Understanding the Problem

One of the reasons a lot of us work in this industry is because we like to solve problems. We sure aren't in it for the money and fame ;). But how often do you see things suggested or even implemented that indicate a lack of understanding of the real problem?

For example, take the new scalability limits in vSphere 4.1. You can have up to 10,000 VM's managed by a single vCenter - WOW! By why do people actually ask for this? I highly doubt the people who asked for such scalability have licensing concerns - they're likely on a licensing tier that doesn't cost them anymore if they have 1 or 100 vCenter servers. Similarly, removing the need to deploy more hardware is probably a minimal concern - I'm sure a lot of those same people don't even run vCenter on physical hardware anymore. I'm willing to bet the number one reason people asked for higher limits in vCenter was operationally / support driven. But what problem does a single massive vCenter actually address, and what problems does it introduce?

Having a single vCenter means you have a single place to go for provisioning, inventory and monitoring. And that's good, because you don't have to think about it when you need to do one of those things, right? But should you really be hitting vCenter directly for any of those things? I would say not. Your provisioning process should be automated, using some kind of placement engine to determine which vCenter / vDC / Cluster / Datastore / vNetwork to put that next VM on. Your inventory data should be in a CMDB. You should be using some kind of aggregator or at the very least push notifications for monitoring (as opposed to a human "poll").

The problems of a single massive vCenter are obvious - a huge single point of failure, a beefy database, and a nightmare if you ever need to troll through some logs.

So while increasing the scalability of vCenter was the easiest thing VMware could do for customers, it's not really the best thing that customers can do for themselves. Give me multiple small vCenters and decoupled operational tools any day!

Install Postgres 8.4 on a RHEL 5.5 Derivative

Continuing with the series of 'basics' type posts, I'll cover getting Postgres up and running on Scientific Linux. A little something on the motivation for these posts... it's not because I've found something unique or amazing, it's more a reminder for myself on how to do some things. Which allows me to replace all this info in my memory with a simple pointer to the info :). The other motivation is to consolidate information... I ran into a few self-inflicted issues when doing this first time around, and found there were many guides out there for specific pieces but not an overall one that covered everything I wanted to do. So read on if you're interested!

Not Just Another Fucking 2011 Prediction Post

In fact, it's not a prediction post at all - it's just a list of things I would like to see happen or at least start happening this year. I'm not making any guesses as to whether they will or not, you can decide for yourselves what the likelihood of each is.

Adding Disks via LVM

In my last post, I mentioned that I like to use a 4GB disk for my root volume on any Linux VM's... this is mainly for local / dev environments, where you want to cram as many VM's as possible into a small space. But sometimes you need more space, in which case you can add another disk. This isn't as straight forward with lvm as it is without, so here's a nice easy step by step to help you get there after you have added a new disk to the VM. In this case, we are adding a new 2GB disk that will be configured as a new logical volume (you could of course just add to an existing volume if you wanted). We'll then format it with ext3 and mount it at /usr/local/pgsql/data.

Minimal RHEL 5.5 / CentOS 5.5 Install

After messing around with Ubuntu for a while, I decided it would be a little more portable for me to use a Red Hat based distro as my primary Linux environment. My distro of choice is actually Scientific Linux, which is developed / maintained by CERN. Why not CentOS? Frankly, Scientific Linux doesn't have any of the bullshit that CentOS does, and is for all intents and purposes identical.

Oddly enough, there is no "JeOS" option for RHEL based distro's like there is for Ubuntu. Amazon recently launched their own RHEL derivative which I thought might give me some clues as to how minimal a RHEL based distro could be, however a quick yum list installed proved it to be far from minimal - disk is cheaper than the combination of network and CPU it seems, so they cram many development packages into the base image (OpenJDK, Lua, Perl, Python, Ruby, X etc). Which is not really a huge deal to be honest, but I like to keep things as small as possible without getting ridiculous.

I'm Baaaaaack!

Heheh. Well after a few years of dedicated hosting, it was clear that I didn't need it. So here I am back at Blogger, hopefully to stay this time :)

New vinternals Site, Burning Feed...

I really need to bite the bullet on this one and move to my new wordpress based site. In the next few hours I will revert the current site to it's default vinternals.blogspot.com address, so the RSS feeds should still work. Then later this evening I'll point the vinternals.com domain at the new site. Finally, in the next day or 2 I'll burn the feeds from this site. If you haven't seen anything from me by next Sunday, either it's all gone horribly wrong or you need to update your RSS bookmark.

Hmmm, it seems putting the word burn all over the place has resulted in ads for "sexy singles" to temporarily appear on the site. Will have to use that word more often :D