Jeremy Wadhams's questions

I'm using the script utility to record terminal sessions, and using logrotate (with copytruncate, script ignores HUP and keeps writing to the rotated file otherwise) to periodically upload chunks of what's happened so far to another server. This works great for the the actual screen contents.

Today I'm trying to also capture timing information, which script emits to STDERR. So my new script config looks like

script -faqt session.record 2> session.timing

The problem is that when I use logrotate on the timing data (session.timing) the backfilled file begins with a large number of null bytes in the output, which causes scriptreplay to hork when it reads the reconstructed file back in.

Is there a known problem (and hopefully workaround) using logrotate with the copytruncate option on STDERR redirected into a file?

When configuring HA Proxy, how do you decide what values to assign to the timeouts? I've read a half dozen samples in various blogs, and everyone uses different timeouts and no one discusses why.

HAProxy seems specifically worried about client, connect, and server, which HAPRoxy throws a warning about if you leave completely unset:

While not properly invalid, you will certainly encounter various problems
with such a configuration. To fix this, please ensure that all following
timeouts are set to a non-zero value: 'client', 'connect', 'server'.

The documentation is unhelpful in this regard: it suggests "slightly above multiples of 3 seconds" but not why you'd choose a multiple of 1 vs 100 or 42.

The RPM I'm using (Amazon Linux repository) sets these defaults:

timeout connect         10s
timeout client          1m
timeout server          1m

Two of which are exact multiples of 3 seconds, violating the only official advice I've seen.

If you don't have specific tuning advice, maybe an easier question is: what should I expect to go wrong with really short or really long timeouts?

Obviously, Amazon EC2 servers are still running on physical hardware and therefore can have catastrophic failures. And architecturally, I should be building an app that scales horizontally and works around those failures.

How can I simulate an EC2 instance suddenly breaking down? This should have characteristics of a real equipment failure:

• Processes don't terminate cleanly.
• Data in memory is not given a chance to write to disk.
• Files (e.g., on EBS volumes) are not cleanly closed.
• Open sockets don't FIN, they just hang.

RFC 2181 liberalized the acceptable characters in DNS names back in 1997. But people still seem to be skittish about using underscore in hostnames. (For example, GoDaddy won't sell a second level domain with an underscore, like "this_bites.com")

In a few minutes of testing, a third-level hostname containing underscores "just works" on everything in my office. (e.g., that_guy.example.com, my DNS host is Amazon Route 53)

It "just works" on Win XP and Win 7, Mac OSX 10.7, IE8 and 9, modern Firefox, Safari, and Chrome.

Where could I expect it to not work?

(Why do I care? I'm assigning virtual machines to students, and I want to use the user ID they've chosen in the hostname to remind them that their actions on box are directly attributable to them. Unfortunately, a large percentage of pre-existing student user IDs contain underscores.)

Is it possible to add bcrypt support for system accounts (e.g., in /etc/shadow) in Amazon Linux? (Which is in turn binary compatible with RHEL5 and CentOS 5)

This only looks like a duplicate of this question. The body and accepted answer for that question are Debian specific and don't appear to help me.

Is it possible to make a Cisco router (2821 and 2811 model today, possibly any member of the 28xx or 38xx family in the future) use a config file on the compact flash card or a generic USB thumb drive as the startup-config (ignoring whatever is in NVRAM)?

I'd like to use this as a mechanism to get configuration information onto a router straight out of the box, without having to serial into the console port at all.

The config will be pretty vanilla stuff, IP and speed assignment for F0/0, T1 controller configuration -- nothing I would expect to require the "secure eToken" product.

My company just deployed a dozen Windows XP touch screens in conference rooms to control video conferencing systems. We're using all-in-one PCs with no keyboard or mouse attached, so the only way to wake from screensaver is to touch the screen, which is of course interpreted as a click.

The problem we're having is that the click is passed through to the top app -- our video conf control system -- causing the user to take some action (like hangup) that they didn't intend.

We do need to have a screensaver, the PCs are turned on 24x7, and the control app is visually very static. We expect a simple bouncing image screensaver to significantly lengthen the productive life of the system.

Is this something we can tweak? The screensaver content is a single bouncing image, so I'd be open to replacing the screensaver, or tweaking the registry, or (best) pushing the change via Active Directory (all the affected systems are already grouped into a specific OU).

I'm testing Snow Leopard for our IT team in preparation for it's actual launch. I'm currently running seed 10A394, which comes with Java JDK 1.6.

I found one Java desktop application that no longer runs under Snow Leopard, the app won't even start. The vendor is recommending that I downgrade to JDK 1.5.

The problem is that every Java for Mac package that I've been able to find first checks that it's about to be installed on the version of Mac OS that Apple had in mind when the package was created. This page is a good example, there are two different packages but each explicitly checks for MacOS 10.4 or 10.5 before installing, so neither works on Snow Leopard.

Once I get it installed, I know how to change the order so that the lower version is preferred -- I just can't find any packages that will install.