Difference between revisions of "Daemons"
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==Overview== | ==Overview== | ||
| − | The daemon server provides UF Research Computing users with the space and resources to run long-running processes that do not require a lot of computational power. Please remember that these types of processes cannot be run on the login servers | + | The daemon server provides UF Research Computing users with the space and resources to run long-running processes that do not require a lot of computational power. Please remember that these types of processes cannot be run on the login servers. |
Daemon processes run in the background of a system rather than under the direct control of an interactive user. There are many uses for daemon tasks, from polling the batch system to collecting data from external sources. Daemon tasks are usually long-running or scheduled to run recurrently. They are also characterized by a small computational footprint (i.e., low average CPU and RAM usage). '''Daemon processes should not use 100% of a CPU for extended periods and such processes will be killed without warning.''' | Daemon processes run in the background of a system rather than under the direct control of an interactive user. There are many uses for daemon tasks, from polling the batch system to collecting data from external sources. Daemon tasks are usually long-running or scheduled to run recurrently. They are also characterized by a small computational footprint (i.e., low average CPU and RAM usage). '''Daemon processes should not use 100% of a CPU for extended periods and such processes will be killed without warning.''' | ||
==Access to the daemon server== | ==Access to the daemon server== | ||
| − | Connect to the cluster ( | + | Connect to the cluster (hpg2.rc.ufl.edu) and use the ssh command to access the daemon server. |
| − | <pre>ssh | + | <pre>ssh daemon</pre> |
| − | + | The daemon node is not accessible directly from outside of the cluster. | |
| − | |||
==Running daemon processes== | ==Running daemon processes== | ||
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==Setting up recurring tasks with Cron== | ==Setting up recurring tasks with Cron== | ||
| − | You can schedule a task to run recurrently with Cron, a time-based job scheduler by editing your crontab file on the | + | You can schedule a task to run recurrently with Cron, a time-based job scheduler by editing your crontab file on the daemon server. [[Cron | Click here for more detailed instructions.]] |
Revision as of 13:06, 25 July 2016
Overview
The daemon server provides UF Research Computing users with the space and resources to run long-running processes that do not require a lot of computational power. Please remember that these types of processes cannot be run on the login servers.
Daemon processes run in the background of a system rather than under the direct control of an interactive user. There are many uses for daemon tasks, from polling the batch system to collecting data from external sources. Daemon tasks are usually long-running or scheduled to run recurrently. They are also characterized by a small computational footprint (i.e., low average CPU and RAM usage). Daemon processes should not use 100% of a CPU for extended periods and such processes will be killed without warning.
Access to the daemon server
Connect to the cluster (hpg2.rc.ufl.edu) and use the ssh command to access the daemon server.
ssh daemon
The daemon node is not accessible directly from outside of the cluster.
Running daemon processes
There are two ways to run a process in the background:
1. Add an ampersand (&) to the end of the command
my.process.sh &
2. Start the process and once it is running, type
control-Z + b + g
Setting up recurring tasks with Cron
You can schedule a task to run recurrently with Cron, a time-based job scheduler by editing your crontab file on the daemon server. Click here for more detailed instructions.