A persistent problem experienced with proxies expiring for long term jobs on the SAGrid VO has been resolved. A user must create a proxy in order to submit jobs to the Grid. However the proxy will expire after a pre-determined time (default 12 hours) and the job will be terminated if it is still running. In order to allow jobs to run for longer a method of proxy renewal must be used. In the past it was found that this method did not work but only recently were we able to determine that the CNAF MyProxy server did not appear to be honouring requests for renewal by SAGrid proxies. By changing the MyProxy server to the INFN we were able to resolve this issue.
Creating a long term proxy is simple. Create a short term (1 hour) local proxy:
voms-proxy-init --voms sagrid -valid 1:00
Now create a long term (168 hours) proxy on the MyProxy server:
myproxy-init -s myproxy.ct.infn.it -d -n
You will need to put the following line in your JDL file:
MyProxyServer = "myproxy.ct.infn.it";
Then submit your job as normal. You will need a valid short term proxy to carry out any local commands or to check the status of your long term proxy. If your local proxy expires just create another one.
To check the status of your long term proxy use the following command:
myproxy-info -s myproxy.ct.infn.it -d
If your long term proxy looks like it will expire before your job has finished then you can extend it's lifetime by running the init command again:
myproxy-init -s myproxy.ct.infn.it -d -n
NB. When using long term proxies you do not need to create a delegation user ID.
Example:
1) The user creates a proxy certificate on the local user interface portal.
2) A long term proxy is created on the remote proxy server and ‘signed’ with the user’s credentials. This will become the official proxy certificate for the job.
3) Using the local proxy the user submits the job to the WMS which in turn submits it to the relevant CE.
4) The user’s local proxy expires, however the job proxy renewal is now dealt with automatically via the long term proxy server. The user can create a new local proxy at a later stage for job status monitoring or retrieval.
2) A long term proxy is created on the remote proxy server and ‘signed’ with the user’s credentials. This will become the official proxy certificate for the job.
3) Using the local proxy the user submits the job to the WMS which in turn submits it to the relevant CE.
4) The user’s local proxy expires, however the job proxy renewal is now dealt with automatically via the long term proxy server. The user can create a new local proxy at a later stage for job status monitoring or retrieval.