Hosts

A host is an individual computer in the cluster.

Each host may have more than one processor. Multiprocessor hosts are used to run parallel jobs. A multiprocessor host with a single process queue is considered a single machine, while a box full of processors that each have their own process queue is treated as a group of separate machines.

Host commands

The following LSF commands are useful when working with hosts in your LSF cluster:

  • lsload: to view the load on hosts
  • lshosts: to view configuration information about hosts in the cluster, including the number of CPUs, model, type, and whether the host is a client or server
  • bhosts: to view batch server hosts in the cluster
    Tip: The names of your hosts should be unique. They should not be the same as the cluster name or any queue defined for the cluster.

Types of LSF hosts

LSF supports three types of hosts:
Server
A server host is capable of submitting and running jobs. It runs sbatchd to execute server requests and apply local policies.

Use the lshosts command to view hosts that are servers (server=Yes).

Server hosts are defined in the lsf.cluster.cluster_name file by setting the value of server to 1.

Client
A client hosts is only capable of submitting jobs to the cluster. They run LSF commands and act only as submission hosts; they do not execute jobs or run LSF daemons.

Use the lshosts command to view hosts that are clients (server=No).

Client hosts are defined in the lsf.cluster.cluster_name file by setting the value of server to 0

Management
A Management host is an LSF server host that acts as the overall coordinator for that cluster. All LSF daemons (including the mbatchd daemon) run on the management host. The LIM on the management host is the management host LIM. The host LIM runs from the management host.

Each cluster has one management host to do all job scheduling and dispatch. If the management host goes down, another LSF server in the cluster becomes the management host.

Use the lsid command to view the management host name.

The management host is the first host that is listed in the lsf.cluster.cluster_name file or is defined along with other candidate management hosts by LSF_MASTER_LIST in lsf.conf.

Submitting and executing LSF jobs

Additionally, when you run LSF jobs, you do so by running commands from the host where you submit the job, which can be different from the host that actually runs or executes the job:
Submission
Where jobs are submitted to the cluster. Client hosts and server hosts can act as submission hosts.
Use these command for job submission:
  • bsub: to submit a job
  • bjobs: to view jobs that are submitted

Jobs are submitted using the bsub command or from an application that uses the LSF API.

Execution
Where a job runs or executes. The execution host can be the same as the submission host, or can be separate. All execution hosts are server hosts.

Use the bjobs LSF command to view where a job runs.