierarchy, although for safety reasons your read/write access is by default restricted (although you can turn it on via the fs command). Note that you do not have access to anyone's home space other than your own.

Group projects
This term refers to volumes mounted below the project directory in your groupspace. It is intended to be used for multiperson research projects so that everyone involved in the project can be granted read write access without opening up their user groupspace to others. It may also assist in managing resource allocation, as each project directoy and user directory can be assigned quotas. You can also request (via physhelp) for a group to be created associated with that project to facilitate in governing access.

Data Disks
Data disks are local storage disks mounted on login clients. They all reside in AFS space, and are not backed up unless requested (and such backup requests will require an FAS to charge backup costs to). They are generally intended for the storage of large data files.

Instructions for Group Managers by Task

Listing what PNCE-Unix groups you manage

This can be done most easily with the manage_group utility in interactive mode. Indeed, when the utility is started in interactive mode, the first thing it does is greet you and list which groups you manage. If you need to see them in the middle of a session, there is the groups command which will print out that list again.

Managing the membership of your groups

This can be done through the manage_group utility (located in /dept/phys/local/bin). Currently, only an interactive mode is available. To use, type manage_group without any arguments at the command line. The system should then greet you and display a list of groups which you manage, and then give you the mg> prompt.

At the mg> prompt, you can issue various commands. The groups command will redisplay the list of groups which you manage. The help command will display a brief summary of the interactive mode commands, and the quit command will exit the program.

The list command will list the members of the requested groups. If you manage more than one group, the utility will ask you which group or groups you wish to list. You should enter all the groups you want membership lists of on a single line, separated by spaces or commas. If multiple groups are specified, the command returns the union of the memberships of the specified groups. If you only manage a single group, that group will be implicitly used by the command without prompting you.

The add and remove commands add and remove, respectively, users from groups. If you manage more than one group, the utility will prompt you for the name(s) of groups you wish to add/remove user(s) to/from. If you wish to add/remove people to/from more than one group, enter the names of all the groups on the same line separated by spaces or commas. If you only manage a single group, the system will assume that is the group you wish to add people to without prompting you.

The system will then ask you for a list of users to add to/remove from the aforementioned group(s). Enter the usernames of the people you wish to add or remove. Again, if you wish to add or remove more than one person, enter the usernames all on one line separated by spaces or commas.

If more than one user or group is specified, all named users are added to or removed from all named groups. After you enter the groups and/or users, the system will print out what it interprets you as wishing to do, and require you to confirm the action by typing y before it will process the request.

You must be listed as a manager of a group to add/remove/ or list users, and the user's Glue/PNCE-Unix account must exist prior to issuing this command to add them to groups.

Managing your groupspace

Group managers are responsible for managing their groups groupspace. This includes such tasks as

Currently, there are no scripts to assist in any of that. Some aspects of this management are complicated by the fact that many items which look like directories are in actuality AFS volumes (eg, anything which has its own quota is a volume, not a directory) which require special handling. Therefore, actions which require the creation/deletion of a volume, or the changing of a quota on a volume, currently must be done by PCS staff, but will be done on your behalf as a group manager if you submit a physhelp request. This includes creation, deletion, and quota modification of user groupspace, project space, and volumes underneath the software directory. However, group managers should already have full access to all the existing files in the group directory structure, although by default this access is disabled until you activate it with the fs command.

In particular, this means that once the volume for your groups web pages is created, you have access to all your groups web pages. Similarly, once a volume is created for a software package, you have complete access to it for installation and other purposes.

To view the existing quota on an user's groupspace, issue the command /usr/bin/afsws/fs listquota /group/xxx/user/username replacing xxx with your group abbreviation and username with the user in question's login name.

To create, remove, or modify quotas submit a physhelp request.

Managing what happens when group members log in

It is often convenient to have some control over the environment of users in your group. In particular, you may wish to have a certain command alias available to all members of your group, or to have a certain directory in everyone's path.

To assist in this, during everyone's log in process on a PNCE-Unix machine, the system will execute the csh script in /group/xxx/software/bin/cshrc if the file exists and the user is a member of group xxx. This takes place before the user's personal (.cshrc.mine) instructions run, so the user can override your instructions if they so desire, but if not they will get your commands.

As group manager, you have write access to this file.


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