In this very long session we went through actual errors in a ZFS pool, we check the Kernel, we remove and reinsert the drive, conduct zpool scrub… in the meantime I talked about Rack, Rack Servers, PSU, redundant components, ECC RAM…
zpool watch is a small Python program for Linux workstations with graphical environment and ZFS, that checks every 30 seconds if your OpenZFS pools are Ok.
If a pool is not healthy, it displays a message in a window using tk inter.
Basically allows you to skip checking from the terminal zpool status continuously or to having to customize the ZED service to send an email and having to figure out how to it can spawn a window alert to the graphical system or what to do if the session has not been initiated.
Since last News from the Blog I’ve released carleslibs v.1.06, v.1.0.5 and v.1.0.4.
v.1.0.6 adds a new class OsUtils to deal with mostly-Linux Os tasks, like knowing the userid, the username, if it’s root, the distribution name and kernel version.
It also adds:
In v.1.0.5 I’ve included a new method for getting the Datetime in Unix Epoc format as Integer and increased Code Coverage to 95% for ScreenUtils class.
v. 1.0.4 contains a minor update, a method in StringUtils to escape html from a string.
It uses the library html (part of Python core) so it was small work to do for me to create this method, and the Unit Test for it, but I wanted to use carleslibs in more projects and adding it as core functionality, makes the code of these projects I’m working on, much more clear.
Minor refactors and adding more Code Coverage (Unit Testing), and protection in the code for division per zero when seconds passed as int are 0. (this was not an actual error, but is worth protecting the code just in case for the future)
Added 20 new pages with some tricks, like clearing the logs (1.6GB in my workstation), using some cool tools, using bind mounts and using Docker in Windows from command line without activating Docker Desktop or WSL.
One of my SATA 2TB 2.5″ 5,400 rpm drive got damaged and so was generating errors, so that was a fantastic opportunity to show how to detect and deal with the situation to replace it with a new SATA 2TB 3.5″ 7,200 rpm and fix the pool.
The company sent me the Stein, which is sent to the employees that serve for two years, with a recognition and a celebration called “The Circle of Honor”.
I bought this book as often I discover new ways, better, to explain the things to my students.
Sometimes I buy books for beginners, as I can get explained what I want to do super fast and some times they teach nice tricks that I didn’t know. I have huge Django books, and it took a lot to finish them.
A simpler book may only talk about how to install and work with it under a platform (Windows or Mac, as instance) but it is all that I require as the command to create projects are the same cross platform.
For example, you can get to install and to create a simple project with ORM, connected to the database, very quickly.
So I just discovered that Zoom has an option to draw in the shared screen, like Slack has. It is called Annotate. It is super useful for my classes. :)
Also discovered the icons in the Chat. It seems that not all the video calls accept it.
As Working From Home I needed an scanner, I looked in Amazon and all of them were costing more than €200.
I changed my strategy and I bought a All-In-One from HP, which costed me €68.
So I’ll have a scanner and a backup printer, which always comes handy.
The nightmare started after I tried to connect it with Ubuntu.
Ubuntu was not recognizing it. Checking the manuals they force to configure the printer from an Android/iPhone app or from their web page, my understanding is for windows only. In any case I would not install the proprietary drivers in my Linux system.
Annoyed, I installed the Android application, and it was requesting to get Location permissions to configure it. No way. There was not possible to configure the printer without giving GPS/Location permissions to the app, so I cancelled the process.
I grabbed a Windows 10 laptop and plugged the All-in-one through the USB. I ran the wizard to search for Scanners and Printers and was not unable to use my scanner, only to configure as a printer, so I was forced to install HP drivers.
Irritated I did, and they were suggesting to configure the printer so I can print from Internet or from the phone. Thanks HP, you’ll be the next SolarWinds big-security-hole. I said no way, and in order to use the Wifi I have to agree to open that security door which is that the printer would be connected to Internet permanently, sending and receiving information. I said no, I’ll use only via USB.
Even selecting that, in order to scan, the Software forces me to create an account.
Disappointing. HP is doing very big stupid mistakes. They used to be a good company.
Since they stopped doing the drivers in Barcelona years ago, their Software and solutions (not the hardware) went to hell.
I checked the reviews in the App Store and so many people gave them 1 star and have problems… what a shame the way they created this solution.
This is a great Open Source, multi-platform editor, so I wanted to support the creator.
Attacks: looking for exploits
This is just a sample of a set of attacks to the blog in a 3 minutes interval.
Another one this morning:
Now all are blocked in the Firewall.
This is a non stop practice from spammers and pirates that has been going on for years.
