Where Do I Put My Crontabs?

There's another good discussion forming around where to put your crontabs on the SAGE mailing list.

On linux based systems, there are typically 4 places to stick your crontabs:

1. Where ever crontab -e puts them on your system (per user crons)
2. /etc/crontab
3. /etc/cron.daily, /etc/cron.hourly, /etc/cron.weekly and /etc/cron.monthly
4. /etc/cron.d

My opinion is that crons should go into /etc/cron.d only. They should ideally be grouped into one file per application, or some other logical breakout (database maintenance, health checks, email crons, etc).

Putting them into /etc/cron.d makes it easy to revision control the files and keep track of changes. It's also handy for package management -- you can build a custom RPM or DEB of your app and have it drop any required crontabs into /etc/cron.d.

Crons should never run as human user account. When they are configured this way, they tend to break if someone leaves or an account is shut down for other reasons. Depending on what the cron needs access to, it should run as nobody, apache, and in special cases, root. It's easy to configure which user a cron runs as in these files since each entry in the file requires you to specify which user to run as.

Of course, if your cron doesn't support /etc/cron.d, ignore everything I said :)

LongJump DaaS

LongJump's Database as a Service was featured on TechCrunch today. It appears to be a competitor to SimpleDB:

LongJump’s DaaS provides a complete environment for hosting a database that’s highly secure and web-enabled while simultaneously cutting the costs and easing the hassles for entrepreneurs and developers who would otherwise have to purchase a database server, provision it, address data access and availability issues, manage backup and replication issues, and tackle security and data protection.

They mention that they use Java on MySQL, but it does not appear that they actually expose MySQL API's. According to their sales copy, it's only REST 

My quick scan of their product pages indicate that you need to sign up for LongJump to get access. They charge by the user account as opposed to usage. I don't know if it counts as utility computing then :)

I'll sign up for an account in the next couple of weeks, but on first glance this seems to be targeted at smaller businesses and databases.

Network Monitoring: Auto Discovery vs. Configuration Management

There is some discussion on the SAGE-members list regarding network monitoring solutions. The first post was about Zenoss vs. Nagios. I haven't been involved in the conversation, I've only been lurking. 

I have maintained a few Nagios installs, usually configured via fruity. Before my Nagios/Cacti days, I ran a couple of large mon installs. 

I've been unsuccessful and unsatisfied with Zenoss in the past. I felt it wasn't monitoring what's important to me (mostly raid arrays). I couldn't figure out how to add custom monitoring in. I also had a brief stint with Hyperic, but the free version didn't give me access to the features I wanted.

An interesting comment was added today. Neil Watson said:

I am planning to move to a system that I can configure with my configuration management system instead of auto discovery (probably Nagios as I have used it before).

I've long thought that the division between people who want to use auto discovery and manual configuration has to do with the number of systems you need to maintain. I've been on the manual config side as I've never had more than 100 systems to monitor. I typically write macros to quickly add systems of similar types.

When I was at Scale5x last spring, the OpenNMS people were talking about how many tens of thousands of systems they could monitor with one station and how quickly they could get it up and running. I thought it was cool, but it didn't matter all that much to me.

To me, it's more important to use source control systems to maintain configuration management than using auto discovery. I also want to specify what I monitor -- I'll hand pick what's important for my environment. I also want to know how and why it changes.

I can think of two things that would make me switch camps:

1. I'm in a position where I monitor 200+ machines
2. A monitoring system lets your write customer monitors in perl/ruby/python and the interface includes the ability to add auto discovery code to your monitor

SuperBlade Servers

I came across a press release for a new quad core SuperMicro SuperBlade today. I'm not currently in the market for one of these, but I was shopping around for blade servers about a year ago.

I wonder how long Supermicro will support this platform? I also wonder if they offer support contracts and SLA's for parts. You're putting a lot of eggs into one basket with these chassis'.

Back then, I found that the market was pretty bleak -- the products from Dell and IBM were silly. You might as well buy 1U servers -- they were more powerful and the density was around 1.1 servers/u (of course, you get management and power savings). The IBM machines didn't have hot swap drive bays. The Dell blades were 7U's tall.

HP's c-Class chassis was the exception back then. It was well thought out and had a good density. Since then, they've even come out with a half sized chassis. Their blades were their 1U and 2U servers crammed into a blade and included hot swap drive bays. You could even install a storage module for additional drive attachments.

When I was doing the price comparision, the break even point seemed to be around a half filled chassis -- if you were buying 8 blades, it was cheaper than the equivalent 8 stand alone machines. That included networking modules in the chassis, but no networking for the stand alone machines.

Last year, when I was meeting with the HP reps, they said the c-class chassis was their blade platform for years to come (I'm thinking at least 5 years).

I've been using Supermicro servers for ages. They were always cheaper than the big names and they ran reliably. Recently, I 'grew up' to using HP and Dell servers. I've learned that there are some advantages to buying name brand servers instead. They tend to work better as a unit -- they are well thought out and easy to service.

The biggest issue I ran into with Supermicro was getting replacement parts (like power supplies) for 2 year old Supermicro machines. We've had to throw out a few perfectly fine machines due to lack of parts. With a support contract on a Dell or HP machine, you'll get the part you need.

I won't be in the market for a blade server for a while now, but t least there is another product on the market for comparison when it is time.

List-Unsubscribe

Since I'm leaving my current gig, I'm starting to unsubscribe from all the various mailing lists I'm a part of. This will should make the person who inherits my email address life easier.

I decided awhile ago to only pick up RSS feeds in Google Reader and to no longer subscribe to email lists. Email is for personal communication only. There are a few exceptions (like SAGE). Otherwise, the stuff I'm still subscribed to is left over from before I started using Google Reader.

Most of the mailing lists I subscribe to have List-Unsubscribe headers. That means I only have to view source on mailing list messages to find out how to unsubscribe.

I wish more mail clients supported using these headers. Hotmail sort of has it (but I never really got it working as a sender, so I don't trust it. I also don't use hotmail). You'd think it would be relatively easy to add to Gmail or Mail.app. I'm not the only one to consider it, either.

Google even recommends adding the header:

Provide a 'List-Unsubscribe' header which points to a web form where the user can unsubscribe easily from future mailings (Note: This is not a substitute method for unsubscribing).

I guess I'll be copying and pasting for a bit.

The Snow and a New Gig

It's snowing again.

I live on top of Burnaby Mountain near SFU, so it's somewhat expected. Since xmas day, it's snowed every day up here, which is unusual. It mostly rained yesterday, so a lot of the old snow is gone. It didn't snow this much all last winter. It looks like it's starting to stick, too.

At least I don't have to be anywhere today. I'm just hanging around watching sports. Canada is beating Sweden 1-0 in the world juniors. I may watch the Pats/Giants game tonight and there's also a pay per view Canucks game too.

I start a new job on January 14th. It's a super secret startup I've been helping out with for a bit. I'm going to get to work more with EC2 -- we're using it to get off the ground. The are lots of interested things to tie together with this project and I'm really excited about officially joining the team.

I gave my notice a week before xmas. It's kind of weird, I had been there for 8 years -- most of my career. When the news broke, everyone was very supportive, which is nice.

I will be working from home -- we'll be a 'virtual office' for a while. With my luck, it'll snow every day until I start working from home.

Futureshop Returns :(

We got 3 duplicate DVD's for xmas this year. Yesterday morning I tried to return them to Futureshop for store credit. I stood in line for about 45 minutes (and I got there early! The line got longer behind me).

They were gifts and I didn't have any receipts for them. Apparently they have a new policy that says they won't let me exchange items without receipts.

This is frustrating since I don't have receipts for any of it and probably won't be able to get them. I've had brutal customer service run-ins with Futureshop before and I already try to not shop there. Now I'm going to go out of my way to not shop there. 

If your in the lower mainland, I recommend A&B Sound. They have given me excellent customer service in the past and help out with pricing on bigger purchases. Plus they staff are far more human and friendly.