FAQ

How to minimize CPU usage of UserAgent service under Windows?

In order to reduce the CPU utilization of the UserAgent under Windows systems,  you can add the following property into the /Path/To/UserAgentWindows/conf/wrapper.conf file:

wrapper.ntservice.process_priority=LOW

The value LOW makes the UserAgent service running in system idle time; more specifically, setting the property wrapper.ntservice.process_priority to the value LOW, causes the threads of the UserAgent service process to be preempted by the threads of any process running in a higher priority class.

For more details, see the related Java Service Wrapper page.

To make sure that the change is effective, you must restart the UserAgent service.

Important: before restarting the service, please make sure the machine is not used by any Grid application (i.e. the machine status for OurGrid is IDLE).

Why does my peer not appear on the WebStatus page?

It could be due to the fact that you have set one or more parameters of your peer.properties file with a wrong value.

Please accurately check the values of your peer.properties file.

A common mistake is to specify latitude/longitude values as DEGREES MINUTES SECONDS form in place of DECIMAL DEGREES one. For instance, if your peer is located at coordinates:

latitude: 41° 52' 00'' N

longitude: 12° 37' 00'' E

in order to set these value inside the peer.properties file, you have to write:

peer.latitude: 41.87

peer.longitude: 12.62

The convertion from DEGREES MINUTES SECONDS to DECIMAL DEGREES can be performed with the formula:

DECIMAL DEGREES = DEGREES + MINUTES / 60 + SECONDS / 3600

How can I exploit my dual core machine?
We have run some experiments in order to figure out what is the best configuration to fully exploit dual core machines.
Considering the results obtained, we suggest to run a UserAgent process for each core, that is in a machine dual core will run two instances of UserAgents in two different ports.
Why does job status remain UNSTARTED?

If the job status remains UNSTARTED for a long time, the possible causes are

  • your machine does not accept connections from the peer using the port that you have specified during the mygrid configuration phase (see the ~/.mygrid/mg.properties file). More information about firewall settings can be found here.
  • you have not specified the full hostname of your machine during the mygrid installation. Check the first entry in the file ~/.mygrid/mg.properties.
  • the Peer's administrator has not loaded the Site Descriptor File (SDF) (i.e., "peer setgums mysite.sfd")
    • SOLUTION: contact the Peer's administrator
  • (unlikely) all the machines in the community are busy/down
    • SOLUTION: contact the Peer's administrator
How do I configure my firewall?

Most of the Linux distribution uses iptables to create rules for packet filtering. In order to allow your machine to receive connections from the peer on a specific port, you must add a rule in your iptables config file:

  1. locate the iptables config file (usually, it is stored in /etc/sysconfig/iptables)
  2. add a new rule to accept connection on port XXX (this port that you have specified during the mygrid configuration phase (see the ~/.mygrid/mg.properties file).)
    1. if your machine accept ssh connections, copy the line with "--dport 22" and paste a new line changing "--dport 22" with "--dport XXX".
    2. else try to add this line: "-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport XXX -j ACCEPT" (rememper to replace XXX, with your mygrid port)
  3. restart iptables
    1. /etc/init.d/iptables restart
Why do I get an error in submitting a job even if the syntax of the JDF is correct?

When submitting a new job with MyGrid you might get the following error:

Job could not be added

Error cause: There's a syntax problem at the source: check line X near word ABC.

If the syntax of the JDF file, related to that job, is correct, it might be possible the error is given by a conflict between a reserved JDF word and a string you used inside the JDF script. For instance, if you label the job with the following:

job:

label: Store

you will get the above error because store is a reserved word.

Search the FAQ:

How can I exploit my dual core machine?
Nov. 8, 2010 by guglielmogg, Italy
We have run some experiments in order to figure out what is the best configuration to fully exploit dual core machines.
Considering the results obtained, we suggest to run a UserAgent process for each core, that is in a machine dual core will run two instances of UserAgents in two different ports.

How do I configure my firewall?
Nov. 8, 2010 by guglielmogg
Most of the Linux distribution uses iptables to create rules for packet filtering. In order to allow your machine to receive connections from the peer on a specific port, you must add a rule in your iptables config file:

1. locate the iptables config file (usually, it is stored in /etc/sysconfig/iptables)
2. add a new rule to accept connection on port XXX (this port that you have specified during the mygrid configuration phase (see the ~/.mygrid/mg.properties file).)
1. if your machine accept ssh connections, copy the line with "--dport 22" and paste a new line changing "--dport 22" with "--dport XXX".
2. else try to add this line: "-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport XXX -j ACCEPT" (rememper to replace XXX, with your mygrid port)
3. restart iptables
1. /etc/init.d/iptables restart

How to minimize CPU usage of UserAgent service under Windows?
Oct. 14, 2010 by guglielmogg
In order to reduce the CPU utilization of the UserAgent under Windows systems, you can add the following property into the /Path/To/UserAgentWindows/conf/wrapper.conf file:
wrapper.ntservice.process_priority=LOW
The value LOW makes the UserAgent service running in system idle time; more specifically, setting the property wrapper.ntservice.process_priority to the value LOW, causes the threads of the UserAgent service process to be preempted by the threads of any process running in a higher priority class.
For more details, see the related Java Service Wrapper page.
To make sure that the change is effective, you must restart the UserAgent service.

Important: before restarting the service, please make sure the machine is not used by any Grid application (i.e. the machine status for OurGrid is IDLE).
Credits: we thank Sergio Rabellino for giving this information.

Why do I get an error in submitting a job even if the syntax of the JDF is correct?
Nov. 8, 2010 by guglielmogg
When submitting a new job with MyGrid you might get the following error:

Job could not be added

Error cause: There's a syntax problem at the source: check line X near word ABC.

If the syntax of the JDF file, related to that job, is correct, it might be possible the error is given by a conflict between a reserved JDF word and a string you used inside the JDF script. For instance, if you label the job with the following:

job:

label: Store

you will get the above error because store is a reserved word.

Why does job status remain UNSTARTED?
Nov. 8, 2010 by guglielmogg, Italy
If the job status remains UNSTARTED for a long time, the possible causes are
* your machine does not accept connections from the peer using the port that you have specified during the mygrid configuration phase (see the ~/.mygrid/mg.properties file). More information about firewall settings can be found here.
* you have not specified the full hostname of your machine during the mygrid installation. Check the first entry in the file ~/.mygrid/mg.properties.
* the Peer's administrator has not loaded the Site Descriptor File (SDF) (i.e., "peer setgums mysite.sfd")
o SOLUTION: contact the Peer's administrator
* (unlikely) all the machines in the community are busy/down
o SOLUTION: contact the Peer's administrator

Why does my peer not appear on the WebStatus page?
Oct. 14, 2010 by guglielmogg
It could be due to the fact that you have set one or more parameters of your peer.properties file with a wrong value.

Please accurately check the values of your peer.properties file.

A common mistake is to specify latitude/longitude values as DEGREES MINUTES SECONDS form in place of DECIMAL DEGREES one. For instance, if your peer is located at coordinates:

latitude: 41° 52' 00' N

longitude: 12° 37' 00' E

in order to set these value inside the peer.properties file, you have to write:

peer.latitude: 41.87

peer.longitude: 12.62

The convertion from DEGREES MINUTES SECONDS to DECIMAL DEGREES can be performed with the formula:

DECIMAL DEGREES = DEGREES + MINUTES / 60 + SECONDS / 3600

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