(The latest version of this document is at http://www.milkywaygalaxy.freeservers.com. You may want to check there for changes).
Processes are the "heart" of the Linux/Unix processes. It is very important to monitor the application processes to ensure 100% availability and reliability of the computer system. For example, processes of databases, web-server etc.. need to be up and running 24 hours a day and 365 days a year. Use the tools described in this document to the monitor important application processes.
See also the following related topics on Linux/Unix processes.
Use the program procautostart (say "Prok-Auto-Start" or Process AutoStart) to monitor and automatically re-start any Unix/Linux process if they die. This tiny program is very powerful and is comparable to big commercial products which costs about $80,000US. Procautostart can be used for controlling following applications:
The program listing is given in following sections in this document.
procautostart -n < delay_seconds > -c "< command_line >" nohup &
This starts the unix process procautostart and also command_line process. The procautostart process will re-start command_line process if it dies. The -n option is the time delay in seconds before procautostart checks the running process started by command_line. It is advisable to start the procautostart as background process with no-hangup using "nohup &". See 'man nohup'.
The procautostart is written in "C" so that it is very fast and efficient, since the program is called every n seconds. Amount of resources consumed by procautostart is very minute and is negligible since the program size is small and is highly optimized with -o3 compiler option.
For example -
procautostart -n 12 -c "monitor_test -d $HOME -a dummy_arg " nohup &
The program will output log files in 'mon' sub-directory which has datetime stamp of when the processes died and re-started. These files gives info on how often the processes are dying.
You can also use micro-seconds option '-m' or nano-seconds option '-o', edit the source code file procautostart.cpp and uncomment appropriate lines.
Download the latest version of the program from http://www.milkywaygalaxy.freeservers.com, go here and click on 'Source code for Process Monitor HOWTO'.
// From your browser save this file as text-file named as 'debug.cpp'.
#ifdef DEBUG_PRT
#include "debug.h"
// Variable value[] can be char, string, int, unsigned long, float, etc...
void local_dbg(char name[], char value[], char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %s\n", fname, lineno, name, value ); }
void local_dbg(char name[], int value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %d\n", fname, lineno, name, value ); }
void local_dbg(char name[], unsigned int value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %d\n", fname, lineno, name, value ); }
void local_dbg(char name[], long value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %ld\n", fname, lineno, name, value ); }
void local_dbg(char name[], unsigned long value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %ld\n", fname, lineno, name, value ); }
void local_dbg(char name[], short value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %d\n", fname, lineno, name, value ); }
void local_dbg(char name[], unsigned short value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %d\n", fname, lineno, name, value ); }
void local_dbg(char name[], float value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %f\n", fname, lineno, name, value ); }
void local_dbg(char name[], double value, char fname[], int lineno, bool logfile) {
printf("\nDebug %s Line: %d %s is = %f\n", fname, lineno, name, value ); }
// You add many more here - value can be a class, ENUM, datetime, etc...
#endif // DEBUG_PRT
// From your browser save this file as text-file named as 'debug.h'.
#ifdef DEBUG_PRT #include <stdio.h> //#include <strings.h> //#include <assert.h> // assert() macro which is also used for debugging // Debugging code // Use debug2_ to output result to a log file #define debug_(NM, VL) (void) ( local_dbg(NM, VL, __FILE__, __LINE__) ) #define debug2_(NM, VL, LOG_FILE) (void) ( local_dbg(NM, VL, __FILE__, __LINE__, LOG_FILE) ) void local_dbg(char name[], char value[], char fname[], int lineno, bool logfile= false); void local_dbg(char name[], int value, char fname[], int lineno, bool logfile= false); void local_dbg(char name[], unsigned long value, char fname[], int lineno, bool logfile= false); void local_dbg(char name[], float value, char fname[], int lineno, bool logfile= false); #else #define debug_(NM, VL) ((void) 0) #define debug2_(NM, VL, LOG_FILE) ((void) 0) #endif // DEBUG_PRT
