Dave's Brain

Browse - computer tips - linux make sure all services are running

Date: 2011may5
OS: Linux

Q.  How can I make sure all my services are running?
I want to restart a service it crashes.

A.  I run the following script every 5 minutes and it does the trick.
Will only work on RedHat / Fedora.

cron entry:

	# minute hour mday month wday    command
	# 0-59   0-23 0-31 0-12  0-6 (0=Sun)
	#
	*/5 * * * * /usr/local/bin/service_check_all_cron

Here is /usr/local/bin/service_check_all_cron:

	#!/usr/bin/perl
	# This is intended to be run from cron
	
	use strict;
	
	sub getServices() {
		local(*FILE);
		my($line, @services, $service, $status);
	
		open(FILE, '/sbin/chkconfig --list 2>/dev/null |');
		while ($line = <FILE>) {
			chomp($line);
			if ($line =~ m/^(\w+).+5:(\w+)/) {
				$service = $1;
				$status = $2;
				if ($status eq 'on') {
					push(@services, $service);
				}
			}
		}
		close(FILE);
		return @services;
	}
	
	sub getStatus($) {
		my($service) = @_;
		local(*FILE);
		my($line, $status);
	
		# Not all services support "status"
		$status = 'unknown';
		open(FILE, "/sbin/service $service status 2>&1 |");
		while ($line = <FILE>) {
			chomp($line);
			if ($line =~ m/\sis\s+(.+)/) {
				$status = $1;
				$status =~ s/\.+//g;
			}
			elsif ($line =~ m/dead/) {
				$status = 'dead';
			}
			elsif ($line =~ m/Active:\s(.+)/) {
	                        my $active = $1;
	                        if ($active =~ m/\((.*)\)/) {
	                                $status = $1;
	                        }
	                }
		}
		close(FILE);
		return $status;
	}
	
	sub uptime() {
		local(*FILE);
		my($line);
	
		open(FILE, "uptime 2>&1 |");
		while ($line = <FILE>) {
			chomp($line);
			print "UPTIME: $line\n";
		}
		close(FILE);
	}
	
	sub restart($) {
		local(*FILE);
		my($service) = @_;
		my($line);
	
		open(FILE, "/sbin/service $service restart 2>&1 |");
		while ($line = <FILE>) {
			chomp($line);
			print "RESTART: $line\n";
		}
		close(FILE);
	}
	
	my(%g_no_restart) = 
	(
	cpuspeed => 1,
	mdmonitor => 1,
	portreserve => 1,
	ip6tables => 1,
	irqbalance => 1,
	iptables => 1,
	netfs => 1,
	mcstrans => 1,
	);
	
	sub checkServices(@) {
		my(@services) = @_;
		my($service, $status);
		my($restarted) = 0;
	
		for $service (@services) {
			if ($g_no_restart{$service}) { next; }
			$status = getStatus($service);
			## print "$service is $status\n";
			sleep(1);
			if ($status eq 'unknown') { next; }
			if (!($status eq 'running' || $status eq 'active')) {
				if ($restarted == 0) {
					uptime();
				}
	
				print "Restarting $service because it is $status\n";
				restart($service);
				$restarted++;
			}
		}
	
		## print "Restarted $restarted services\n";
	}
	
	sub main() {
		my(@s);
	
		@s = getServices();
		my $n = scalar @s;
		## print "There are $n services\n";
	
		sleep(1);
	
		checkServices(@s);
	}
	
	main();

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