Ghetto Xen Status Report

Pointlessly long script to give a report on total/available memory and a list of domU’s, their memory allocation, and number of vcpus on a Xen server.

It provides output similar to the following:

Status report as of: 2010-02-19 09:00:01

dom0 Information:
------------------------------------------------------------------------------

host                   lolhost.irtehrox.com
total_memory           65535
free_memory            9276

Running domU's:
------------------------------------------------------------------------------

NAME:                  MEMORY:   VCPU:
20000-web002              2048       1
20001-web001             12288       4
20001-web002             12288       4
50005-db002               2048       1
50005-web002              4096       1
60015-dev001               256       1
60015-web004              4096       1
80123-web005              8192       1
80123-web006              8192       1

While you certainly could glean this information by looking at the list of systems you should be keeping, or even logging into the server itself, who has time for that? :p

The good stuff:

#!/usr/bin/perl

# Configuration -------------------------------------------------------------
# Domain to send e-mail from; for the actual user, we use our hostname
my $SENDER = "somedomain.foo";

# Address to e-mail report to
my $RECEIVER = 'user@somehost.foo';
# ---------------------------------------------------------------------------

# Global Variables
my $hostname = "unknown";
my $email_body = "";
my $stamp = "unknown";
my $hr = "------------------------------------------------------------------------------";

# Part 1: Intial setup; grab our time, hostname, etc.
open(HOSTNAME, "/bin/hostname |");
while()
{
        # Get rid of the break
        chomp($_);

        # Kill anything after a proper hostname; this may need to be commented out
        # or modified depending on your needs
        $_ =~ s/\..*//g;

        $hostname = $_;
}
close(HOSTNAME);
$stamp = qx(date +"%Y-%m-%d %H:%M:%S");
chomp($stamp);
$email_body = $email_body . "Status report as of: $stamp\n";

# Part 2: Grab key Xen info for the dom0
my (@info_holder);
$email_body = $email_body . "\n\ndom0 Information:\n$hr\n\n";
open(XM, "/usr/sbin/xm info |");
while()
{
        # Get rid of the break
        chomp($_);

        # Selective acquisition of data
        if(($_ =~ /^host/) || ($_ =~ /^total_memory/) || ($_ =~ /^free_memory/))
        {
                # Quick regexp to ensure the line can be split easily
                $_ =~ s/\s+/ /g;

                # Eliminate the colon
                $_ =~ s/: //g;

                # Split our line
                @info_holder = split(/ /, $_);

                # Attach line to e-mail
                $email_body = $email_body . sprintf("%-20s   %s", $info_holder[0],
$info_holder[1]) . "\n";
        }
}
close(XM);

# Part 3: Grab list of running domU's
my (@domu_holder, @domu_out, $i);
$i = 0;
open(XM, "/usr/sbin/xm list |");
while()
{
        # Get rid of the break
        chomp($_);

        # Kill the header and Dom-0 lines
        if(($_ =~ /^Name /) || ($_ =~ /^Domain-0 /))
        {
                next;
        }

        # Quick regexp to ensure the line can be split easily.
        $_ =~ s/\s+/ /g;

        # Insert into our holding array
        $domu_holder[$i] = $_;

        # Increment our counter
        $i++;
}
close XM;
@domu_holder = sort(@domu_holder);
$email_body = $email_body . "\n\nRunning domU's:\n$hr\n\nNAME:                  MEMORY:   VCPU:\n";
foreach(@domu_holder)
{
        # Split the line so we can extract name, vcpu, mem
        @domu_out = split(' ', $_);

        # Format it up!
        $email_body = $email_body . sprintf("%-20s   %7s   %5s", $domu_out[0], $domu_out[2],
$domu_out[3]) . "\n";
}

# Finally, send the e-mail
open(SENDMAIL, "|/usr/sbin/sendmail -t");
print SENDMAIL "To: $RECEIVER\n";
print SENDMAIL "From: $hostname\@$SENDER\n";
print SENDMAIL "Subject: Xen Status Report For $stamp\n";
print SENDMAIL $email_body . "\n";
close(SENDMAIL);

No doubt there’s an easier way to go about doing this, but I have a talent for simplifying the complex and complicating the obvious. Should’ve been a politician.