# From your browser save this file as text-file named as 'Makefile'.
#//*****************************************************************
#// Copyright policy is GNU/GPL and it is requested that
#// you include author's name and email on all copies
#// Author : Al Dev Email: alavoor[AT]yahoo.com
#//*****************************************************************
.SUFFIXES: .pc .cpp .c .o
HOSTFLAG=-DLinux
#HOSTFLAG=-DSunOS
CC=gcc
CXX=g++
MAKEMAKE=mm
#LIBRARY=libString.a
DEST=/home/myname/lib
# Note: You should set only ONE value of MYCFLAGS below, that is only
# one line is uncommented and others are commented.
# Use options -Wall (all warning msgs) -O3 (optimization)
MYCFLAGS=-DDEBUG_PRT -g3 -Wall
#MYCFLAGS=-O3 -Wall
#PURIFY=purify -best-effort
SRCS=procautostart.cpp debug.cpp
#HDR=my_malloc.h String.h StringTokenizer.h File.h debug.h string_multi.h
#LIBOBJS=my_malloc.o String.o StringTokenizer.o File.o debug.o
OBJS=procautostart.o debug.o
EXE=procautostart
# For generating makefile dependencies..
SHELL=/bin/sh
CPPFLAGS=$(MYCFLAGS) $(OS_DEFINES)
CFLAGS=$(MYCFLAGS) $(OS_DEFINES)
#
# If the libString.a is in the current
# directory then use -L. (dash L dot)
MYLIBDIR=-L$(MY_DIR)/libmy -L.
ALLLDFLAGS= $(LDFLAGS) $(MYLIBDIR)
COMMONLIBS=-lstdc++ -lm
MYLIBS=-lString
LIBS=$(COMMONLIBS) $(MYLIBS)
all: $(LIBRARY) $(EXE)
$(MAKEMAKE):
@rm -f $(MAKEMAKE)
$(PURIFY) $(CXX) -M $(INCLUDE) $(CPPFLAGS) *.cpp > $(MAKEMAKE)
$(EXE): $(OBJS) $(LIBRARY)
@echo "Creating a executable "
$(PURIFY) $(CC) -o $(EXE) $(OBJS) $(ALLLDFLAGS) $(LIBS)
#$(LIBRARY): $(LIBOBJS)
# @echo "\n***********************************************"
# @echo " Loading $(LIBRARY) ... to $(DEST)"
# @echo "***********************************************"
# @ar cru $(LIBRARY) $(LIBOBJS)
# @echo "\n "
.cpp.o: $(SRCS) $(HDR)
# @echo "Creating a object files from " $*.cpp " files "
$(PURIFY) $(CXX) -c $(INCLUDE) $(HOSTFLAG) $(CPPFLAGS) $*.cpp
.c.o: $(SRCS) $(HDR)
# @echo "Creating a object files from " $*.c " files "
$(PURIFY) $(CC) -c $(INCLUDE) $(HOSTFLAG) $(CFLAGS) $*.c
clean:
rm -f *.o *.log *~ *.log.old *.pid core err a.out lib*.a afiedt.buf *.class tags
rm -f $(EXE)
rm -f $(MAKEMAKE)
ln -s ../cpphowto/libString.a .
#%.d: %.c
# @echo "Generating the dependency file *.d from *.c"
# $(SHELL) -ec '$(CC) -M $(CPPFLAGS) $< | sed '\''s/$*.o/& $@/g'\'' > $@'
#%.d: %.cpp
# @echo "Generating the dependency file *.d from *.cpp"
# $(SHELL) -ec '$(CC) -M $(CPPFLAGS) $< | sed '\''s/$*.o/& $@/g'\'' > $@'
# Must include all the c flags for -M option
#$(MAKEMAKE):
# @echo "Generating the dependency file *.d from *.cpp"
# $(CXX) -M $(INCLUDE) $(CPPFLAGS) *.cpp > $(MAKEMAKE)
include $(MAKEMAKE)
#include $(SRCS:.cpp=.d)
#include $(SRCS:.c=.d)
From your browser save this file as text-file named as 'monitor_test'.
Use this program for testing the 'procautostart' program. For example -
procautostart -n 12 -c "monitor_test -d $HOME -a dummy_arg " nohup &
#!/bin/ksh
# Program to test the procautostart
echo "Started the monitor_test ...."
date > monitor_test.log
while :
do
date >> monitor_test.log
sleep 2
done
bash$ tail -f monitor_test.log
bash$ ps -ef | grep monitor_test
See the PID of monitor_test and kill it..
bash$ kill -9 < PID of monitor_test >
The init command is a cool tool to do simple process monitoring. Add :respawn: entry to your /etc/inittab, if you need procees to be respawned. See the online manual page by typing 'man init' at bash prompt.
