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  • Cassandra Universal Driver
    A HTTP gateway for all the languages supporting curl/sockets. Written in 2014, a time when there were no drivers for many languages.
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Old News:

Install jenkins on Docker in ubuntu in 4 minutes

Following the official documentation:


The steps are:

Create the network bridge named jenkins

docker network create jenkins

to execute Docker commands inside jenkins nodes we will use docker:dind

docker run \
  --name jenkins-docker \
  --rm \
  --detach \
  --privileged \
  --network jenkins \
  --network-alias docker \
  --env DOCKER_TLS_CERTDIR=/certs \
  --volume jenkins-docker-certs:/certs/client \
  --volume jenkins-data:/var/jenkins_home \
  --publish 2376:2376 \
  docker:dind \
  --storage-driver overlay2

Created a Dockerfile with these contents:

FROM jenkins/jenkins:2.346.1-jdk11
USER root
RUN apt-get update && apt-get install -y lsb-release
RUN curl -fsSLo /usr/share/keyrings/docker-archive-keyring.asc \
RUN echo "deb [arch=$(dpkg --print-architecture) \
  signed-by=/usr/share/keyrings/docker-archive-keyring.asc] \
  https://download.docker.com/linux/debian \
  $(lsb_release -cs) stable" > /etc/apt/sources.list.d/docker.list
RUN apt-get update && apt-get install -y docker-ce-cli
USER jenkins
RUN jenkins-plugin-cli --plugins "blueocean:1.25.5 docker-workflow:1.28"

Build it:

docker build -t myjenkins-blueocean:2.346.1-1 .

Run the Container:

docker run \
  --name jenkins-blueocean \
  --restart=on-failure \
  --detach \
  --network jenkins \
  --env DOCKER_HOST=tcp://docker:2376 \
  --env DOCKER_CERT_PATH=/certs/client \
  --publish 8080:8080 \
  --publish 50000:50000 \
  --volume jenkins-data:/var/jenkins_home \
  --volume jenkins-docker-certs:/certs/client:ro \

See the Id of the running Containers:

docker ps

As in my case my jenkins container Id is 77b6a5a7ae8d in order to know the jenkins administrator password I check the logs for my jenkins Container with docker logs 77b6a5a7ae8d:

