3.2.2 Scheduling Dictionary
| Account | |||
| Definition: | A credential also known as project ID. Multiple users may be associated a single account ID and each user may have access to multiple accounts. (See credential definition and ACCOUNTCFG parameter.) | ||
| Example: | ACCOUNT=hgc13 | ||
| ACL (Access Control List) | |||
| Definition: | In the context of scheduling, an access control list is used and applied much as it is elsewhere. An ACL defines what credentials are required to access or use particular objects. The principal objects to which ACLs are applied are reservations and QoS's. ACLs may contain both allow and deny statements, include wildcards, and contain rules based on multiple object types. | ||
| Example: | Reservation META1 contains 4 access statements.
Allow jobs owned by user john or bob
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| Allocation | |||
| Definition: | A logical, scalar unit assigned to users on a credential basis, providing access to a particular quantity of compute resources. Allocations are consumed by jobs associated with those credentials. | ||
| Example: | ALLOCATION=30000 | ||
| Class | |||
| Definition: | (see Queue) A class is a logical container object that holds jobs allowing a site to associate various constraints and defaults to these jobs. Class access can also be tied to individual nodes defining whether a particular node will accept a job associated with a given class. Class based access to a node is denied unless explicitly allowed via resource manager configuration. Within Moab, classes are tied to jobs as a credential. | ||
| Example: | job cw.073 is submitted to class batch
node cl02 accepts jobs in class batch reservation weekend allows access to jobs in class batch |
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| CPU | |||
| Definition: | A single processing unit. A CPU is a consumable resource. Nodes typically consist of one or more CPUs. (same as processor ) | ||
| Credential | |||
| Definition: | An attribute associated with jobs and other objects
that determines object identity. In the case of schedulers and resource
managers, credential based policies and limits are often established. At
submit time, jobs are associated with a number of credentials such as user, group , account , QoS, and class. These job credentials subject
the job to various polices and grant it various types of access.
In most cases, credentials set both the privileges of the job and the ID of the actual job executable. |
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| Example: | Job cw.24001 possesses the following credentials:
USER=john;GROUP=staff;ACCOUNT=[NONE];
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| Disk | |||
| Definition: | A quantity of local disk available for use by batch jobs. Disk is a consumable resource. | ||
| Execution Environment | |||
| Definition: | A description of the environment in which the executable is launched. This environment may include attributes such as the following:
an executable command line argumentss input file output file local user ID local group ID process resource limits | ||
| Example: | Job cw.24001 possesses the following execution environment:
EXEC=/bin/sleep;ARGS="60";
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| Fairshare | |||
| Definition: | A mechanism that allows historical resource utilization information to be incorporated into job priority decisions. | ||
| Fairness | |||
| Definition: | The access to shared compute resources that each user is granted. Access can be equal or based on factors such as historical resource usage, political issues, and job value. | ||
| Group | |||
| Definition: | A credential typically directly mapping to a user's Unix group ID. | ||
| Job | |||
| Definition: | The fundamental object of resource consumption. A job contains
the following components:
A list of required consumable resources A list of resource constraints controlling which resources may be allocated to the job A list of job constraints controlling where, when, and how the job should run A list of credentials An execution environment |
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| Job Constraints | |||
| Definition: | A set of conditions that must be fulfilled for the job to
start. These conditions are far reaching and may include one or more
of the following:
When the job may run. (After time X, within Y minutes.) Which resources may be allocated. (For example, node must possess at least 512 MB of RAM, run only in partition or Partition C, or run on HostA and HostB.) Starting job relative to a particular event. (Start after job X successfully completes.) |
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| Example: | RELEASETIME>='Tue Feb 12, 11:00AM'
DEPEND=AFTERANY:cw.2004 NODEMEMORY==256MB |
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| Memory | |||
| Definition: | A quantity of physical memory (RAM). Memory is provided by compute nodes. It is required as a constraint or consumed as a consumable resource by jobs. Within Moab, memory is tracked and reported in megabytes (MB). | ||
| Example: | Node node001 provides the following resources:
PROCS=1,MEMORY=512,SWAP=1024 Job cw.24004 consumes the following resources per task:
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| Node | |||
| Definition: | A node is the fundamental object associated with compute resources. Each node contains the following components:
A list of consumable resources A list of node attributes |
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| Node Attribute | |||
| Definition: | A node attribute is a non-quantitative aspect of a node. Attributes typically describe the node itself or possibly aspects of various node resources such as processors or memory. While it is probably not optimal to aggregate node and resource attributes together in this manner, it is common practice. Common node attributes include processor architecture, operating system, and processor speed. Jobs often specify that resources be allocated from nodes possessing certain node attributes. | ||
| Example: | ARCH=AMD,OS=LINUX24,PROCSPEED=950 | ||
| Node Feature | |||
| Definition: | A node feature is a node attribute that is typically specified locally via a configuration file. Node features are opaque strings associated with the node by the resource manager that generally only have meaning to the end-user, or possibly to the scheduler. A node feature is commonly associated with a subset of nodes allowing end-users to request use of this subset by requiring that resources be allocated from nodes with this feature present. In many cases, node features are used to extend the information provided by the resource manager. | ||
| Example: | FEATURE=s950,pIII,geology
(This may be used to indicate that the node possesses a 950 MHz Pentium III processor and that the node is owned by the Geology department.) |
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| Processor | |||
| Definition: | A processing unit. A processor is a consumable resource. Nodes typically consist of one or more processors. (same as CPU) | ||
| Quality of Service (QoS) | |||
| Definition: | An object that provides special services, resources, and so forth. | ||
| Queue | |||
| Definition: | (see Class) | ||
| Reservation | |||
| Definition: | An object that reserves a specific collection or resources for a specific timeframe for use by jobs that meet specific conditions. | ||
| Example: | Reserve 24 processors and 8 GB of memory from time T1 to time T2 for use by user X or jobs in the class batch. | ||
Resource
| Definition: |
Hardware, generic resources such as software, and features available on a node, including memory, disk, swap, and processors. |
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| Resource, Available | |||
| Definition: | A compute node's configured resources minus the maximum of the sum of the resources utilized by all job tasks running on the node and the resources dedicated; that is, R.Available = R.Configure - MAX(R.Dedicated,R.Utilized).