On linux systems you can find the following packages. If it is not in the main cdrom than you must check in the contrib cdrom :
$ top
$ ktop
$ gtop
Visit the web site of daemontools at http://www.pobox.com/~djb/daemontools.html
To install the daemontools RPM, do -
# rpm -i /mnt/cdrom/daemontools*.html
# man supervise
supervise monitors a service. It starts the service and restarts the service if it dies. The companion svc program stops, pauses, or restarts the service on sysadmin request. The svstat program prints a one-line status report. See man page by 'man supervise'
svc - control a supervised service.
svc changes the status of a supervise-monitored service. dir is the same directory used for supervise. You can list several dirs. svc will change the status of each service in turn.
svstat - print the status of a supervised service.
svstat prints the status of a supervise-monitored service. dir is the same directory used for supervise. You can list several dirs. svstat will print the status of each service in turn.
cyclog writes a log to disk. It automatically synchronizes the log every 100KB (by default) to guarantee data integrity after a crash. It automatically rotates the log to keep it below 1MB (by default). If the disk fills up, cyclog pauses and then tries again, without losing any data. See man page by 'man cyclog'
accustamp puts a precise timestamp on each line of input. The timestamp is a numeric TAI timestamp with microsecond precision. The companion tailocal program converts TAI timestamps to local time. See 'man accustamp'
usually watches a log for lines that do not match specified patterns, copying those lines to stderr. The companion errorsto program redirects stderr to a file. See 'man usually'
setuser runs a program under a user's uid and gid. Unlike su, setuser does not gain privileges; it does not check passwords, and it cannot be run except by root. See 'man setuser'
There are commercial monitoring tools available. Check out -
Linux goodies main site is at http://www.milkywaygalaxy.freeservers.com Mirror sites are at - angelfire, geocities, virtualave, Fortunecity, Freewebsites, Tripod, 101xs, 50megs,
This document is published in 14 different formats namely - DVI, Postscript, Latex, Adobe Acrobat PDF, LyX, GNU-info, HTML, RTF(Rich Text Format), Plain-text, Unix man pages, single HTML file, SGML (Linuxdoc format), SGML (Docbook format), MS WinHelp format.
This howto document is located at -
You can also find this document at the following mirrors sites -
Single HTML file can be created with command (see man sgml2html) - sgml2html -split 0 xxxxhowto.sgml
PDF file can be generated from postscript file using either acrobat distill or Ghostscript. And postscript file is generated from DVI which in turn is generated from LaTex file. You can download distill software from http://www.adobe.com. Given below is a sample session:
bash$ man sgml2latex bash$ sgml2latex filename.sgml bash$ man dvips bash$ dvips -o filename.ps filename.dvi bash$ distill filename.ps bash$ man ghostscript bash$ man ps2pdf bash$ ps2pdf input.ps output.pdf bash$ acroread output.pdf &
This document is written in linuxdoc SGML format. The Docbook SGML format supercedes the linuxdoc format and has lot more features than linuxdoc. The linuxdoc is very simple and is easy to use. To convert linuxdoc SGML file to Docbook SGML use the program ld2db.sh and some perl scripts. The ld2db output is not 100% clean and you need to use the clean_ld2db.pl perl script. You may need to manually correct few lines in the document.
bash$ ld2db.sh file-linuxdoc.sgml db.sgml
bash$ cleanup.pl db.sgml > db_clean.sgml
bash$ gvim db_clean.sgml
bash$ docbook2html db.sgml
You can convert the SGML howto document to Microsoft Windows Help file, first convert the sgml to html using:
bash$ sgml2html xxxxhowto.sgml (to generate html file)
bash$ sgml2html -split 0 xxxxhowto.sgml (to generate a single page html file)
In order to view the document in dvi format, use the xdvi program. The xdvi program is located in tetex-xdvi*.rpm package in Redhat Linux which can be located through ControlPanel | Applications | Publishing | TeX menu buttons. To read dvi document give the command -
xdvi -geometry 80x90 howto.dvi
man xdvi
You can read postscript file using the program 'gv' (ghostview) or 'ghostscript'. The ghostscript program is in ghostscript*.rpm package and gv program is in gv*.rpm package in Redhat Linux which can be located through ControlPanel | Applications | Graphics menu buttons. The gv program is much more user friendly than ghostscript. Also ghostscript and gv are available on other platforms like OS/2, Windows 95 and NT, you view this document even on those platforms.
To read postscript document give the command -
gv howto.ps
ghostscript howto.ps
You can read HTML format document using Netscape Navigator, Microsoft Internet explorer, Redhat Baron Web browser or any of the 10 other web browsers.
You can read the latex, LyX output using LyX a X-Windows front end to latex.
Copyright policy is GNU/GPL as per LDP (Linux Documentation project). LDP is a GNU/GPL project. Additional restrictions are - you must retain the author's name, email address and this copyright notice on all the copies. If you make any changes or additions to this document than you should intimate all the authors of this document.