Category Archives: News for the blog

My Sites are under Maintenance

2021-11-08 Update: There is a Postmortem analysis of what happened with Amazon here.

TLTR: I’m undergoing a Maintenance on all my sites.

The main reason was that I was getting unexpected API Exceptions on the AWS SDK for Python (boto3), so I connected to the AWS Console to get more information.

Then I saw a message indicating that they will stop EC2-Classic today 30th of October. (Please read the Update on the Postmortem analysis as I understood incorrectly that banner message)

I already started migrating my Services, some I move to other providers like Digital Ocean. Other I had plant to keep in Amazon.

EOL (End of Life) was scheduled for 2022 August, so when I saw the message from Amazon the evening of the 29th, I decided to migrate my EC2-Classic Public Ip’s and Compute to VPC. Trying to deploy from an AMI, Amazon APIs were returning many internal errors, and as I figured out where their failures would be I was able get instances being launch without being Terminated immediately without an explanation. Still I had many problems with the Internet Gateway, VPC NAT, etc… after hours fighting with their errors, and their console, that is more a bunch of pages to manage Infrastructure rather than a user/developer friendly Cloud Tool I decided that I had enough.

After 11 years using Amazon AWS, including a trip to Dublin to be hired as Manager for Cloud Watch, and giving them the idea to add AutoScaling (I was told the project was too easy for me and that I would get bored in a year or too so I was not hired), I decided to move my Services to Google Cloud and to Digital Ocean.

I’m very polite and I saw that when I told to one Manager that the User Interface was terrible he didn’t like, but I have to speak up and say that tools for developers cannot be cold as your evil girlfriend. Cannot be API alike, stand alone pages to manage infinite parts of Architecture. Web providing services for developers cannot be created like in cold SysAdmin style. If the infrastructure is hard to manage and internally you use APIs, build nice Wizards in Javascript. I was leading a Team of Developers with infinite less resources than Amazon or Google and we wrote a Multi-Cloud product, with nice, and clever, and easy to use Wizards, and they were infinitely more better that those giant CSPs. We won a prize at European level at that time. But it was 2013.

I’ve migrated everything, moved all the data, statics, VMs… but I’m completing the adjustments for certain services like Cassandra nodes, web sites, bootstrapping some of my sites based of my PHP Catalonia Framework, adding Firewall rules to GCP, doing changes for Ansible provisioning, deploying the Server scripts from IaC, Docker, etc…

I’ll be posting updates in Twitter.

News from the blog 2021-10-21

  • I made a Donation to The Document Foundation, which makes the OpenOffice.

I use OpenOffice suite for writing my books and other documents, so I think it’s fair to contribute with their operating costs.

  • I’ve installed a plugin to add Code Highlighting

It also allows me to add blocks of Code, like this:

if CodeHighlighting.b_is_installed == True:
    return VisualImprovement.update_to(10), "It's easy to read"
else:
    return VisualImprovement.get_still_the_same_difficult_to_read(), "The blog lives in the medieval age"

Or Inline Code like print(self.awareness) which is also great

  • I’ve improved a bit, visually, the blog

I modified a bit my template. The changes consist into adding an id attribute to the table for the Quick Selection of the articles, and modifying my template: the styles in the file css/blocks.css and modifying the version in functions.php to reflect the new timestamp.

I also made that when the mouse goes over a link it is displayed in blue, and the already visited in a slightly darker blue.

#articles_selection a:hover {color: #2222FF;}

In the images below you can see the before, the intermediate, and the final.

I’ve also added a button to hide or show the Quick Selection

If you have a WordPress and jQuery does not work for you, with error:

TypeError: $ is not a function

$(document).ready(function(){

This is because for compatibility reasons you have to do different in WordPress:

jQuery(document).ready(function($){
  • I created several videos of 5 minutes to learn Unit Testing in Python 3 with pytest
Learn Python 3 Unit Testing

I also use my package carleslibs to execute the command from shell.

Web CTOP in this case :)

As I did this I discovered a bug (bug #47) in CTOP for setting the number of rows.

  • I fixed the bug #47 and the bug #48 in CTOP and started version 0.8.7 (available in Master).

The changelog.txt file details all the changes for each version.

Here CTOP is displayed with a fixed width and height as by launching with:
ctop.py –rows=50 –columns=170
  • The new PSU arrived and I replaced it on Saturday 16th

After 5 days working nonstop, with no problems, it seems clear that the failing item was the expensive, 850W, Corsair PSU. Sometimes it happens that a new component comes defective, but I paid overprice expecting quality, and it seems that the PSU was defective. Since the beginning the computer powered off every few hours max, so I have to finally assume that effectively it was the PSU. Disappointed with Corsair.

  • Firewall. This month I’ve blocked around 2,000 visitors that were mainly bots searching for exploits

I review the logs several times every day.

