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Netgear ReadyNAS & DynDNS Replacement

With the demise of free DNS services from companies such as DynDNS, I was left with no free method of reliably accessing my Netgear ReadyNAS via the internet.

Before these free services closed down, my ReadyNAS was configured to automatically update it’s IP address to the DynDNS service website, which allowed me to use a DynDNS provided host address (e.g. mydevice.dyndns.org) to access the ReadyNAS no matter what it’s IP address was changed to by my home ISP provider.

When the free service eventually stopped, I decided that I didn’t want to pay for such a small service offering, so I wrote a small script to perform the same sort of service.
The script simply checks my current ISP assigned IP address and compares it to the previous run of the script. If the IP address has changed between checked, the script sends an email to my email account, which I can then use to access the device by directly entering the IP address into my web browser.

It’s not neat, but it works.
Here’s how I did it.

What you’ll need:
– Root access to your ReadyNAS (you need the SSH addon installed).
– Configure email alerting on your ReadyNAS (do this in FrontView by giving it access to your email provider e.g. smtp.gmail.com).

Step 1 – Create the script.

As the root user connected to your ReadyNAS via SSH, use vi to create a small script in the home directory of the root user:

# cd $HOME

# vi check_ip_address
#!/bin/bash
#——————————————————–
#  Get IP address and mail it to us.
#  Place this script in $HOME/root
#  Call it from crontab.
#
#——————————————————– user=”ReadyNAS”
email_from=$(grep ‘^from’ /etc/msmtprc | cut -f2 -d’ ‘)
email_addr=`grep email /etc/frontview/alert.conf | awk -F ‘!!’ ‘{ print $2 }’ | awk -F ‘,’ ‘{ print $1 ” ” $2 ” ” $3 }’`
subject=”IP Address Changed” newfile=/tmp/myip.html
oldfile=/tmp/myip.old
# Call a generic site to get our IP.
wget –no-cookies –no-cache –user-agent=”Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2049.0 Safari/537.36″ –no-verbose –output-document=/tmp/myip.html https://www.askapache.com/online-tools/whoami/
# Read output.
myipnew=`awk -F “tt>” ‘{ if($2 ~/./){ sub(/<//,””,$2); print $2} }’ $newfile`
myipold=`cat $oldfile 2>&1`
if [ “$myipnew” != “$myipold” ]; then
  # IP is different to last, so save it and mail it.
  echo “$myipnew” > $oldfile
  mesg=”New IP Address: $myipnew”   headers=”From: $email_fromnTo: $email_addrn”
  full_content=”${headers}Subject: ${subject}n${content}nn$mesg”
  echo -e “$full_content” | /usr/sbin/sendmail -B8BITMIME -f $email_from $email_addr &> /dev/null
  echo “RC: $?”
fi 

Set permissions on the script:

# chmod 750 check_ip_address

Step 2 – Schedule the Script.

Add the script to a cron schedule:

# export EDITOR=vi

# crontab -e
30 09 * * * /root/check_ip_address
30 14 * * * /root/check_ip_address

The above schedules the script to run at 09:30am every day, and again at 14:30.
That’s it!

Power Notes Searcher Updated to v1.1

The Chromium project has recently (May 2014) fixed a bug in the Chrome web browser which means that users of my Power Notes Searcher Google Chrome extension may have seen an issue with the table ordering in the SAP Notes history table.

I have now made a slight correction to the extension and v1.1 is now available for update/install in the Google Chrome Extensions Web Store (or from the link on my initial blog post here).

If you haven’t already installed my extension, give it a go. You don’t know what you’re missing!

Power Notes Searcher – Find SAP Notes Smarter

After working as a BASIS guy for many years, I’ve come to the conclusion that SAP don’t want to provide an easy experience when analysing SAP notes.
Compared to Oracle’s MYOS site, SAP have a long way to go.
For SAP notes, it takes time find them, you go round in circles and you forget what you’ve read and what you haven’t.
It costs me a lot of time on my projects, so I thought there must be a better way.

I decided to invest some time. I taught myself how to write a Google Chrome Extension and created the FREE Power Notes Searcher extension for Google Chrome.

It’s just gone live on the Google Chrome App Store today!
Very exciting!

I hope it makes you more productive with your work. It definitely has made me more productive and I can produce better documentation, quicker! This is great news for my current and potential clients.

UPDATE:
August 2014 has seen v1.1 released, with a small fix to the table ordering in the notes history.

VMWare ESXi 4.1 Test Rig – UPDATE

This is an update to my previous post here.

The VMware install onto the HP XW6200 hardware was a snip:
VMware ESXi 4.1 Update 1 Install Guide
VMware ESXi 4.1 Update 1 Release Notes

I decided to use a spare 8GB USB pen (check requirements in the installation guide relating to swap space) to install the VMware hypervisor on. This enables me to use the entire size of the internal SATA disks as VMware datastores for hosting guest operating systems. It also means I can create a backup copy of the USB pen when trying out a VMware upgrade.