docker logs 77b6a5a7ae8d
Running from: /usr/share/jenkins/jenkins.war
webroot: EnvVars.masterEnvVars.get("JENKINS_HOME")
2022-06-26 21:02:05.492+0000 [id=1]	INFO	org.eclipse.jetty.util.log.Log#initialized: Logging initialized @549ms to org.eclipse.jetty.util.log.JavaUtilLog
2022-06-26 21:02:05.583+0000 [id=1]	INFO	winstone.Logger#logInternal: Beginning extraction from war file
2022-06-26 21:02:05.613+0000 [id=1]	WARNING	o.e.j.s.handler.ContextHandler#setContextPath: Empty contextPath
2022-06-26 21:02:05.674+0000 [id=1]	INFO	org.eclipse.jetty.server.Server#doStart: jetty-9.4.45.v20220203; built: 2022-02-03T09:14:34.105Z; git: 4a0c91c0be53805e3fcffdcdcc9587d5301863db; jvm 11.0.15+10
2022-06-26 21:02:05.986+0000 [id=1]	INFO	o.e.j.w.StandardDescriptorProcessor#visitServlet: NO JSP Support for /, did not find org.eclipse.jetty.jsp.JettyJspServlet
2022-06-26 21:02:06.020+0000 [id=1]	INFO	o.e.j.s.s.DefaultSessionIdManager#doStart: DefaultSessionIdManager workerName=node0
2022-06-26 21:02:06.020+0000 [id=1]	INFO	o.e.j.s.s.DefaultSessionIdManager#doStart: No SessionScavenger set, using defaults
2022-06-26 21:02:06.021+0000 [id=1]	INFO	o.e.j.server.session.HouseKeeper#startScavenging: node0 Scavenging every 600000ms
2022-06-26 21:02:06.463+0000 [id=1]	INFO	hudson.WebAppMain#contextInitialized: Jenkins home directory: /var/jenkins_home found at: EnvVars.masterEnvVars.get("JENKINS_HOME")
2022-06-26 21:02:06.647+0000 [id=1]	INFO	o.e.j.s.handler.ContextHandler#doStart: Started w.@7cf7aee{Jenkins v2.346.1,/,file:///var/jenkins_home/war/,AVAILABLE}{/var/jenkins_home/war}
2022-06-26 21:02:06.668+0000 [id=1]	INFO	o.e.j.server.AbstractConnector#doStart: Started ServerConnector@4c402120{HTTP/1.1, (http/1.1)}{}
2022-06-26 21:02:06.669+0000 [id=1]	INFO	org.eclipse.jetty.server.Server#doStart: Started @1727ms
2022-06-26 21:02:06.669+0000 [id=25]	INFO	winstone.Logger#logInternal: Winstone Servlet Engine running: controlPort=disabled
2022-06-26 21:02:06.925+0000 [id=32]	INFO	jenkins.InitReactorRunner$1#onAttained: Started initialization
2022-06-26 21:02:07.214+0000 [id=39]	INFO	jenkins.InitReactorRunner$1#onAttained: Listed all plugins
2022-06-26 21:02:10.781+0000 [id=47]	INFO	jenkins.InitReactorRunner$1#onAttained: Prepared all plugins
2022-06-26 21:02:10.794+0000 [id=35]	INFO	jenkins.InitReactorRunner$1#onAttained: Started all plugins
2022-06-26 21:02:10.803+0000 [id=42]	INFO	jenkins.InitReactorRunner$1#onAttained: Augmented all extensions
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.vmplugin.v7.Java7$1 (file:/var/jenkins_home/war/WEB-INF/lib/groovy-all-2.4.21.jar) to constructor java.lang.invoke.MethodHandles$Lookup(java.lang.Class,int)
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.vmplugin.v7.Java7$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
2022-06-26 21:02:11.634+0000 [id=30]	INFO	jenkins.InitReactorRunner$1#onAttained: System config loaded
2022-06-26 21:02:11.635+0000 [id=30]	INFO	jenkins.InitReactorRunner$1#onAttained: System config adapted
2022-06-26 21:02:11.642+0000 [id=48]	INFO	jenkins.InitReactorRunner$1#onAttained: Loaded all jobs
2022-06-26 21:02:11.645+0000 [id=46]	INFO	jenkins.InitReactorRunner$1#onAttained: Configuration for all jobs updated
2022-06-26 21:02:11.668+0000 [id=67]	INFO	hudson.model.AsyncPeriodicWork#lambda$doRun$1: Started Download metadata
2022-06-26 21:02:11.675+0000 [id=67]	INFO	hudson.model.AsyncPeriodicWork#lambda$doRun$1: Finished Download metadata. 4 ms
2022-06-26 21:02:11.733+0000 [id=52]	INFO	jenkins.install.SetupWizard#init: 


Jenkins initial setup is required. An admin user has been created and a password generated.
Please use the following password to proceed to installation:


This may also be found at: /var/jenkins_home/secrets/initialAdminPassword


2022-06-26 21:02:22.901+0000 [id=52]	INFO	jenkins.InitReactorRunner$1#onAttained: Completed initialization
2022-06-26 21:02:23.013+0000 [id=24]	INFO	hudson.lifecycle.Lifecycle#onReady: Jenkins is fully up and running

In my case the password is at the bottom, between the stars: 3de0910b83894b9294989552e6fa9773

Go with your browser to: http://localhost:8080

How to deploy a DigitalOcean droplet (instance) and use userdata

You can see how to deploy a new droplet also named Instance or VM to DigitalOcean Cloud Provider in this video.

You can see how User Data works in this other video.

The userdata script is run as root the first time the instance is deployed.

I provisioned using this userdata script:


sudo apt update && sudo apt install -y net-tools vim mc htop less strace zip gzip lynx curl wget git apache2

cd /opt/
git clone https://gitlab.com/carles.mateo/ctop.git

If you look for ctop.py check this page:


For information about User Data from Digital Ocean:


News from the Blog 2022-06-22

For the first part of June I’ve been quiet on Social Media as I was on holidays and taking some scheduled tests for my health in the hospital.

