I needed to add more storage space on the /home directory of a Xen guest running on a RHEL5 system. I investigated extending its LUN on the NetApp Filer and then tried running pvresize to see if the Xen guest would recognise the new size. No luck. In the end, i created another iSCSI LUN, mapped it to the Xen host, configured the Xen guest to see the new LUN and let LVM know it had another physical disk to play with. This is how i did it.

iSCSI was officially ratified by the IETF on 11th of February 2003 and is a transport layer protocol allowing devices to access remote block devices over TCP/IP using the SCSI protocol. Think ISCSI over the network and you have iSCSI.

I will break this tutorial down into 3 parts.

1. Configure the RHEL5 iSCSI client
2. Create an iSCSI LUN on the NetApp filer
3. Build the Xen guest

Solaris
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Nagios is a stable and well regarded open source monitoring suite. NRPE is a Nagios plugin that allows a remote Nagios monitoring server to log into a server and execute a Nagios check. The Nagios check will then return information that is relevant to the service the Nagios monitoring server is monitoring.

To install NRPE on Solaris, i use the blastware.org package. The blastwave.org nrpe package also depends on the nagiosp package which contains the standard nagios plugins. If you havent setup your Solaris box with blastwave.org, instruction are included below.

Copy the blastwave.org package pkg_get.pkg to /tmp/ . You can do this from another server using scp.

# pkgadd -d /tmp/pkg_get.pkg
# /opt/csw/bin/pkg-get -i nrpe
# wget -P /tmp/ http://www.terdmonk.com/files/solaris/nagios/nrpe_smf.zip
# cd /tmp
# unzip nrpe_smf.zip
# mv nrpe/manifest/nagios-nrpe.xml /var/svc/manifest/network
# mv nrpe/method/nagios-nrpe /lib/svc/method/nagios-nrpe
# svccfg import /var/svc/manifest/network/nagios-nrpe.xml
# svcadm disable nrpe
# svcadm enable nrpe

To check if nrpe is working you should see the following

# svcs | grep nrpe
online         May_29   svc:/network/nagios/nrpe:default
# netstat -a | grep 5666
      *.5666               *.*                0      0 49152      0 LISTEN

If svcs doesnt show the service as online, you can check the SMF log file /var/svc/log/network-nagios-nrpe\:default.log.

If things still arent working, execute /lib/svc/method/nagios-nrpe manually with some bourne debugging. This will show you what the nagios-nrpe script is trying to do.

# sh -x /lib/svc/method/nagios-nrpe

Running any kind of business should involve invoicing to customers. Invoicing software comes at a cost and when you're building a company, its a cost you want to keep to a minimal.

I recently came across freshbooks.com whilst sifting through forum posts and freshmeat.net searches.

Within 4 minutes i was setup with a fully fledged invoicing system that also did project management, support tickets and document sharing with customers. And at what cost? If you have less than 3 active clients (which i do), you can use freshbooks.com for free.

After punching in some services and products that i offer, and some clients details i was able to send an invoice via email with the option to send via snail mail aswell.

Previously, ive used gnucash and opencrm. Both took more than a hour to setup and both had a steep learning curve. I needed something i could setup with minimal fuss, minimal infrastructure and minimal cost.

Im planning to use freshbooks.com alot more in the near future as i start to transfer my projects, tasks, contacts and documents that i build whilst i do my own startup.