In most cases, resources utilized will be associated with compute jobs that the batch system has started on the compute nodes, although resource consumption may also come from the operating system or rogue processes outside of the batch system's knowledge or control. Further, in a well-managed system, utilized resources are less than or equal to dedicated resources and when exceptions are detected, one or more resource limit policies is activated to preempt the jobs violating their requested resource usage. |
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| Example: | Node cl003 has 4 processors and 512 MB of memory. It
is executing 2 tasks of job clserver.0041 that are using 1
processor and 60 MB of memory each. One processor and 250 MB of memory
are reserved for user jsmith, but are not currently in use.
Node cl003's resources available to user jsmith:
Node cl003's resources available to a user other than jsmith:
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| Resource, Configured | |||
| Definition: | The total amount of consumable resources that are available on a compute node for use by job tasks. | ||
| Example: | Node cl003 has 4 processors and 512 MB of memory. It
is executing 2 tasks of job clserver.0041 that are using 1
processor and 60 MB of memory each. One processor and 250 MB of memory
are reserved for user jsmith but are not currently in use.
Node cl003's configured resources:
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| Resource, Consumable | |||
| Definition: | Any object that can be used (that is, consumed and thus made unavailable to another job) by, or dedicated to a job is considered to be a resource. Common examples of resources are a node's physical memory or local disk. As these resources may be given to one job and thus become unavailable to another, they are considered to be consumable. Other aspects of a node, such as its operating system, are not considered to be consumable since its use by one job does not preclude its use by another.
Note that some node objects, such as a network adapter, may be dedicated under some operating systems and resource managers and not under others. On systems where the network adapter cannot be dedicated and the network usage per job cannot be specified or tracked, network adapters are not considered to be resources, but rather attributes. Nodes possess a specific quantity of consumable resources such as real memory, local disk, or processors. In a resource management system, the node manager may choose to report only those configured resources available to batch jobs. For example, a node may possess an 80-GB hard drive but may have only 20 GB dedicated to batch jobs. Consequently, the resource manager may report that the node has 20 GB of local disk available when idle. Jobs may explicitly request a certain quantity of consumable resources. |
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| Resource, Constraint | |||
| Definition: | A resource constraint imposes a rule on which resources can be be used to match a resource request. Resource constraints either specify a required quantity and type of resource or a required node attribute. All resource constraints must be met by any given node to establish a match. | ||
| Resource, Dedicated | |||
| Definition: | A job may request that a block of resources be dedicated while the job is executing. At other times, a certain number of resources may be reserved for use by a particular user or group. In these cases, the scheduler is responsible for guaranteeing that these resources, utilized or not, are set aside and made unavailable to other jobs. | ||
| Example: | Node cl003 has 4 processors and 512 MB of memory. It
is executing 2 tasks of job clserver.0041 that are using 1
processor and 60 MB of memory each. One processor and 250 MB of memory
are reserved for user jsmith but are not currently in use.
Node cl003's dedicated resources are:
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| Resource, Utilized | |||
| Definition: | All consumable resources actually used by all job tasks running on the compute node. | ||
| Example: | Node cl003 has 4 processors and 512 MB of memory. It
is executing 2 tasks of job clserver.0041 that are using 1
processor and 60 MB of memory each. One processor and 250 MB of memory
are reserved for user jsmith but are not currently in use.
Node cl003's utilized resources are:
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| Swap | |||
| Definition: | A quantity of virtual memory available for use by batch jobs. Swap is a consumable resource provided by nodes and consumed by jobs. | ||
| Task | |||
| Definition: | An atomic collection of consumable resources. | ||
| User, Global | |||
| Definition: | The user credential used to provide access to functions and resources. In local scheduling, global user IDs map directly to local user IDs. | ||
| User, Local | |||
| Definition: | The user credential under which the job executable will be launched. | ||
| Workload | |||
| Definition: | Generalized term. | ||