Automating installation/updates of the AWS CLI on Linux

Are you annoyed that there are no native Linux packages for the AWS CLI (deb, rpm…)? And, thus, no repositories? I am, a bit.

But it’s also true that the installation is not difficult at all, right? Well, yes, if you want to install it in locations different than the defaults (e.g. your user’s home directory) and on more than one machine you still have to do some work, but it’s not terrible, is it?

Then, one day, you find that one of the AWS CLI commands you need to use was added in a newer version than the one you are running, so you have to update the AWS CLI on all machines, and possibly rediscover the parameters you used during the initial installation. Are you happy with that?

I am not, and I decided to do something to automate the process: a Makefile, the simplest form of automation you can have on UNIX systems. Here you go: aws-cli-manager on github.

If you find it useful, I am happy. And if you want to support more Linux distributions or more operating systems (MacOS should be fairly easy, I expect), just go ahead and throw me a pull request. Enjoy!

Remmina: a full featured remote desktop client for Linux

If you are a Linux user and you find yourself in need to connect to a remote Windows server desktop, I hereby recommend that you give Remmina a try.

At my new job I have to check into Windows servers at times (eh, I know, it’s a cruel world…) through the RDP protocol. We have some tooling available that, given the name of a VM, will look up from various sources all information necessary to connect to that machine and build a Remote Desktop Connection file (“.rdp”). The problem: Vinagre, the standard GNOME RDP client, doesn’t know what to do with that file, so I had to find another client.

Enter Remmina.

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From AWS instance IDs to private DNS names

github-logoJust a small bash snippet for those cases where, for example, a command returns AWS instance IDs but not the matching DNS names or an IP addresses. The function id2dns, that you can add to your .bashrc file, will do the translation for you. In order to use the function you will:

  • ensure you have the aws CLI installed and functional;
  • ensure you have jq command available;
  • ensure you have valid AWS credentials set, so that your aws CLI will work.

Enjoy!

Update 2020-08-14: jq not needed any more

 

Creating and terminating test instances in AWS quickly

This is mostly a note to self. When I need an EC2 instance to run a quick test, it may be overly annoying to provision one through the web console, or it may feel a bit overkill to do that using large frameworks like terraform. Using the AWS command line is just fine, if you know what command to run with which parameters, and it pays off quickly if, to run your tests, you use the settings often (AMI, subnet, security groups…) or if during the same test session  you need to scrap and rebuild test instances a few times. Here is an example on how to do so with the AWS command line client.

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An update to cf-keycrypt

I have published a small update to cf-keycrypt, so that it’s now easier to compile the tool on Debian systems and it’s compatible with CFEngine 3.15. You can find it here.

For those who don’t know the tool, I’ll try to explain what it is in a few words. The communication between CFEngine agents on clients and the CFEngine server process on a policy hub is encrypted. The key pairs used to encrypt/decrypt the communication are created on each node, usually at installation time or manually with a specific command. cf-keycrypt is a tool that takes advantage of those keys to encrypt and decrypt files, so that they are readable only on the nodes that are supposed to use them. The fact that the keys are created on the nodes themselves eliminates the need to distribute the keys securely.

cf-keycrypt was created years ago by Jon Henrik Bjørnstad, one of the founders of CFEngine (the company). The code has finally landed the CFEngine core sources as cf-secret, but it’s not part of the current stable releases. I had an hard time trying to compile it, but I made it with good help from the CFEngine help mailing list. I decided to give the help back to the community, publishing my updates and opening a pull request to the original code.  Until it’s merged, if it ever will, you can find my fork on my github.

cf-deploy v4 released

After five years after the release of cf-deploy v3, I have just released cf-deploy v4. This version of cf-deploy fixes a number of shortcomings that made their way up to this point and that I wasn’t able to see until recently. It is now more flexible and easier to configure than it ever was. In particular, the documentation is way more comprehensive, covering installation, configuration and usage. The documentation also covers some of the internals, that will allow the hardcore user to fine tune the tool to better suit their needs.

You will find cf-deploy on github, as always. Enjoy!

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How to boot into a non-standard runlevel/target to rescue a Linux system

Recently, while testing a configuration of Linux on a Lenovo laptop, I messed up. I had rebooted the laptop and there were some leftovers around from an attempted installation of the proprietary Nvidia driver. The system booted fine and was functional, but those leftovers where enough to make the screen go blank. The fix is easy, if you can enter the system in some other way: log in and remove anything related to the Nvidia driver. But unfortunately the only way to log in was from the console, so I was “de facto” locked out.

The first attempt to get out of the mud was to force a reboot of the system and in rescue mode. The system booted well, but after I typed the root password the  boot process went a bit too far, loaded the infamous leftovers of the driver and here we go again, with a blank screen.

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Down the rabbit hole: installing software

Preface

This article is about using configuration management to install software on your own computers (e.g. your laptops, or the computers used by your family and relatives) and how the complexity of this task is easy to overlook, no matter if you are a newbie or an expert.

If you already know about configuration management and how it makes sense to use it at a small scale like, again, your own computers or your family’s, you can just skip at the section “New job, new setup”.

If you already know about configuration management and you are asking yourself why it should make sense to use it at a small scale, I suggest that you start a section earlier, at Personal configuration management”.

If you are new to configuration management, or you wonder what could be difficult in installing software on a set of systems, I suggest that you read the whole article.

In any case, happy reading!

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A multi-platform API client in Go

In the last few months I have been working, together with a colleague, on an API client for several well-known systems and cloud providers. When we started, I was a novice in the Go programming language, I had no experience in programming API clients, and I trusted the makers of the APIs enough to have great expectations at them.

Today, a few months later, several hours programming later and a bunch of lines of code later, I am a better novice Go programmer, I have some experience in interfacing with APIs, and my level of trust in the API makers is well beneath my feet.

This article will be a not-so-short summary of the reasons why we started this journey and all the unexpected bad surprises we got along the way. Unfortunately, I will be able to show only snippets of the code we have written because I didn’t get the authorisation to make it public. I will make the effort to ensure that the snippets are good enough to help you get a better understanding of the topics.

OK, enough preface. It’s time to tell the story.

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