Configuring Debian to Patch Itself

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After a couple of years in the IT infrastructure world, you’ll be faced with the greatest task of all, updating servers every month or so. This has always been the most brain dead task imaginable, but now with virtualization, we also have 10 times more servers to update. And almost every single week there’s another critical bug in some core service that has to be patched in panic.

So, instead of doing all that, why don’t we just do what we always do when we have a task that humans don’t like to do? We get a computer to do it for us!

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The World’s Longest Console Cable – Smartflex Router Series

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As everybody knows, console cables and their corresponding interfaces are a scourge on a network administrators existence. They are always too short, COM-ports get renumbered, Baud-rates are unknown, etc. By their very nature, you also have to be physically present in the vicinity of the box you’re trying to configure. Today we’re going to change all that, by constructing a wireless console cable adaptor with almost infinite range.

I can almost here people shouting something about SSH and Telnet to their screens, as well as something about the Airconsole. First and foremost, telnet and SSH are both wonderful, after you’ve configured the device, but for initial setup, they sadly can’t be used. Airconsole is quite nice, and I use it almost daily, but it’s useful when you want to sit somewhere comfortable when configuring a device in the same room as you, not so much when you want to be comfortable on a beach half a world away from the offending device.

This we’re going to change today, with one device, the B+B SmartFlex router.

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FreeNAS: Migrating a RAID-Z vdev to a RAID-Z2

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For the last couple of weeks, I’ve been playing around with a FreeBSD distribution that’s quite interesting, FreeNAS. FreeNAS basically turns any old box you have lying around into a NAS, though you should definitely not run it on any old box. The only problem was, I got a bit excited when setting up my system, so I configured a RAID-Z vdev for my zpool. Technically, this was not an issue at the time when I set up the pool, since I was using old leftover 160GB and 250GB drives. But after a while I replaced the 160GB drives with two 1 TB drives I had laying around. And a couple of days later, I ordered 2 4TB drives to replace the 250GB ones. And then RAID-Z started to be a problem. You see, RAID-Z suffers from the same problems as RAID5, aka. that if you set up an array with large SATA drives (1 TB or larger), and one drive fails, you’re almost guaranteed a bad day (if you’re not running enterprise grade drives, more on this later in a separate post). So before I went and installed the new drives I migrated my whole pool to a backup drive and destroyed the old vdev and pool. Here’s a short guide on how I, relatively successfully did it. Continue reading

Problems installing Windows 10 from scratch?

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I recently had to do a reinstall of Windows 10 on a 3 year old Lenovo desktop. I previously updated the machine from Windows 7 to Windows 10, and shortly thereafter the hard drive started to give intermittent issues, so I decided to upgrade the machine with a SSD and do a clean install of Windows 10 at the same time. Turns out, installing Windows 10 from scratch isn’t that easy, so here are some of the things I discovered while researching the issue.

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Setting up NTP on HP Switches – HP Networking Series Part 3

This is a short guide on how to set up NTP time synchronisation on HP Network devices. I’ll be covering SNTP settings in this guide, as well as some of the niftier things that aren’t in the manuals but still are really handy. NTP time synchronisation allows you to maintain correct time across your network, which is very important for troubleshooting when comparing logs between two switches for example.

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Using the reload command with HP Switches – HP Networking Series Part 2

When configuring network hardware over the network itself it’s very easy to issue a command that breaks the network connection to the switch, requiring you to visit the switch and connect to it with a console cable to fix the issue. This is not a big problem if the switch is just down the hall in a closet somewhere, but in today’s world a switch that you’re configuring might be hundred of miles away from where you’re sitting.

Of course this whole issue can be sidestepped by just thinking through what you’re doing before hitting the enter key, but in the real world this is not always an available luxury.

The solution to this problem is to cleverly utilize the “reload” command in combination with the “write” command.

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How to set up STP on HP Switches – HP Networking Series Part 1

Setting up Spanning Tree on HP switches is really easy, after you’ve done it a couple of times, but getting it configured can seem like a daunting task for beginners, espcially in a production network. Here are some simple steps on how to get it up and running in no time. Note that enabling STP might cause small network outages, so don’t do this in a production network if you haven’t tried it before! All commands are written within “citation”-marks, so that’s what you need to enter into the CLI on your switch. For completeness I’ve added all the commands in order at the bottom of the post, which might be handy if you’re just looking for a CLI-reference.

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Professional Rack Installation = 8 Hours of Labeling


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Originally uploaded by BlaM4c

Last week I spent close to 8 hours printing and applying labels to different cables in a packed and live rack. And it didn’t help that the rack runs our virtual servers, ie. our most mission critical servers.
The rack itself consists of 3 identical 1U servers from Dell, 2 Gigabit Dell switches trunk’d into each other running separate VLANs for iSCSI and “normal” traffic. The EqualLogic HDD-array that provides the storage for the servers runs 2 controllers, both with a connection to both switches. Then there’s 5 CAT6 cables for each server providing the iSCSI, server management, virtual server NIC etc.

All in all I think I labeled 5 cables per server (15), 3 per EqualLogic module (6), 3 iSCSI cables for some other servers and 2 trunk cables. In both ends. So if my math is correct, that amounts to 30+12+6+4= 52 labels on just network cables. Then the servers needed 2 labels each (6), the EQ-box plus labels identifying the controller modules (3), the 2 UPSs and the 2 switches. That’s 13 more labels. So all in all I did over 65 labels that day.

Now, I’m perfectly clear on why this rack needs labels just about everywhere. Imagine on cable comes loose when you’re fiddling with something. Then if that cable end is labeled with which port it goes into, then reconnecting it correctly becomes a very minor task, and can be done quite swiftly.

The problem I had with this task is that the week before, 2 technicians from Dell spent the whole week setting up the rack. It would have been a lot easier for everyone if they’d bothered labeling every cable as it went into the rack in the first place instead of me carefully tracing each and every cable in the operational rack.