A quickie today on leveraging “the cloud” for warm-ish spare servers.
I run a mix of physical and cloud based servers. The Cloud is convenence, however, in general, I prefer physical servers for lower cost (over time anyway) and greater control. Of course that means having dependency on hardware, upstream connectivity, data center power, etc.
I sometime hedge my bets by keeping a backup copy of the server in AWS.
So, first I talked my first programming experience, learning via type-in programs. Then I looked at the shotgun approach my university took. In this final post of the series, I’m going to talk about what was the most important learning experience on my path to becoming a developer.
Last time I talked about my first experience with coding, entering and debugging a type-in program on a mainframe. This time, how I learned “Computer Science”.
It’s Boulder Startup Week. With so many tech startups in town, there a lot of focus on code and coders. How do you become a developer? What developer career paths are there? Where do I find work? Etc. Etc.
Coincidentally, my mom, who is pruning, sent me a copy of a letter I wrote, more than 30 years ago now, when I was applying to colleges. It I describe how I first learned to program. I had forgotten this story, but I think it’s relevant and worth sharing.
A couple of posts back, I showed off some functions to pop up notifications when a host became pingable again or when a port became reachable. Today’s (semi) quick tip is how to use BASH’s autocomplete functionality add hostname autocompletion to those notifications functions.
BASH autocompletion is a system that provides tab completion of command arguments. You’re familiar with it’s default behavior which is to complete filenames and paths.
1 2 3 4
You can override this behavior by providing BASH with a list of possible completions. The list can be a literal list of words, or it can be a function that looks at the current environment ($PWD, user, time on day, etc) and generates context aware list.
CloudFront is AWS’ CDN. As with any CDN (or any cache for that matter), sometimes you need to clear it in a hurry. In CloudFront, this is don’t with an invalidation and “a hurry” means about 15 minutes. More waiting. The AWS console give you a spinner, but who wants to stare at that?
I hate waiting, but I have to do a lot of it. Waiting for servers to restart. Waiting for services to come up. Waiting around for a Yes or a No. To that end I have a couple of BASH functions that can monitor a server and pop up a notification when it’s up.
A couple of posts back,
I wrote about how you can get status info out of a long running
process by sending it a signal. The functionally is something you can
bring to your own Ruby scripts.
OK, so you know how to get data into AWS S3, what about getting it out? Previously, we uploaded entries from an imagined photo contest into a bucket. We sent a pair of files, a JSON file with the form data and the image. Let’s presume there’s a Rails app, it’s details don’t matter, but it has a model ContestEntry and we want to populate it from the S3 data. We’re going to write a script to do the import.
dd is the *NIX byte copying utility. It’s typically used for copying
disks, creating disk images, or initializing disks from images. It can
also be using to recover damaged files that can’t otherwise be
copied. I mostly use it to make create bootable USB sticks for server
installs. However, it’s also pretty opaque.