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04/21/08

Permalink 09:27:45 am, by Stephen Email , 155 words   English (US)
Categories: Personal Musings

Mahalo Vlog Idol

Link: http://www.mahalo.com/mahalo_idol

So this is a totally silly blog post, and not something I’d normally care about… but…

Mahalo is a human-powered search engine that works to create a *useful* index of relevant web information. Not necessarily important web information, but definitely relevant information. They also have a daily video podcast, Mahalo Daily, about casually interesting, and sometimes techy topics. They used to have Veronica Belmont as the host/interviewer, but she moved on to other things, and Mahalo decided to have a contest to select a new host.

For some reason (probably because it was snowing in Seattle in April), I watched some of the live stream of the host selection contest, and one young lady, Lisa Brewster, seemed to stand out from the rest of the Hollywood actresses that showed up. She seemed like the ideal combination of cute, techy, geeky that would be great for a video podcast like Mahalo Daily.

Good luck Lisa.

Lisa Brewster

01/18/08

02/18/07

Permalink 11:42:23 pm, by Stephen Email , 349 words   English (US)
Categories: Open Source, Sysadmin Tricks

DIY Dynamic DNS

Since I control a server with a real public IP address, as well as having various computers that are assigned dynamic IP addresses, I wondered if I could setup my own dynamic DNS system similar to dyndns.org. I found an open source project called GNUdip that fit the bill.

The docs on GNUDIP were adequate for the installation, but I ran into a few things I had to do differently. The basic steps are as follows:

  1. Pick a server with a real public IP
  2. Disable or set to non-enforcing your SELinux (setenforce 0)
  3. Configure the BIND DNS server for basic operation. I did some special setup here that warrants noting. I setup my existing milton.com domain file hosted on ISOMEDIA's name servers to reference an external DNS server for ddns.milton.com. Here is the relevant section of my milton.com zone file:

    $ORIGIN milton.com.
    ns1.ddns IN A 207.115.64.96
    ddns IN NS ns1.ddns

    This causes any lookups to *.ddns.milton.com to be forwarded to the DNS server at 207.115.64.96 (my personal server).
  4. Configure Apache web server for basic operation (Note: in CentOS apache and bind don't run under the nobody user, they run under apache and named respectively.)
  5. Configure MySQL database server for basic ops
  6. Install GNUDIP tables into MysQL
  7. Configure BIND for secure DNS updates
  8. Edit the gnudip.conf file to reflect your setup
  9. I decided to use web updates exclusively, so I skipped the XINETD setup steps in the GNUDIP docs

So far I have left the public registration methods turned off, so only pre-configured users can update their DNS in my system. If you want me to add you to the system, drop me an email and I can set you up an account such that yourname.ddns.milton.com will always point at your dynamic DNS computer.

PS. If you're wondering why I didn't just use DYNDNS or some other publicly available FREE dns service, you aren't alone. I thought about it, but I prefer to control my own services, not rely on some other company to track my IP address registrations.

12/22/06

Permalink 03:59:40 pm, by Stephen Email , 99 words   English (US)
Categories: Hardware

Drupal installation on milton.com

Link: http://www.milton.com

So, just to ensure that 2006 doesn't slip by without an article...

I installed the latest release candidate for the Drupal content management system onto my personal domain, milton.com. It installed easily, and seems to work very nicely. I transitioned all of my old content (not much) into it in an evening. I haven't bothered to setup the Gallery2 modules for embedding my photo gallery, but I may tackle that eventually.

There are a LOT of modules available for this system, so much experimentation to come.

Cheers.

Update: Embedding the Gallery2 modules was also accomplished, and works very nicely.

12/17/05

Permalink 02:08:09 pm, by Stephen Email , 1235 words   English (US)
Categories: Open Source, Sysadmin Tricks

Load Balanced LVS-NAT FTP Server w/ Keepalived+iptables+proftpd HOWTO

I was recently tasked with setting up a 5 server cluster for load balanced FTP and static web content serving. I found enough information on the Linux Virtual Server Project and Keepalived to get the standard failover and web protocol load balancing working well. However, when it comes to FTP and NAT, many of the online docs make comments like "Multi-port protocols are too hard!", and "I can get active ftp to work, can I somehow disable passive since it doesn't work?", and "this example config bypasses the virtual server for FTP, and isn't load balanced". In fact I found so many docs on FTP related issues, where the author only presented 10% of the solution, that putting all of them together into a working solution was dificult. So here I will attempt to gather together the complete working configuration that I finally stumbled upon.

The software packages that I used to complete this solution are:

  • Red Hat Enterprise Linux 4.2 WS (should work identically with Centos 4.2)
  • IPVSADM version 1.24 works properly with the current Red Hat kernel version 2.6.9-22.0.1.EL.
  • Netfilter - iptables - default versions that came with RHEL 4.2
  • ProFTPd version 1.2.10
  • arpreset 0.2 - a package I wrote for resetting single MAC addresses on a Cisco router; helps with making the failover fast
  • check_ftpget.pl - written by Jeremy Hanmer for the excellent Nagios system monitoring project.

My cluster consists of 2 load balancers (setup for active-passive failover), and 3 web/ftp servers. Here is the diagram of how they are networked together:

           VIP: (.10)     VIP: [.1]
              +-+             +-+
              |X|             |X|
              |X|-----LB1-----|X|-----Web1
              |X|  (.2)  [.2] |X|      [.11]
              |X|             |X|
   Router-----|X|             |X|-----Web2
      (.1)    |X|             |X|      [.12]
              |X|             |X|
              |X|-----LB2-----|X|-----Web3
              |X|  (.3)  [.3] |X|      [.13]
              +-+             +-+
           switch             switch

 (192.168.1.0/24)             [192.168.2.0/24]

LB1    = LVS-NAT Master Load Balancer
LB2    = LVS-NAT Backup Load Balancer
Web1-3 = Web & FTP Servers

Note:  (.1) = 192.168.1.1
       [.3] = 192.168.2.3

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The goal for this blog is to have a place to document for posterity all the funky software, hardware, and sysadmin tricks I think up, look up, or mess up. It will also serve as a jumping off point for my own software projects, as well as my test bed for all the crazy open source projects that catch my eye on the net.


Posterity is me. I have a bad memory, and I have forgotten more of these types of tricks than I will ever remember to write down. I've got to start somewhere.

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