Carles in the Media/Press/Streaming


I started streaming live Python coding sessions in Twitch. I’m giving it a try to see if coders have engagement.

The Software I use to broadcast from Linux is OBS.

I started with my Open Source project ctop.

I had a very long and interesting session on 2022-06-06 about OpenZFS, Data Centers, NVMe, iSCSI, Hard Drives, Storage, performance, Data Centers

More funny things happened like when I was installing a VirtualBox VM live, and the ZFS pool became irresponsible due hardware errors in one SATA Spinning drive.

Things from broadcasting live…

Some of the feedback I got from talented Engineers is that even if the original matter to talk about was interesting, seeing everything falling apart live due to unexpected hardware problems, and me troubleshooting live is being the best of the show… which I found very amusing.

RAB Radio the new digital world

I keep doing my radio space for Radio America Barcelona, once per week, addressed to the Catalan Community across the world and expats.

This radio program, streamed also via Twitch, is available in Catalan language only. RAB.

Open Source


I’ve been working in version 1.0.8 branch, and after a session of refactor on Twitch where I found a bug in MenuUtils class, I fixed it and released v. 1.0.8. You can see the video on the link.

Now I’m working on the branch v. 1.0.9.


I’ve been working in the branch 0.8.9.

My first Twitch broadcast was about adding Unit Testing to MemUtils class.

You can see all my videos:




I recommend you the videos in this page about Operating OpenStack at Scale.

Some of my Blizzard colleagues talk on it.


My last physical server in a Data Center

This week I decommissioned my last physical server in a Data Center.

It has been a long journey since I created my company to launch my own projects, and I started having my own infrastructure, back at 2000.

I was offering VPS at that time, with VMWare as Hypervisor.

This last Rack Server served me well for 21 years.

Now everything is Cloud, and is not viable to host and maintain servers unless this is your main occupation. Server’s motherboards die, hard drives die and they need to be replaced. Maintaining infrastructure it’s a full time job and you require somebody to do it. Also using fixed servers only prevents you from moving fast, locks a lot of money, and from spawning more compute capacity.

If you are curious this Rack Server is a Super Micro with Intel Xeon processor and SCSI drives.



I keep blocking thousands of IP Addresses every day.

When I see a pattern of an IP trying an attacks against the Server I look at the IP and if it’s from a hosting provider I just block the entire range.

I keep blocking any IP Address coming from Russia or Belarus since they invaded Ukraine.

My Health

I visited the hospital for a programmed following on my health.

The analysis are super good, and it’s super clear that I’ve improved radically. My discipline with the diet, taking the medicines and doing exercise regularly has been crucial.

My Doctor is confident that I’ll have a full recovery, but to do so I need to loss a lot of weight in a year or two.

So, I need to focus on my health and in doing exercise, being happy and avoid any kind of negative stress.

The cost of the travels and the medicines have put some stress into my economy, but I’m fortunate that I can handle it.

Entertainment / Life / Reflections

Star Wars and racism

I’m really enjoying new Start Wars series Obi Wan, and I’ve been profoundly shocked to read that there are fans being racist against the black characters.


So just writing here to show my support to human beings from all races, genders including transgender, LGTB+, conditions and preferences.

Fixing the Error Can’t locate IPC/Run.pm in @INC in CentOS 7.5

So if you get an error like this:

Can't locate IPC/Run.pm in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at ./check_ipmi_sensor line 35.
BEGIN failed--compilation aborted at ./check_ipmi_sensor line 35.

