The world of CFLT Daemons

The panoply of CFLT Daemons keeps various programs running that are important for the operation of the CFLT. We use the ZMP Daemon system for all of our Daemonic needs.

On each node there is a single CFLT Daemon devoted to monitoring several child application processes. ZMP Daemon commands (zmp_daemon_client) are used to control the starting and stopping of the child processes. There are scripts and command files available to make starting and stopping the children easier for the user. (Also see the "AROX" and "ARMS" utilities for a user interface to the Daemons.) The "daemon" program on the cflt accounts on various platforms provides the most convenient way to start and stop daemon children.

Here are the various Daemons and the children they watch. Also included are the daemon child description file (extension .appl or .APPL) which gives the command script name and output log file name. This file can be found in the common daemon disk area indicated. For the nodes CFLT02, zaxp10, and ZWS016, there exists the flush command which will kill all daemon children on that machine as well as the daemon itself.

CFLT/.CFLT on CFLT02
Area: Disk$CFLT:[Test_Trig.Daemon]
Daemon startup: START_CFLT_DAEMON
- CFLT/COMPONENT.CFLT -- interface between the CFLT Run Control program and the main Zeus/CDAQ run control. MONITOR_COMPONENT.APPL
- CFLT/INFOSERVER.CFLT -- provides real-time information on the status of the CFLT Run Control and related parameters in machine independent network format. See Disk$CFLT:[Test_Trig.InfoServer]CFLTRun.h and CFLTPar.h for the information provided. MONITOR_INFOSERVER.APPL
- CFLT/RSUM_FILE_SERVER.CFLT -- provides run summaries to the main Zeus/CDAQ run summary collator at the end of run time. MONITOR_RSUM_FILE_SERVER.APPL
- CFLT/REMOTE_SERVER.CFLT -- Remote communications server. MONITOR_REMOTE_SERVER.APPL
- CFLT/MONITOR.CFLT -- Monitors CFLT processes and sends message to experts (DISK$ONLINE:[CFLT]CFLT_MONITOR.DIS) when applications crash and restart or are simply missing. MONITOR_MONITOR.APPL
- CFLT/WWW.CFLT -- The CFLT Hardware machine Web server. MONITOR_WWW.APPL
CFLT/.CFLT_1 on zaxp10.desy.de
Area: /usr/users/cflt/daemon
Daemon startup: start_cflt_daemon
- CFLT/SIMCFLT_EVENT.CFLT_1 -- Flink pipe event server for simCFLT. This process requests event samples from the Flink server on zaxp11 and feeds them to a pipe read by the simCFLT eaze job. monitor_simcflt_event.appl
- CFLT/SIMCFLT_RUN.CFLT_1 -- simCFLT executable eaze-type job. This program reads in event samples from the Flink pipe and runs ZgAna and compares the expected CFLT results with those from the hardware. It produces histograms that are mapped to the shared memory "SIMC". monitor_simcflt_run.appl
CFLTP/.CFLTP on ZWS016
Area: Disk$Online:[CFLTP.Daemon]
Daemon startup: START_CFLTP_DAEMON
- CFLTP/CFLTPDQM_HIST.CFLTP -- program to fill online hbook histograms with data from the CFLTP OS9; creates the global section CFLTPDQM MONITOR_CFLTPDQM_HIST.APPL
- CFLTP/CFLTPDQM_MONITOR.CFLTP -- listens for commands from the CFLT Run Control: when to write the global section for physics runs to a file; and when to reset the CFLTPDQM histograms MONITOR_CFLTPDQM_MONITOR.APPL

* NB: On the cflt OS9, the ZMP Daemon and ZHP server are not currently fully debugged by the CDAQ group. Permanent installation pending as of 10-Oct-1997.

Hints on summoning and ridding Daemons

Never directly kill the Daemon-controlled processes via a system or shell commands, since the Daemon will simply restart them. Use the Daemon client commands to start and stop the application processes instead. The syntax of these commands looks like:

zmp_daemon_client -dZEUS_APPL_CONTROL -tTarget "-cCommand Instance"

The daemon program will send these commands for you. For the CFLT Daemons, possible Target values are CFLT, CFLT_1, CFLT_2, or CFLT_3. This specifies the ZMP Daemon running on a particular node. The possible Command values are "OPEN" (start application) or "CLOSE" (stop application) which act on the application processes specified by the Instance. The value of Instance depends on the Daemon; for example, the CFLT_3 Daemon can accept values "CFLT_CAL_SERVER" or "CFLTP_LOADER". Another useful Command value is "SYMBS" which will dump the state of all applications under the Daemon control (no Instance value should be specified in this case).

In general, the ZMP Daemon process(es) should only be started at node boot time and never killed. However, if additions or deletions to the applications are required, you may stop and restart the ZMP Daemons. However, be sure to never start two Daemons at the same time, or there will be hell to pay!

Hint: People often confuse the ZMP Daemon program and the Daemon Children application processes. The ZMP Daemon controls the child processes. The ZMP Daemon runs all the time; the Daemon Children are started and stopped only by the ZMP Daemon. Component experts start and stop controlled applications (Daemon Children) by sending commands to the ZMP Daemon using the ZMP communications software. After receiving a command, the ZMP Daemon handles the process control of the Daemon Child

Last updated 2000 09

T. Wildschek W. Badgett