It was almost three decades ago, when I was the Linux responsible of an ISP, and I was installing a brand new Linux system connected to a service called “infovia”, at the time when Internet was used with dial-up and modems, and in the interval of time of the installation, it got hacked. I had the Ethernet connected. So then already, this was happening.
The morning I was writing this, I blocked thousands of offending Ip Addresses.
I recommend you to use CloudFlare, is a CDN/Cache/Accelerator with DoS protection and even in its Free version is really useful.
So I come with a game kind of Quiz that you can play with your friends, family or work colleagues working from home (WFH).
The idea is that the master shares screen and sound in Zoom, and then the rest connect to jackbox.tv and enter the code displayed on the master’s screen on their own browser, and an interactive game is started.
It is recommended that the master has two monitors so they can also play.
The games are so fun as a phrase appearing and people having to complete with a lie. If your friends vote your phrase, believing is true, you get points. If you vote the true answer, you get points too.
Very funny and recommendable.
<humor>Skynet sent another terminator to end me, but I terminated it. Its processor lays exhibited in my home now</humor>
I bought a laminator.
It has also a ruler and a trimmer to cut the paper.
It was only €39 and I’ve to say that I’m very happy with the results.
It takes around 5 minutes to be ready, it takes to get to the hot-enough temperature, and feeds the pages slowly, around 50 secs a DIN-A4, but the results are worth the time.
I’ve protected my medical receipts and other value documents and the work was perfect. No bubbles at all. No big deal if the plastic covers are introduced not 100% straight. Even if you pass again an already plasticized document, all is good.
One of my friends sent me this image.
It is old, but still it’s fun. So it assumes the cameras of the parking or speed cameras, will OCR the plate to build a query, and that the code is not well protected. So basically is exploiting a Sql Injection.
Anybody working on the systems side, and with databases, knows how annoying are those potential situations.
I tried to continue following it since I left Sanmina. ZFS is really an amazing Software and it’s lead by an amazing Community of super cool Engineers and companies. I would like to continue contributing ASAP.
I bought some new hard drives in order to work a bit on this. You don’t need to have dedicated hardware if you want to test features. You can run in a VirtualBox or VMWare Workstation.
I received more books about DevOps and Python
None is perfect. I see flaws in all of them and bad architecture practices*, however from all I learn interesting things.
You know, I study every day. At least 30 minutes, after work. As part of my healthy routines.
But I also study and learn during the work, as we have time available for this.
I’m very fortunate that Blizzard gives me time every day to study. That’s amazing. They also send us to events paying the ticket, travel, hotel, expenses… now with covid-19 we only go to virtual events, but the company still pay for this and give free days. Is a very nice company.
I continue having purchases of my book, and I’m very happy about that. I’m working on improving it and providing more contents and samples going from the scratch, with step by step code samples. From spaghetti code reading CSV files, to OOP with Full Coverage.
My application for a Higher degree Computer Science Cloud Computing (Level 8) has been accepted. The Irish government pays me 90% of the degree, and Blizzard will pay me the other 10% after I pass the first year course.
I’m really grateful to this beautiful country, Ireland.
Having an Irish degree is something that brings me an special illusion.
I have updated CTOP.py with some interesting features
It allows to pass a fixed width and height for the terminal render. That’s very useful when you run CTOP in a Docker non interactive session, or from a Cron, with the –iterations=1 so the output can be captured programmatically.
Jetbrains has provided me with a Free License of all their products, in order to support my work in Open Source projects. That’s very nice. I’m using now mainly PyCharm and PhpStorm.
At the beginning of the covid-19 I wrote a simulator in Python. That’s why I was able to anticipate that the number of cases and deaths would be very much higher when nobody around me knew what was going to happen. My first simulations were simple, and the algorithms were growing in complexity until I had a full rich Object Oriented modeler. Maybe I’ll write an article about this someday.
After doing a Masterclass to some colleagues about Refactor, Code Reliability, Quality, The non-happy path and Unit Testing, I’m preparing some contents that I’ll publish to the Community soon. So far I created this repo, where I added the source code for lesson 0: starting to program in Python videos that I created few months ago to help beginners.
I also added some contents to lesson 1, where we refactor pure spaghetti code with no error control, to something more elaborated with unit testing and full code coverage. Still procedural, but I will jump to next class in two weeks, where we will move to OOP and Dependency Injection.
Also in the Hackaton I presented my mini utility run_with_timeout.sh to execute a command (zdb, zpool, zfs, or any shell command like ls, “sleep 5; ping google.com”…) with a timeout, and returning a Header with the Error Level and the Error Level itself.