Actually I’ve blocked many more Ip’s in the firewall, as when I identify a company source of bots, I block all their range (Imagine, as I block entire class C addresses, there are 256 Ips each class C /24). This has translated into 2,000 visitors less per month to the blog, that were offenders.

  • I added some rules / guidelines to the Leave a Reply section

I moderate all the comments to keep the blog an useful and healthy place.

And I don’t publish Spam, or Marketing messages.

Abusive comments are blocked. Competent Engineers and nice human beings share their points and doubts with data, with technical arguments, with education, in a respectful and polite way. People that cannot observe a minimum decoration are not welcome.

News from the blog 2021-10-10

I published this book to help developers to understand and use Docker.

It is not targeted to SysAdmins, is aimed to Developers that want to get an operative know how by examples very quickly, and easy to read.

  • University classes are restarted, and I fixed my tower.

For the Cloud computing degree this semester VMWare is used intensively.

I have a dedicated tower with an AMD Ryzen 7 processor, a Samsung NMVe drive PCIe 4.0, which provides me a throughput of 6GB/second (six Gigabytes, so 48 Gbit/second), SAS drives and SATA too. It’s a little monster with 64 GB of RAM and 2.5 Gbps NIC.

It was not starting.

The problem was in the Video card, which made loosely contact to the motherboard.

I had to disconnect everything until I found what it was, but after moving the video card to another PCI slot, it worked.

I knew it was some sort of short circuit / bad contact as the fans were turning for a second and turning off immediately.

After this, the computer works fine but it will poweroff in about 4h and 12 hours. I’ve been testing and removing each component until I believe is the PSU. I’ve ordered a new one from a Dutch provider with web store in Ireland that my former colleague Thomas showed me one year and half ago.

Since England leaved the EU, it is impossible to buy from amazon.co.uk without experiencing problems in the border and delays.

If you want to learn how to assemble a PC, fix the problems and upgrade your laptop, I wrote this book:

https://leanpub.com/pc-assemble/

If you are curious about what I use in my day to day:

  1. A tower for developing and reading my email, with Linux, Intel i7 7800X (12 cores) and 64 GB of RAM, with Nvidia graphics card
  2. A tower for holding Virtual Machines, with Linux, AMD Ryzen 7 3700x (16 cores) and 64 GB of RAM, with Nvidia graphics card
  3. An upgraded HP laptop for programming in the cafe, is a Windows 10, with 16 GB of RAM
  4. Raspberry Pi 4 and 3, from time to time
  5. A laptop for programming, for Work, 16 GB of RAM
  6. A tower for programming, for Work, at the office, 32 GB of RAM
  7. I also had a Dell computer which battery inflated elevating the touchpad, an Acer 11.6 Latop very lightweight which screen died cracked apparently (it’s a mistery to me how this happened as I removed from the bag and it was cracked. That little laptop accompanied me during years, to many countries, as for a while I carried it with me 100% of the time. At that time if the companies I worked for had outages they were losing thousands of euros per hour, so as CTO I fixed broken stuff even in a restaurant. Believe when I recommend you and your teams to use Unit Testing) and a 15.6″ Acer with 16GB of RAM that was part of the payment of an Start up I was CTO for, and which screen flicks intermittently and I managed to fix it by applying a pressure point to a connector, so I managed to use as fixed computer at the beginning of being in Ireland. I was not using it much, as I had two laptops from work when working for Sanmina, a Dell with 16 GB of RAM and Core i7 with two external monitors and an Intel Xeon with 32GB of RAM, heavy weight, but very useful for my job (programming, doing demos, having VMs…).

I’ve assembled all my PC from the scratch, piece by piece, and I force myself to do it so I keep up to date of the upcoming technologies, buses, etc…

  • My students are doing well. Congrats to Albert for getting 8.67 from 10 in his university programming course exams!.
  • Diablo 2 Resurrected is published and I am in the credits :)

I’m in the credits of all our games since I joined, but I’m happy every time I see myself and my colleagues on them. :)

This release includes SubProcessUtils which is a class that allows you to execute commands to the shell (or without shell) and capture the STDOUT, STDERR, and Exit Code very easily.

I’ve used my libraries for a hackaton PoC for work, for Monitoring one aspect of one of our top games side, and I coded it super quickly. :)

They loved it and we have a meeting scheduled to create a Service from my PoC. :)

News from the blog 2021-09-20

  • I’ve published a very simple game, Tic Tac Toe, that I created for my Python 3 Exercises for Beginners book.
  • I’ve raised back the price for my books to normal levels.
    I’ve been keeping the price to the minimum to help people that wanted to learn during covid-19. I consider that who wanted to learn has already done it.

I still have bundles with a somewhat reduced price, and I authorized LeanPub platform to do discounts up to 50% at their discretion.