Total time to install:
– Download boot CD ISO = 10mins.
– Burn boot CD from ISO = 5 mins.
– Install from CD to USB pen = 10 mins.
– Download vSphere Client = 5 mins.
TOTAL = 30mins.

Once installed, I then downloaded the VMware standalone converter to my laptop.
I had two VirtualBox guest machines on my laptop, so I used the VMware converter to simply pull them off (there is no pun here!) onto the VMware virtual infrastructure.
My LAN is not the fastest so total time to v2v conversion was about 10 hours to do both guest VMs.

The next problem was the Oracle Linux 6.1 install.
This seems to come in two separate parts; the boot ISO and the main DVD ISO.
Downloading the main DVD ISO took about 3 hours over my simple ADSL connection.

Once downloaded, my problems started.
I attached the Oracle Linux 6.1 boot ISO to the virtual CDROM of a new 64bit virtual machine and click “Power On”.
Then, bam! No longmode enabled:

What!
Well, it turns out that the history of the Intel XEON processor is a rather tarnished story of rivalry between Intel and AMD.
Although the XEON processor I have *is* 64bit capable, and does support EM64t with Hyperthreading and all that, it just doesn’t have the VT (virtualization) capability.
The spec of the XEON processors in the HP XW6200 workstations can be seen on the Intel page here https://ark.intel.com/products/27086/64-bit-Intel-Xeon-Processor-3_40E-GHz-2M-Cache-800-MHz-FSB.

Looking at the Intel page is even more confusing, since it states it doesn’t have Hyperthreading, but I have just enabled it in the BIOS. Does it? Doesn’t it? Arghh!

In summary, you’re better off getting any one of the Core2Duo processors as these will undoubtedly support EM64t and VT.
Only problem is, most don’t support 8GB of RAM due to the system board limitations (more than likely a soft limitation). Oh dear indeed.

So my story doesn’t end there, I’m now in the process of downloading and installing 32bit Oracle Linux 6.1. Not quite what I wanted, but it will suffice because I have limited memory so will not be needing the use of 64bit memory addressing capabilities – yet.
My other task is to download the 32bit version of the Oracle 11g XE. But wait, Oracle only provide a Linux version of the 11g XE in 64bit mode. Scuppered! I’ll have to use the 32bit version for Windows only.

As you can see, we are in this awkward transition period where software is both 32bit and 64bit but hardware is 32bit or 64bit or 64bit with flags.
We are trying our best to virtualise, but for the small guy it’s an expensive project.
You either buy a server or you buy the latest and greatest desktops that support more than 4GB of RAM.
It’s a very tricky thing to get right.
For me, it’s a case of trying to keep skills current. I think I can afford £166 for now, then re-invest another £166 at a later stage to make the jump to a “proper” 64bit (with VT) capable system.

One other thing, once the free version of VMware ESXi expires (you get 60-days free use of all the features), you’ll need to spend some time faffing with the license to register it (downgrade to free only features) so you can continue to use it. I did this up-front so I don’t have a situation where I can’t use the VMs because I forgot the expiry date.
See instructions here: https://planetmediocrity.com/2010/09/vmware-vsphere-evaluation-downgrade/.

VMWare ESXi 4.1 Test Rig – Up up and away!

This weekend I will be focussing my attention on getting my new (old) HP XW6200 workstation transformed into a VMWare ESXi 4.1 test rig.
Bought on eBay for £166.00.

I did take a brief look at the Oracle VM 2.2 offering, but it required about twice the amount of storage space to install it compared to the ~200MB required by VMWare ESXi 4.1 and it didn’t have the nice GUI for simplicity or the excellent VMWare converter for transfering my existing VirtualBox guest VMs to the virtual infrastructure.

The plan is to install VMWare onto a USB pen device, then use the 500GB SATA disk and 1TB SATA disk as virtual disk storage where I can host all manner of Virtual Servers.
I’m planning to use OpenFiler inside a virtual appliance, to provide a shared chunk of disk via iSCSI so that I can get ASM working in a cluster.
I’m hoping to get an Oracle Unbreakable Linux server running and download the beta Oracle 11gR2 XE RDBMS.
For those of you in the know, Oracle don’t officially support VMWare (I wonder why…) but since I’m not running a production database, this is not a problem. I know for sure that it *will* work fine.

The XW6200 machine spec:
2 x Intel Xeon 3.4gGhz with HT and EM64t.
256MB graphics card.
4GB RAM (for the moment, but will support 8GB via 4x2GB DIMMS).
500GB SATA
1TB SATA
CDROM
Floppy (really!)
USB sockets galore.

It’s a little power sucker, but it supports wake-on-lan so I can have it shutdown until required.