Patch 4/4 This patch adds the ability to notify ldirectord that a system should be forced down for maintenance (or other reasons) even though the service check passes.
This patch introduces a new option "maintenancedir" which allows the administrator to specify a directory in which ldirectord will check for the existence of files indicating if the realserver should be forcibly set down (irrespective of and bypassing the normal service check). If a site is using a management tool such as cfengine or Puppet that watches and manages the ldirectord configuration file it may not be possible or practical to modify the configuration file to remove a realserver or weight it to 0 during maintenance. This mechanism provides a quick and simple way to signal ldirectord that a real server should be set down without having to modify any configuration files. Thanks, Sean
# HG changeset patch # User Sean E. Millichamp <[email protected]> # Date 1242335637 14400 # Node ID f63eaa5274c6c6036fe090ddc6181672efdece46 # Parent c5f037878efa07946d2b8772db41901ea62c3442 Add the ability to notify ldirectord that a system should be forced down for maintenance. This patch introduces a new option "maintenancedir" which allows the administrator to specify a directory in which ldirectord will check for the existence of files indicating if the realserver should be forcibly set down (irrespective of and bypassing the normal service check). Signed-Off-By: Sean E. Millichamp <[email protected]> diff -r c5f037878efa -r f63eaa5274c6 ldirectord/ldirectord.in --- a/ldirectord/ldirectord.in Mon May 11 16:43:14 2009 -0400 +++ b/ldirectord/ldirectord.in Thu May 14 17:13:57 2009 -0400 @@ -349,6 +349,48 @@ Default: I<yes> +B<maintenancedir = >I<directoryname> + +If this option is set ldirectord will look for a special file in the specified +directory and, if found, force the status of the real server identified by the +file to down, skipping the normal health check. This would be useful if you +wish to force servers down for maintenance without having to modify the actual +ldirectord configuration file. + +For example, given a realserver with IP 172.16.1.2, service on port 4444, and +a resolvable reverse DNS entry pointing to "realserver2.example.com" ldirectord +will check for the existance of the following files: + +=over + +=item 172.16.1.2:4444 + +=item 172.16.1.2 + +=item realserver2.example.com:4444 + +=item realserver2.example.com + +=item realserver2:4444 + +=item realserver2 + +=back + +If any one of those files is found then ldirectord will immediately force the +status of the server to down as if the check had failed. + +Note: Since it checks for the IP/hostname without the port this means you can +decide to place an entire realserver into maintenance across a large number of +virtual service pools with a single file (if you were going to reboot the server, +for instance) or include the port number and put just a particular service into +maintenance. + +This option is not valid in a virtual server section. + +Default: disabled + + =head2 Section virtual The following commands must follow a B<virtual> entry and must be indented @@ -696,6 +738,7 @@ $EMAILALERTFROM $SMTP $CLEANSTOP + $MAINTDIR $CALLBACK $CFGNAME @@ -1188,6 +1231,7 @@ $FALLBACKCOMMAND = undef; $FORKING = "no"; $LDIRLOG = "/var/log/ldirectord.log"; + $MAINTDIR = undef; $NEGOTIATETIMEOUT = -1; $QUIESCENT = "no"; $SUPERVISED = "no"; @@ -1606,6 +1650,12 @@ $1 =~ /(^([0-9A-Za-z._+-]+))/ or &config_error($line, "invalid SMTP server address"); $SMTP = $1; + } elsif ($linedata =~ /^maintenancedir\s*=\s*(.*)/) { + $1 =~ /(.+)/ or &config_error($line, + "maintenance directory not specified"); + $MAINTDIR = $1; + -d $MAINTDIR or &config_warn($line, + "maintenance directory does not exist"); } else { if ($linedata =~ /^timeout\s*=\s*(.*)/) { &config_error($line, @@ -2540,10 +2590,14 @@ my $v = shift; my $r = shift; + my $real_id = get_real_id_str($r, $v); my $virtual_id = get_virtual_id_str($v); - if ($$v{checktype} eq "negotiate" || $$r{num_connects}>=$$v{num_connects}) { + if (_check_real_for_maintenance($r)) { + service_set($v, $r, "down", {do_log => 1, force => 1}, "Server in maintenance"); + return; + } elsif ($$v{checktype} eq "negotiate" || $$r{num_connects}>=$$v{num_connects}) { &ld_debug(2, "Checking negotiate: real server=$real_id (virtual=$virtual_id)"); if (grep $$v{service} eq $_, ("http", "https", "http_proxy")) { $$r{num_connects} = 0 if (check_http($v, $r) == $SERVICE_UP); @@ -2613,6 +2667,40 @@ } } +sub _check_real_for_maintenance +{ + my $r = shift; + + return undef if(!$MAINTDIR); + + my $servername = ld_gethostbyaddr($$r{server}); + + # Extract just the first component of the full name so we can match short or FQDN names + $servername =~ /^([a-z][a-z0-9\-]+)\./; + my $servershortname = $1; + + if (-e "$MAINTDIR/$$r{server}:$$r{port}") { + &ld_debug(2, "Server maintenance: Found file $$r{server}:$$r{port}"); + return 1; + } elsif (-e "$MAINTDIR/$$r{server}") { + &ld_debug(2, "Server maintenance: Found file $$r{server}"); + return 1; + } elsif ($servername && -e "$MAINTDIR/$servername:$$r{port}") { + &ld_debug(2, "Server maintenance: Found file $servername:$$r{port}"); + return 1; + } elsif ($servername && -e "$MAINTDIR/$servername") { + &ld_debug(2, "Server maintenance: Found file $servername"); + return 1; + } elsif ($servershortname && -e "$MAINTDIR/$servershortname:$$r{port}") { + &ld_debug(2, "Server maintenance: Found file $servershortname:$$r{port}"); + return 1; + } elsif ($servershortname && -e "$MAINTDIR/$servershortname") { + &ld_debug(2, "Server maintenance: Found file $servershortname"); + return 1; + } + return undef; +} + sub check_http { use LWP::UserAgent; @@ -4854,6 +4942,26 @@ return $ret[0]; } +# ld_gethostbyaddr +# Wrapper to gethostbyaddr. Look up the hostname from an IP address. +# If no reverse DNS record is found, return undef +# pre: ip: IP address of host to lookup +# post: gethostbyaddr is called to find a hostname for IP $ip +# return: hostname +# undef on error + +sub ld_gethostbyaddr +{ + my ($ip)=(@_); + + my @host = getaddrinfo($ip,0); + if (!defined($host[3])) { + return undef; + } + my @ret = getnameinfo($host[3], NI_NAMEREQD); + return undef unless(scalar(@ret) == 2); + return $ret[0]; +} # ld_getservbyname # Wraper for getservbyname. Look up the port for a service name
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