Bundle of four books in https://leanpub.com/b/python3-exercises-zfs-assemble-computer

https://leanpub.com/b/python3-exercises-zfs-assemble-computer

  • I’ve been deleting AMIs, Snapshots, Volumes and backups from Amazon instances I’ll no longer use.

I’ve migrated to Docker some sites and WordPress sites and now I’m CSP (Cloud Service Provider) agnostic. I can deploy wherever I want.

We pay per GB used of storage, so my money will get a better usage.

As I said in my old article from 2013, The Cloud is for Scaling. For Startups and for Enterprises. It is too expensive for small and medium companies.

  • For those studying Python there is a Virtual Meetup about Data Analysis, in Spanish ,the 23th of September

https://www.meetup.com/tech-barcelona/events/280791310/

More meetups:

https://www.meetup.com/tech-barcelona/

News from the blog 2021-09-07

  • Blocking Ip addresses in the firewall

I’ve been blocking entire ranges from Cloud Providers, as some of their Ip’s were being used to try to hack/abuse the blog.

After some time blocking individual Ip’s, I opted for being some more effective and blocking /24 (the class C for the offending Ip).

If you work for a CSP and you can’t see my blog from your range, this is the reason.

  • I have updated my two Python books.

For Python 3 simple exercises for beginners I’ve added this new content:

v.0.29 and v.0.28 Python 3 Simple Exercises for Beginners
Added a new section Games, with a first game “Guess my number”

Provided a solution for the recipe Exercise 3: Create a function that will ask a user for a number from Keyboard input, and return the result, only when the value is between the accepted ranges.

Added two new questions to the Quiz section.

Fixed a docstring in Recipes Exercise 4, referring to a String return value which it was an Integer.

Added an exercise for retrieving a JSON with your public Ip

Added a new exercise for converting bytes to kilobytes with two decimal positions.

Added a new exercise / recipe to SSH to a Server with Username and Password and execute a command, using the Paramiko library.

For Python 3 Combat Guide I have added this new content:

v.1.02 Python 3 Combat Guide

Added a new exercise / recipe to SSH to a Server with Username and Password and execute a command using Paramiko library. I added two examples executing commands uptime and df -h /

Show an alternative way to run Flask apps.

Added new interesting packages.

As long as covid is active I plan to keep the minimum price of each of my books at the minimum accepted by LeanPub which is USD $5.

I also enable bundles and enable LeanPub to make punctual discounts to make them even more affordable to humble pockets.

  • I’m going to teach an initiation to programming class, a live Zoom session of 1 hour, plus 15 minutes for questions, for Free. It will be a very basic starting class for absolute beginners.

It will be performed at a time around 19:00 Irish time, wich is 11:00 AM in Irivine, CA time, to maximize the opportunities for people to assist.

If you would like to join, write me an email:

There are not many spots available, but if there is no room for you this time I may contact you for the next time.

This version adds class StringUtils, and a set of methods to perform different useful tasks with Strings, like converting a number to the biggest unit with sense, like a large number of bytes to PB, a smaller one to TB, or GB, MB, KB, justifying strings to the right or to the left, and cap the number of chars to a specified one, etc…

I have many libraries that I’ve been building across the years, and I’m liberating them as Open Source, as soon as I have time to make sure that are compatible with Python 3.5 or superior (and with Python 2.6 when possible), and I have time to add a decent Unit Testing Code Coverage.

I try to release libraries that have no other dependencies. After that I’ll start releasing my libs that have dependencies, like to work with MySQL, SQLite, web scrapping, etc…

News of the blog 2021-08-16

  • I completed my ZFS on Ubuntu 20.04 LTS book.
    I had an error in an actual hard drive so I added a Troubleshooting section explaining how I fixed it.
  • I paused for a while the advance of my book Python: basic exercises for beginners, as my colleague Michela is translating it to Italian. She is a great Engineer and I cannot be more happy of having her help.
  • I added a new article about how to create a simple web Star Wars game using Flask.
    As always, I use Docker and a Dockerfile to automate the deployment, so you can test it without messing with your local system.
    The code is very simple and easy to understand.
mysql> UPDATE wp_options set option_value='blog.carlesmateo.local' WHERE option_name='siteurl';
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0

This way I set an entry in /etc/hosts and I can do all the tests I want.

  • I added a new section to the blog, is a link where you can see all the articles published, ordered by number of views.
    /posts_and_views.php

Is in the main page, just after the recommended articles.
Here you can see the source code.

  • I removed the Categories:
    • Storage
      • ZFS
  • In favor of:
    • Hardware
      • Storage
        • ZFS
  • So the articles with Categories in the group deleted were reassigned the Categories in the second group.
  • Visually:
    • I removed some annoying lines from the Quick Selection access.
      They came from inherited CSS properties from my WordPress, long time customized, and I created new styles for this section.
    • I adjusted the line-height to avoid separation between lines being too much.
  • I added a link in the section of Other Engineering Blogs that I like, to the great https://github.com/lesterchan site, author of many super cool WordPress plugins.

