The greatest challenge to any thinker is stating the problem in a way that will allow a solution

Bertrand Russell

Welcome to vBlog, a personal record of my techy tinkerings and particular ponderings.

I tend to focus on VMware virtualisation, and the interaction/automation of it using PowerCLI (VMware's PowerShell Snapin), but anything that I happen to stumble across that seems like it might be of use at a later date, may well get recorded here.

I also maintain vWiki, which was a predecessor to this blog. Wiki's are great for quickly recording snippets of info, but tend not to look that great; Blog's are better looking things, but seem to require more effort so that the posts/articles are accessible in their own right. As a result I tend to update both interchangeably as available time, and depth of thought, permit.

If you happen to find anything of use, or in need of correction please leave a comment. Knowing that my ramblings are of some use is a great reward; and similarly I'd hate to waste anybody's time by feeding them duff info.

See these pages for me info about me, and my vBlog, and below for my recent posts...

I manage a number of Vyatta routers, for which the config changes irregularly.  And whilst I do keep an offline copy of their configs, I do this in a manual fashion, which means its not done reliably, which means its not a reliable backup solution.

Hence I crafted a simple PowerShell script which takes a backup of the routers config if its changed since the last backup… Continue reading →

3 Apr 2012

VMware

5 comments

With SSH access to your ESX servers, it is relatively easy to get the driver and firmware software revision versions that are running (see further reading section at bottom of post).  Which is fine for a one-off inspection, but if you want review your entire ESX estate, this can be quite tedious.

With the wonder of PowerCLI, it is possible to gain most of this information from your vCentre, which will have sourced the information from your ESX through its hardware CIM provider.  But the quality of data returned in this manner varies, you can get…

  • No data (if you server vendor hasn’t fully implemented CIM to cover the server and peripheral devices, or you haven’t installed the CIM provider software, even if you can get data for X and Y, Z may be missing, for example HBA firmware on all HP servers I’ve had the pleasure of looking after)
  • Duplicate data (if you’ve upgraded software you can sometimes get both old and new versions reported)
  • Inconsistent data (representations vary between manufacturers/vendors, so dealing with different makes or even models from the same manufacturer is problematic)

I do all reporting through PowerShell and PowerCLI scripts, and had got fed up with having to tinker with my scripts to try and never fully trusting the data I was seeing.  But more recently I’ve been using PowerShell to act as an SSH client, so decided to take a different approach…
Continue reading →

28 Mar 2012

PowerShell

5 comments

Catchy title, eh?

I make quite extensive use of the NAT’ing functionality of Vyatta routers, and it can be quite a pain in the task to keep track of servers’ real (local) and NAT’ed (remote) IP addresses.

Therefore I have the need to collate all the address translations into a central report, in an easy (aka scripted) fashion.  There are probably other ways of achieving this, but for me its a PowerShell script that SSH’s to each Vyatta router in order to query it… Continue reading →

12 Mar 2012

VMware

(No comments)

Whilst not always recommended for production use, its certainly very common for admins to want to have SSH access enabled to all ESX’s all of the time. You don’t need it for day to day support tasks, but it can be very useful, especially when things start to go wrong.  And to my mind, the easier it is to start getting into the detail of an incident, all the better chances you have of resolving it quickly and correctly.

However, enabling SSH access causes a yellow warning on your ESX’s with is annoying, and risks clouding other more important errors you might want to take action on.

If you’re running ESX5 you may see…

  • ESXi Shell for the Host has been enabled
  • SSH for the host has been enabled

There are three ways that I’m aware of to remove the warning… Continue reading →

To my mind, the beauty of a truly powerful scripting language, is the sense that you can achieve anything that you might need to. You just need to apply yourself, and the full force of Google, and be prepared for a bit of trial and error.

The fact that PowerShell let’s you unleash the full might of the .NET army means that this is pretty much true for it. Recently I head the need to be able to interact with a number of Vyatta routers (see my SSH to Vyatta Router Using PowerShell post), in order to be able to get a load of virtual machine’s NAT’ed addresses, and found two possible solutions, one of which is fairly well documented on the Web (which I struggled to get on with), the other of which is new (in beta still at time of writing) and not particularly prevalent, but seems very flexible…. Continue reading →