1. Introduction

The Advance Reservation Service (ARS) provides a web-based interface to batch schedulers on computational resources across the High Performance Computing Modernization Program (HPCMP). This service allows allocated users to reserve resources for later usage, at specific times, for specific durations, and works in tandem with selected schedulers to allow restricted access to those reserved resources. This document provides a guide to authorized users who want to take advantage of the ARS.

2. Logging In

The first step in using the ARS is to authenticate to the server so that the user's allocations across supported systems can be identified. The HPCMP's OpenID service is used to authenticate users upon accessing the ARS URL (https://reservation.hpc.mil). After reading and accepting the DOD banner, the user can authenticate by selecting either the PKI/CAC option or the Kerberos/YubiKey option as shown on Screen 2 as follows.

Screen 1: Notice and Consent Page

Screen 2: OpenID Connect Login Method Selection

Depending on the user's selection of the PKI/CAC login method or the Kerberos/YubiKey login method, a CAC PIN entry prompt (Screen 3) or a Kerberos principal, password, and YubiKey token code entry form (Screen 4) is presented, respectively, as shown below. In the case of the Kerberos/YubiKey login method selection, the user should enter the YubiKey token last after the preceding fields have been entered.

Screen 3: OpenID Connect PKI/CAC PIN Entry Prompt

Screen 4: OpenID Connect Kerberos Entry Prompt

3. Selecting a System

Upon successful authentication, the user will be presented with a set of systems from which to choose. Users are required to have a valid account, with both Portal to the Information Environment (pIE) and local authorization, and be on a project with remaining allocation in order to generate reservations. If either of these criteria is not met, the system will not be presented as an option. This means that even if pIE shows a user assigned to a system, the user may not be able to generate reservations on that system due to DSRC, or remaining allocation restrictions. Screen 5 shows the system selection screen shot. If the selected system is unavailable for any reason, the user will be notified immediately after selection, and another system can then be selected.

Screen 5: System Selection

4. Making a Reservation

Once a system is selected, a calendar is presented for the current month with a node availability indicator, so that users can find a day (and timeframe) that has the number of required nodes available. This is the reservation request page and reservations can be made only on this page. By clicking on the nodes available indicator for a day on the calendar, the user will be shown the hourly availability of nodes (Screen 14). A display of future months is available via the "Calendar" menu tab on the side screen. When the "Calendar" menu tab is clicked, a new window is displayed (Screen 13) with a scrollable month view to see long-term node availability. Reservations may not be made more than three months in advance, so the "Calendar" view will only display up to three months into the future. Screen 6 shows the calendar display for the reservation request page.

Screen 6: Reservation Request Page

4.1. Reservation Options

The remainder of the reservation request page is shown in Screen 8 below. On this extended screen the user is presented with:

• A choice whether to allow additional users on the same project to share the reservation
• A selection menu listing projects with remaining allocation on the selected host
• The number of nodes required for the reservation
• The start date and time for the reservation
• The end date and time for the reservation
• A reservation type (for interactive or batch reservations)
• A list of licensed software for which licenses can be reserved, with a license count field for each piece of licensed software

Some systems offer the ability to select different node types. There are 2 different methods in ARS in which this may be available. First, as selection is shown for each node type available, as seen in screen 8. The user can reserve multiple different node types for a single reservation, or a single node type by leaving the selection 0. Screen 7 shows the nodes required option followed by the memory selection. Users can select a single node type for the reservation for the number of nodes requested.

Screen 7: Node Type Selection

All of these fields, except software license fields, are required to request a reservation. If the "Multiple Users" option is selected, the user will be forwarded to a Multiple User Selection form (Screen 9) as shown below. Only users that are on the same project selected will be made available. Sharing the reservation details and subsequent notifications to additional users is left entirely to the discretion of the requesting user and is not a capability provided by ARS. Upon submission of the request, the data is validated against existing reservations on the selected system and then submitted to the requested machine. If software licenses are required, those are checked for availability first, before requesting actual reservations at the specified host. If requested licenses are not available at the specified time, the reservation will not be requested at the host, and the user will be notified that licenses are not available. At the conclusion of the reservation period, the project will be billed in CPU hours for the duration of the reservation. Jobs submitted against the reservation that charge to another project (not associated with the reservation), will be billed against the projects specified at job submittal time. All other CPU hours, whether for actual jobs run or for idle time, will be billed to the project noted during the creation of the reservation. If the reservation cannot be made at the requested system, the user will be notified of that fact.

Default limits on reservations are:

• A single user cannot use more than 50% of ARS-assigned resources at one time.
• A single reservation cannot be more than 168 hours in length.
• User's project allocation will be checked at reservation creation time for validity.
• Reservations must be made at least 96 hours prior to reservation commencement.
• Reservations must be deleted at least 8 hours prior to their commencement; otherwise, the user/project will be billed for the reservation.
• A single user can have up to four reservations active at any time on a specific system. However, as stated above, no single user can use more than 50% of ARS assigned resources at any one time.

Screen 8: Reservation Request Page (continued)

4.2. Selecting Multiple Users

Screen 9: Multiple User Selection Page

5. Reservation Confirmation

Upon successful completion of the reservation request, a confirmation page is presented. Additionally, an email will be sent notifying the user of all pertinent data concerning the reservation. Email will also be sent 2 days prior and 2 hours prior to reservation start. Note: It is the user's responsibility to make use of the reserved nodes. The user must log onto the selected system and submit a job to the reservation explicitly by using the queue name generated by PBS Pro (sent via email) at the time of the reservation creation.

qsub -q R15 myjob

PBS Pro supports interactive jobs and if selected via the pull down menu, the nodes can be used interactively by the -I option to the above commands. Screen 10 shows the reservation confirmation page.

Screen 10: Reservation Confirmation Screen

6. Cancelling a Reservation

Reservations can be canceled by selecting the "Cancel Reservation" menu (See Screen 11) on the left. Specific reservations can be canceled by checking the box associated with the reservation and then clicking on the "Cancel Reservations" button. All reservations checked will be canceled at the remote system, and users will not be charged for the reservation if it is canceled at least 8 hours before the reservation is to commence. Otherwise, the user will be billed for the entire reservation.

Screen 11: Reservation Cancellation Screen

6.1. Cancellation Confirmation

Upon successful cancellation, the user will be shown a cancellation confirmation screen (Screen 12) and sent an email.

Screen 12: Reservation Cancellation Success Screen

7. The Reservation Calendar

The reservation calendar (Screen 13) shows reservations that are currently in place for all users of the selected system. This screen allows users to discern time slots available for nodes during the reservation request process.

Screen 13: Reservation Calendar Screen

7.1. Viewing Daily Details

The reservation calendar (Screen 13) shows reservations that are currently in place for all users of the selected system. This screen allows users to discern time slots available for nodes during the reservation request process.

Screen 14: Reservation Daily Detail Screen

7.2. Viewing Your Reservations

The reservations for a user can be displayed by using the reservation hourly detail screen (Screen 15) by selecting the node available indicator on the daily detail screen.

Screen 15: Reservation Hourly Detail Calendar Screen

7.3. Searching for Job Slots

Using the Job Slot Search (JSS) feature of ARS, available time slots for reservation requests may be obtained by providing the number of nodes, wall time, project and other desired reservation parameters. Once successfully authenticated into ARS and selecting the desired system to request a reservation, selecting the "Job Slot Search (JSS)" button from the side menu will display the Job Slot Search form (Screen 16) as displayed below.

Screen 16: Job Slot Search Screen

After entering and submitting the number of nodes requested, wall time requested, desire to include additional users, requested software licenses, and reservation type, the user is either prompted to first select the additional users (Screen 9) if multiple users were requested, or to select from a list of available slots for the reservation as shown below in Screen 17. If the multiple users are requested, the list of available reservation slots is displayed after selecting the additional users.

Screen 17: Job Slot Search Results Screen

After reviewing the list of available job slots matching the submitted reservation parameters on the Job Slot Search Results Screen (Screen 17), the user may select either a desired job slot or the "Find More Slots" option. If the "Find More Slots" option is selected, the user is presented with the next available set of job slots that met the submitted reservation parameters. The user may continue to select this option until a desirable job slot is found. Upon selecting and submitting a desired job slot, the user is then prompted to confirm that selection on a confirmation screen (Screen 18) as shown below.

Screen 18: Confirm Job Slot Screen

Upon successful completion of the reservation request, a confirmation page is presented (Screen 19). Additionally, an email will be sent notifying the user of all pertinent data concerning the reservation. Email will also be sent 2 days prior and 2 hours prior before the reservation starts.

Screen 19: Reservation Confirmation Screen