News from the blog 2021-07-23

  • I’ve released v. 0.99 of carleslibs package
    This package includes utilities for:
    • Files and Directories handling
    • Date/Time retrieval
    • Python version detection

You can install it with:

pip install carleslibs

The minimum requirement declared is Python 3.6, although they work with Python 3.5 and Python 2.7, as I want to drop support for no longer supported versions.

Instructions can be found in here: carleslibs page.

News from the Blog 2021-07-01

  • Google Instances’ Performance
    I’ve updated the CMIPS score for the latest Google instances vs last Amazon’s I tried and baremetals.

This is the changelog for latest version:

v. 0.99
 A whole new chapter showing sorting in Python and lambdas. (.sort() and sorted() package First)

 I show writing lambdas for Sorting, and also what makes them crash.

 Explained why Lambdas are not recommended unless you use for working with data, like for sorting or filtering out, and unless you know what you are doing. They are difficult to Debug.

 Explained about PEP8 tool to validate style.

 Explaining why we define Instance variables in the Constructor.

 Provided more samples for Flask Applications.

 Fixed code sample https://gitlab.com/carles.mateo/python_combat_guide/-/blob/master/src/keywords.py as the editor removed the white line spaces.

 Added more books to the bibliography

 I explain the importance of running Unit Testing as both root and as regular users.

 Explain how to run as regular user inside a Docker Container.

 Explained requirements.txt file. And how integrates PyCharm to create venv/ Virtual Environment.

 Also how it is used in Dockerfile to make sure all the dependencies are satisfied in the Docker Container.

As any project committed to saving human lives, she has all my support and admiration.

News from the Blog 2021-05-22

  • The company has provided me and the members of my Team with unlimited Cloud capacity for testing and developing. That’s very nice. I plan to run some nice workloads to asses the performance of several solutions.
  • I’ve had tons of assignments from the university and with the classes to my students I had no much time.
  • The Health Department and the universities (CIT and UCC) offered free PCR for the students. I can only say Kudos again for Ireland.
  • They also offered certain more vulnerable students to vaccinate with Pfizer. More Kudos.
  • I bought some cases for Raspberry Pi 4.
  • I’ve bought a Wi-fi Mesh TP-Link to repeat the Wifi signal to zones of the house it was arriving weak. I’m very satisfied with this signal repeater.

This little buddy also provides an Ethernet to connect to a laptop or to a switch.

So far I have only tested with a laptop and works great.

  • I’ve written one article about the GUI Software I use on Linux Desktops.
  • I wrote another article about cloning applications you’ve working in other Linux Desktops under Wine.
  • I also released CTOP TAG v.0.8.4 and fixed some bugs in upcoming CTOP v.0.8.5 and added a new feature to display the File Descriptors in use and the Max FDs set in the Kernel. This feature needed some work as I did calculating all the FDs per process but Kernel has another value that comes from /proc/sys/fs/file-nr so I finally implemented this last value, fixed a bug in conversion of units with decimals (KBs without the decimal part) and added Unit Testing to check this cases. I was satisfied to release v. 0.8.5.

News for the blog 2021-03-21

  • I’ve released cmemgzip v. 0.4.1, with colors, and is now a package available to install download from PIP.
pip3 install cmemgzip
  • I keep teaching to learn to program in Python, to become a Junior BackEnd Developer. To groups and individuals.
    It is so beautiful and wonderful seeing people transform their minds, their lives and their confidence with the coding skills and being able to chase after better jobs, and so funny and beautiful when this happens in a group dynamic, with friendship, that I’m thinking about assembling a new Group of Students.
    Those classes are in English but I got some suggestions to do group classes in Spanish. Even if Catalan is speak by around 11 Million people in the world if I have enough requests I’ll gladly do it.
    if you’re interested reach me in LinkedIn.
  • This new is hilarious:

https://www.engadget.com/icloud-true-last-name-lock-out-192224309.html

One person named True as surname gets locked in iCloud due to a bug in their coding, confusing the surname by a boolean property.

  • Bugs everywhere.

I always smile when I find bugs. Bugs are everywhere, but always make me smile when important companies with tons of resources make them.

Today I show this bug received in my email from Glassdoor. :)

You can see how in the email they assume that key will exist, and doesn’t, so a KEY NOT FOUND error is displayed. :)

It is funny, but remembers us the importance of doing our best trying to avoid bugs, working seriously with Methodology, implementing Unit Testing, Functional Testing, having also QA.. all the mechanisms we can, as they can be the last line of defense to avoid releasing bugs to Production.

  • In the past I taught Java and PHP, and I still help my mates with their Assembler Practices in their Masters, so I could not stop laughing with this: