DevOps
Linux
Bootstrapping S3/CloudFront with LetsEncrypt
Let's assume that you want to do the following:
- Host the contents of your S3 bucket via YOUR.DOMAIN.COM
- Use CloudFront
- Use a LetsEncrypt cert
"What's the problem?", you may ask. There are plenty of tutorials for this stuff. Not exactly. A CloudFront Distribution will not let you add a CNAME until you have an SSL cert, but you can't use certbot to auto-provision an SSL cert until you are hosting from your domain.
Solution
The easiest solution is to initially generate your SSL cert manually. You can then use something like certbot-s3front to auto-renew.
Details
Continue reading "Bootstrapping S3/CloudFront with LetsEncrypt"
Hardware Hacks
Adventures in Modifying a UPS for external DC power and LiFePO4 batteries»
I have an ancient APC Smart-UPS 1400 RMNET. It's a very nice UPS, but I have frequent multi-hour power outages and battery life becomes a problem. I have these issues:
Short battery runtime , especially as batteries age
Lead-acid batteries require frequent replacement and quickly lose capacity (and there are 4 of them)
UPS will not accept 110v from a cheap generator (mine is a ...
DevOps
Linux
PowerShell on Linux doesn't find modules when run through Puppet»
I'm running PowerShell on Linux for the sake of using PowerCLI . An interesting thing happens: when pwsh is run interactively, in a terminal, the following works fine when PowerCLI is already installed:
pwsh -c 'Get-InstalledModule VMware.PowerCLI'
When puppet runs it - it doesn't find the module:
Get-Package: ...
DevOps
Java
Gradle Toolchains Support - different JVMs for compile and test»
I'm testing a product that needs to be compiled with JDK 8 but tested (sometimes) on JDK 11. This is now possible to do with maven surefire (although that took some effort). With gradle, I was doing it as follows, which is terrible, even if the path comes from configuration:
// The old way: test { executable = '/some/hardcoded/path/to/java' } ...
DevOps
Linux
Puppet recipe for setting up autossh via systemd»
I've always set up autossh in /etc/rc.local , but with CentOS 8 that doesn't work well (things start too early, etc). Luckily, there is a nicer way using systemd templates. Essentially, all you have to do is create one symlink and one config file per instance of autossh.
Example:
Make a config file
/etc/autossh/mything.conf:
OPTIONS=-N -M 20000 ...
DevOps
Using puppet to set Windows Computer Description» My company's security department decided to assign Antivirus exclusion policies based on the value of the windows computer description. That means that I need to set computer descriptions ( net config server /srvcomment:"new description" ) to the same value on a whole bunch of windows machines. Doing that by hand is unappealing, and I already have puppet, so here is a simple solution: ...
Low Tech Hacks
Replacing Dishwasher Circulation Pump Bearings without buying a whole new unit»
I have a DW80j3020us/AA Samsung dishwasher. It has been producing a loud noise for some time, and the noise kept getting worse. It was a matter of time before it either seized or melted the motor. The reason I know that the problem is with the circulation pump is that the noise is only audible while it's washing (circulating), not while draining or filling. Clearly the problem could be ...
Android
Android doing Optimizing app 1 of 1 on every boot» The message appears for a good 15 minutes every time my phone boots up. I followed the usual suggestions (wipe cache partition), and that didn't help
Figuring out what app is causing this issue is the hard part. I did it with logcat (I happened to have the Android Studio installed, so logcat is a tab, and it displays the log automatically as the plugged-in phone is booting). You ...
DevOps
Disabling Windows Recycle Bin with Puppet on all versions of Windows» And when I say "All versions of Windows" I mean that I tested it on Server 2008, 2012 and 2016.
This was oddly hard to figure out, and most tutorials either apply to only one version of windows or to outdated tools. The best way to do this that I found was using Local Group Policy. Now, how to automate this? The puppet local group policy module didn't work at all when I tried it ...
DevOps
Jenkins Pipeline: parallel and waitUntil, waiting until the other branch finishes» Let's say that for the sake of speed, you are running two slow things in parallel, but you want one to wait for the other.
parallel one: { node { sh "sleep 15" } } , two: { node { //slow part: sh "sleep ...
Code and Hacks
Customizing Windows 7 keyboard and mouse to act like Linux»
After using only Linux for nearly 20 years, I'm being forced to use a Windows machine for work. To make matters worse, I'm really (really) used to Enlightenment shortcuts, yet I use XFCE (Xubuntu). So, I'd like to have a seamless experience if I can help it. This is a log of my experimentation.
Note that I am not talking about a skin - I don't care that much about the looks, and ...
Linux
OCR on a large PDF using tesseract and pdftk»
This turned out to be harder than I thought. I found a large (50MB) PDF with about 50 pages, and none of the tesseract GUI's seemed to be able to handle it without crashing. The solution is to convert the PDF to TIFF so that command-line tesseract could handle it directly, but now ImageMagick couldn't handle that conversion as it was running out of memory (even with the limit settings). ...
DevOps
Java
Linux
Running Jenkins Swarm client as a service via Upstart»
This turned out to be fairly simple, with only one gotcha: do not follow the how-to's out there that tell you to use expect fork . The process doesn't technically fork. When I had that setting enabled, upstart commands would hang under very specific but repeatable conditions (if the process was killed externally).
So, here is my upstart conf file:
