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To start a job, the ecflow_server uses the content of the ECF_JOB_CMD variable.
By modifying this variable, it is possible to control where and how a job file will run.
The command should be used in conjunction with the variable ECF_JOB and ECF_JOBOUT.
The ECF_JOB variable contains the job file path and ECF_JOBOUT contains
the path of a file where the output of the job will be written.  The default command:


 ECF_JOB_CMD = %ECF_JOB% 1> %ECF_JOBOUT% 2>&1 &
Let us run the tasks on a remote machine. For that, we could use the UNIX command ssh.
We would like the name of the host to be defined by a variable called HOST.
We assume that all the files are visible on all the hosts, e.g. using NFS.

In the examples below replace the string ?????? with a host name of your choice.


The environment of a task running on a remote host can be different from that of a task running locally.
It depends on how your system is set up. The head.h  should already be using the correct PATH, to allow child commands to be used.
If not add the following line into your head.h file before the call to ecflow_client –init

> export PATH=$PATH:/usr/local/apps/ecflow/%ECF_VERSION%/bin

To use ssh requires your public key to be available on the destination machine.
Check if you can log on to the remote machine through ssh without a password check.
If you need to enter a password you will need to add your public key on the destination machine. To do this issue the following commands:


no password for ssh connection
REMOTE_HOST=??????  # change me
ssh $USER@$REMOTE_HOST mkdir -p \$HOME/.ssh      # if you are prompted for a password use your Training password that was provided
cat $HOME/.ssh/id_rsa.pub || ssh-keygen -t rsa -b 2048
cat $HOME/.ssh/id_rsa.pub | ssh $USER@$REMOTE_HOST 'cat >> $HOME/.ssh/authorized_keys'

Modify the family f5 so that all its tasks will run on another machine in the classroom.

    

Text

# Definition of the suite test
suite test
 edit ECF_INCLUDE "$HOME/course"
 edit ECF_HOME    "$HOME/course"
 limit l1 2

 family f5
     edit HOST ??????
     edit ECF_OUT /tmp/$USER
     edit ECF_JOB_CMD "ssh %HOST% 'mkdir -p %ECF_OUT%/%SUITE%/%FAMILY% && %ECF_JOB% > %ECF_JOBOUT% 2>&1 &'"
     inlimit l1
     edit SLEEP 20
     task t1
     task t2
     task t3
     task t4
     task t5
     task t6
     task t7
     task t8
     task t9
 endfamily
endsuite

If your login shell is csh, you should define ECF_JOB_CMD as:

edit ECF_JOB_CMD "ssh %HOST% 'mkdir -p %ECF_OUT%/%SUITE%/%FAMILY%; %ECF_JOB% >& %ECF_JOBOUT%'"

Python

In python modify the function create_family_f5() created in the earlier page, to add HOST,ECF_OUT,ECF_LOGHOST,ECF_LOGPORT, and ECF_JOB_CMD:

$HOME/course/test.py
import os
from ecflow import Defs,Suite,Family,Task,Edit,Trigger,Complete,Event,Meter,Time,Day,Date,Label, \
                   RepeatString,RepeatInteger,RepeatDate,InLimit,Limit
         
def create_family_f5() :
    return Family("f5",
            InLimit("l1"),
            Edit(SLEEP=20,
                 HOST='?????',
                 ECF_OUT = '/tmp/%s' % os.getenv("USER"),
                 ECF_LOGHOST='%HOST%',
                 ECF_LOGPORT='?????',  # port=$((35000 + $(id -u))) run this on the command line
                 ECF_JOB_CMD="ssh %HOST% 'mkdir -p %ECF_OUT%/%SUITE%/%FAMILY%; %ECF_JOB% > %ECF_JOBOUT% 2>&1 &'"),
            [ Task('t{}'.format(i)) for i in range(1,10) ] )
     
print("Creating suite definition")  
home = os.path.join(os.getenv("HOME"),"course")
defs = Defs(
        Suite("test",
            Edit(ECF_INCLUDE=home,ECF_HOME=home),
            Limit("l1",2),
            create_family_f5()))
print(defs)
 
print("Checking job creation: .ecf -> .job0") 
print(defs.check_job_creation())
 
print("Checking trigger expressions")
assert len(defs.check()) == 0,defs.check()
 
print("Saving definition to file 'test.def'")
defs.save_as_defs("test.def")

Logserver

 We can view the output on the remote machine (class??) by using a log server.

This assumes you have defined variables ECF_LOGHOST and ECF_LOGPORT in your definition.

 Launch the log server on a remote machine:

ssh $USER@class01 /usr/local/apps/ecflow/5.5.1/bin/ecflow_logserver.sh -d /tmp/$USER -m /tmp/$USER:/tmp/$USER

What to do

  1. Modify PATH environment variable in head.h
  2. Change the suite definition
  3. Replace the suite definition
  4. It may not work immediately. Have a look in the file $HOME/course/host.port.ecf.log to see why.
  5. Add a uname -n to your ECF script to see what machine the task is running on.
  6. What do you need to do in order to have the task /test/f5/t9 run on another machine? Try your solution.
  7. Create a log server, to access the remote output

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