The solutions is simple.

sudo yum makecache

yum install perl-IPC-Run

You’ll see the list of mirrors and an output similar to this:

Loaded plugins: fastestmirror, versionlock
Loading mirror speeds from cached hostfile
centos-updates                                                                                                                                          | 3.4 kB  00:00:00
epel                                                                                                                                                    | 4.7 kB  00:00:00
extras                                                                                                                                                  | 3.4 kB  00:00:00
Resolving Dependencies
--> Running transaction check
---> Package perl-IPC-Run.noarch 0:0.92-2.el7 will be installed
--> Processing Dependency: perl(IO::Pty) >= 1.08 for package: perl-IPC-Run-0.92-2.el7.noarch
--> Running transaction check
---> Package perl-IO-Tty.x86_64 0:1.10-11.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

 Package                                     Arch                                  Version                                    Repository                                  Size
 perl-IPC-Run                                noarch                                0.92-2.el7                                 centos-base                                122 k
Installing for dependencies:
 perl-IO-Tty                                 x86_64                                1.10-11.el7                                centos-base                                 42 k

Transaction Summary
Install  1 Package (+1 Dependent package)

Total download size: 163 k
Installed size: 397 k
Downloading packages:
(1/2): perl-IO-Tty-1.10-11.el7.x86_64.rpm                                                                                                               |  42 kB  00:00:00
(2/2): perl-IPC-Run-0.92-2.el7.noarch.rpm                                                                                                               | 122 kB  00:00:11
Total                                                                                                                                           15 kB/s | 163 kB  00:00:11
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : perl-IO-Tty-1.10-11.el7.x86_64                                                                                                                              1/2
  Installing : perl-IPC-Run-0.92-2.el7.noarch                                                                                                                              2/2
  Verifying  : perl-IPC-Run-0.92-2.el7.noarch                                                                                                                              1/2
  Verifying  : perl-IO-Tty-1.10-11.el7.x86_64                                                                                                                              2/2

  perl-IPC-Run.noarch 0:0.92-2.el7

Dependency Installed:
  perl-IO-Tty.x86_64 0:1.10-11.el7


Twitch Stream about ZFS, zpool scrubbing, Hard drives, Data Centers, NVMe, Rack Servers…

Twitch stream on 2022-06-06 10:50 IST

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…

Sorting an Array of Tuples in Python

In this video I show a nice way to work with Data in Python, by using Tuples.

I also show how to easily and conveniently sort the Data based on your preferred criteria by using lambdas.

What happens if we have accents, ç, Ç etc…

You can download the code from:


Fixing the problems installing napalm-base in Ubuntu 20.04 LTS

One of my friends wanted to use SaltStack and https://github.com/napalm-automation/napalm-salt

But he had problems installing napalm-base package.

Note that the package is no longer maintained.

He tried with the last one, and with the previous one (0.25.0), but he always got the error: ModuleNotFoundError: No module named ‘pip.req’

pip3 install napalm-base==0.25.0

Defaulting to user installation because normal site-packages is not writeable
Collecting napalm-base==0.25.0
  Using cached napalm-base-0.25.0.tar.gz (35 kB)
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error
  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [6 lines of output]
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line 34, in <module>
        File "/tmp/pip-install-gzd07xzq/napalm-base_aace1b03ac0e4045bbc85e27c788ebc1/setup.py", line 5, in <module>
          from pip.req import parse_requirements
      ModuleNotFoundError: No module named 'pip.req'
      [end of output]
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.

TL;TR: The problem is that pip version 10, changed the structure for req.

There are several solutions that can be done to make it work, but the easiest way is to downgrade pip, and install the package. After pip can be upgraded again.

python -m pip install pip==9.0.3
pip3 install napalm-base

News from the Blog 2022-05-22

Media, Press, Radio

I was contributing already but since the 2th of May I started my radio space, also streamed in Twitch, google Podcast, Apple, Spotify… in Radio America Barcelona.

My space is named The New Digital World (“el nou món digital”) and I talk about tech news, technology, videogames and handy tricks.

This content is in Catalan language only, so I added to the blog as ending in [CA]

New Projects: Erasure Code

For my university thesis I’ve been creating an Erasure Coding solution that allows to encode and distribute the files seamlessly across an universe of Servers in different cloud providers, balancing the disk space used, super easy to use, and resilient to disaster and recovery.

I created my project, named Erasure Code www.erasurecode.com as Open Source, so all size of companies will be able to benefit from this technology, only available to multinationals until now.

