Use icinga2 IDO database to figure out which is active

cron_failover.pl

@@ -0,0 +1,129 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use Config::JSON;
+use DBI;
+use File::Compare;
+use File::Copy;
+use Sys::Hostname;
+
+$| = 1;
+
+# Read config file
+my $config_file = $ARGV[0];
+
+my $config      = Config::JSON->new($config_file) or die "Can not open config file: $config_file";
+
+my $crontab       = $config->get('crontabs');
+my $sharedcrontab = $config->get('sharedcrontab');
+my $masterfile    = $config->get('masterfile');
+
+
+my $i = `hostname --fqdn`;
+chomp $i;
+my $apacheuid = 33;
+my $crongid = 107;
+
+# Connect to the dabase and see which one icinga thinks is the master
+sub get_master_from_db {
+	# Setting up for db query
+	my $database      = $config->get('db');
+	my $db_host       = $config->get('host');
+	my $db_user       = $config->get('user');
+	my $db_password   = $config->get('password');
+
+    my $connect = DBI->connect( "DBI:mysql:database=$database;host=$db_host",
+        $db_user, $db_password, { RaiseError => 1 } );
+    my $query =
+      $connect->prepare("SELECT endpoint_name FROM icinga_programstatus");
+    $query->execute();
+
+    my $active = $query->fetchrow();
+    return $active;
+}
+
+# See what the file sais about who is master
+sub get_master_from_file {
+
+    open( my $fh, '<:encoding(UTF-8)', $masterfile )
+      or die "Could not open file '$masterfile' $!";
+
+    my $master = <$fh>;
+    close($fh);
+    chomp $master;
+
+    return $master;
+
+}
+
+# update the file with current master
+sub set_master_in_file {
+    open( my $fh, '>', $masterfile )
+      or die "Could not open file '$masterfile' $!";
+    print $fh $i;
+    close $fh;
+}
+
+# See if I am master
+sub is_active {
+    my ($master) = @_;
+    my $status = 0;
+
+    if ( $i eq $master ) {
+        $status = 1;
+    }
+
+    return $status;
+}
+
+# Do the work
+sub run {
+    print "Starting run at $i.\n";
+    # See if I am active as far as Icinga is concerned
+    if (is_active(get_master_from_db)) {
+        print "Icinga sais that I am master.\n";
+        # See if I am active as far as the file thinks
+        if (is_active(get_master_from_file)) {
+            print "No failover has happened.\n";
+            # See if the crontab has changed
+            if (compare( $crontab, $sharedcrontab ) != 0) {
+                print "The cronfile has changed, copying it to the shared drive.\n";
+                # Copy the crontab to the shared file if it has changed
+                copy( $crontab, $sharedcrontab );
+                chown $apacheuid, $crongid, ($sharedcrontab);
+            }
+
+        }
+        # If this clause executes, there has been a failover
+        else {
+            print "A failover has happened.\n";
+            print "Installing cronfile from the shared drive.\n";
+            # Copy the shared crontab to my crontab and set me as active in the file
+            copy( $sharedcrontab, $crontab );
+            chown $apacheuid, $crongid, ($crontab);
+            set_master_in_file;
+        }
+
+    }
+    # If this clause executes, I am not the master
+    else {
+        print "Icinga sais I am not master.\n";
+        # Remove the cronfile
+        if( -e $crontab) {
+            print "A failover has happened.\n";
+            print "Removing crontab.\n";
+            unlink $crontab;
+        }
+    }
+}
+
+# We want to run six times in a minute
+for (my $index = 0; $index < 6; $index++) {
+    my $start = time;
+    run;
+    if ((my $remaining = 10 - (time - $start)) > 0) {
+        sleep $remaining;
+    }
+}
+exit;