Julian Dunn’s Journal

I’ve started investigating higher-order system configuration management tools, in particular, Puppet, in order to help manage CBC’s web infrastructure. About two years ago, the only player in this space was cfengine, which at the time struck me as quite functional, but also quite arcane. Puppet seems to be much easier to learn. But I’ve come up against a fundamental problem that I’m hoping more experienced Puppet users can help me with. How does one force synchronous updates to Puppet clients? In this entry, I’ll explain my use case, and hopefully get some answers as to whether Puppet is the right tool for the job.
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A while ago I wrote a post about how the Windows Media video experience is sub-optimal on non-Windows computers — in particular, Macintoshes — and why I think this will trigger a run towards Flash on-demand and eventually Flash live. Here’s a concrete example: over the last six months to a year, and perhaps longer, we’ve been dealing with a steady stream of user complaints that the nightly newscast of CBC’s The National (insert promotional tagline about “Canada’s most trusted news source, hosted by newly-announced Order of Canada member Peter Mansbridge”) is frequently “out of date”. While I haven’t totally nailed down why this might be the case, I do note that most complainants seem to be using Quicktime to play back the stream, with Flip4Mac (ugh) as the translation layer. I believe that with so many moving parts, something is inevitably going to go wrong.
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Today I sent another SATA hard drive back to Seagate because it failed. You might recall that I have had a bad track record with SATA drives: since purchasing this PC about two years ago, I’d gone through about three Western Digital SATA drives (all replaced under warranty due to failure) until I finally got fed up about six months ago and bought a pair of Seagate Barracuda 250 GB drives. One of them failed after three months, and the other died just this past weekend. Fortunately, my PC is RAID-1 protected (and I have all the data backed up on DLT) - but seriously, why are SATA drives so prone to failure?
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In previous entries here I have described my unhappiness with the Highpoint series of RAID controllers. In particular I owned the 1740 4-port SATA RAID controller, but dis-satisfaction with the frequency of driver updates finally caused me to dump the 1740 for another controller. (Note that even though Fedora 9 is the current release, Highpoint has still not updated their drivers beyond Fedora 7, which is almost EOL.)
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I’m taking a long-awaited vacation next week, in part to attend my friend Kristin’s wedding down in New Jersey, but also for the Streaming Media East conference in Manhattan. My work these days requires a great deal of knowledge about video (and audio) delivery workflows for online media, and I can see many aspects of our operation ramping up in near term. Flash-based players like the Maven Networks front-end are already in use, and I can see live Flash being only six months off. It seems like Flash is suddenly on everyone’s tongue, and at least at CBC, Windows Media, while still our standard, is no longer the market darling that it once was.
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I decided I’d rebuild my Linksys NSLU2-based PBX tonight, since SlugOS/BE 4.x had been released back in December and I wasn’t getting new versions of Asterisk pushed through the ipkg channel. Since I’ve done it before, I figured it would only take about an hour, and I was right (okay, it took ten minutes longer than I predicted, but close enough.)
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A few years ago, when I was still in charge of the Toronto Community Co-Location Project (a project that I’m pretty sure is defunct by now), I was approached by a fellow named Da Shi, who was just starting a company called 3z Canada. He provided some competitive rates for co-location, but we ultimately sublet space from Chris Kirby.
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Recently at work, we tried to implement Xen on Intel Xeon, running a 64-bit dom0/domU. I have to say that this failed horribly, so I’m writing this post to warn others off it. My colleague Gabriel worked hard to migrate everything back to a 32-bit environment, so kudos to him.

The specific symptoms we experienced while running 64-bit Xen is that the domU’s would crash and reboot randomly under (or after) high load. One of our domU’s is a development server, which also runs a CruiseControl, a continuous integration system. This means that every minute, CruiseControl wakes up, does a cvs update to see if there are any changes, and then recompiles the project(s) if needed. Periodically we started to see error messages like

Bad pte = 32971e067, process = cvs, vm_flags = 100077, vaddr = b7f34000
[] vm_normal_page+0xb7/0xd3
[] unmap_vmas+0×3d1/0×761
[] unmap_region+0×8a/0xf0
[] do_munmap+0×148/0×19b
[] sys_munmap+0×33/0×41
[] syscall_call+0×7/0xb
=======================


After a few of these, domU would reboot. It seems like others are having the same problem on 64-bit Xen. This user was running CentOS 5.1, which is basically what we’re running (we have the real deal Red Hat Enterprise LInux 5.1).

As I said, migrating the domU back to a 32-bit dom0 seemed to fix this, so let this be a fair warning to others thinking of running a 64-bit dom0.

It’s that time of year again when I start to think about what computer upgrades I might want to do. I’ve had some annoying things happen with my desktop PC recently and have considered either replacing it entirely, or implementing some much-needed upgrades.
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Some of you are aware that I’m into vintage computers. Sadly, my basement cannot hold all the computers I wish I could actually have - and some of them are forever going to be too big to fit in any man’s house (not to mention “make it past a man’s significant other“).

But why would one actually need a VAX when, these days, one can emulate one on a Linux PC using SIMH? Not only can one emulate a VAX (take your pick: MicroVAX or VAX 11/780) but also a PDP-11, Data General Nova, some ancient Honeywell mainframes I’ve never heard of, or a bunch of other old mainframes or minicomputers.

I have a special nostalgia for the VAX, since I accessed my first real e-mail account at the National Capital Free-Net via a VAX in my dad’s office. On the anniversary of my Dad’s retirement, I’ve decided I’m going to try to get a VAX running in emulation under SIMH - running OpenVMS, no less. Do I know anything about running OpenVMS? Nope, I do not - but I’m going to find out. Yes, I know it’s a nearly obsolete operating system, and DCL is not the most intuitive. But hopefully it should prove to be a little bit amusing at least - wish me luck!

(On a completely unrelated note: People are still writing in to comment on the blog post where I got yelled at by Drew of Toothpaste For Dinner for offering an RSS feed. Haha! I’ve moved onto reading xkcd these days … that fellow seems far less uptight, and his comics are more reliably funny. And yes, xkcd has an RSS feed, if you had to ask.)