Here you can watch a presentation and a demo:

Erasure Code project

I hope this will help tons of companies and startup, hopefully scientific startups, to save costs and focus more in their business and to make a better world.

My final presentation was the 20th of May.


Python Combat Guide

I’ve updated my book Python Combat Guide with few additions.

Currently is 405 pages DIN-A4 size plus gitlab downloadable code.

It can be downloaded as PDF DRM-free.

Updates to this version 1.08 2022-05-11:

  • Added an example of .copy() for Arrays and mention to deepcopy()
  • Example on how to sort a dictionary of key/counter
  • Improvements to MT Notation updated
  • Added packages recommended: colorama, pynput, bisect
  • Added Personal WebServer examples.
  • Added examples of Python misbehaving with Floats.
  • Explanations about redefining reserved keywords like print or exit as a variable.
  • Style modification to add lines over the line number and over the Footnote.

My health

My health is improving.

Thanks to my self discipline, following a good diet, taking the medicines… I’ve seen an spectacular improvement since I was sent urgently to he hospital with risk for my life.

I’ve very grateful that amazing doctors care of me.

I had some ups and downs and downs while pushing to finish my final project for the HDip in Computer Science Cloud Computing, but I managed to complete everything on time.

I had to travel to visit amazing specialists, and had to pay the expensive treatments, however everything worked and my health has improved drastically. I am very happy to count with additional source of income, like the teaching programming and my technical books, which helped me to be able to deal with all these sorts of unexpected expenses. I appreciate every single sale of my books, as it made me feel useful and appreciated when I was a bit low, and the nice details some of the readers had. Thanks.


I’ve keep blocking in the Firewall any IP and that network coming to the blog from Russia and Belarus. I’ve blocked millions of IP Addresses so far.

I’ve also blocked the traffic coming from CSP when I detect an attack and the IP belongs to them. Most of the attacks were coming from Digital Ocean, after your-server.de and hetzer.de and finally Amazon. Curiously some attacks came from IPs from Microsoft.

I’ve blocked all these ranges of IPs, hundreds of thousands.

Despite blocking all these IPs from CSPs, the number of visitors keeps growing.

At the end my blog is for Engineers and for people, I don’t have interest in bots, and I don’t get any revenue from ads (I never added ads) so I’m perfectly happy with having less visitors, but being humans that find help in the blog.


Why I think in Python is not a good idea to raise exceptions inside your methods

Last update: 2022-05-18 10:48 Irish Time

Recently a colleague was asking me for advice on their design of error handling in a Python application.

They were catching an error and raising an Exception, inside the except part of a method, to be catch outside the method.

And at some point a simple logic got really messy and unnecessarily complicated. Also troubleshooting and debugging an error was painful because they were only getting a Custom Exception and not context.

I explained to my colleague that I believed that the person that created that Exception chain of catch came from Java background and why I think they choose that path, and why I think in Python it’s a bad idea.

In Java, functions and methods can only return one object.

I programmed a lot in Java in my career, and it was a pain having to create value objects, and having to create all kind of objects for the return. Is it a good thing that types are strongly verified by the language? Yes. It worked? Yes. It made me invest much more time than necessary? Also yes.

Having the possibility to return only one object makes it mandatory having a way to return when there was an error. Otherwise you would need to encapsulate an error code and error description fields in each object, which is contrary to the nature of the object.

For example, a class Persona. Doesn’t make any sense having an attribute inside the class Persona to register if an operation related to this object went wrong.

For example, if we are in a class Spaceship that has a method GetPersonaInCommand() and there is a problem in that method, doesn’t make any sense to return an empty Persona object with attributes idError, errorDescription. Probably the Constructor or Persona will require at least a name or Id to build the object…. so in this case, makes sense that the method raises an Exception so the calling code catches it and knows that something went wrong or when there is no data to return.

This will force to write Custom Exceptions, but it’s a solution.

Another solution is creating a generic response object which could be an Object with these attributes:

  • idError
  • errorDescription
  • an Object which is the response, in our example Persona or null

I created this kind of approach for my Cassandra libraries to easily work with Cassandra from Java and from PHP, and for Cassandra Universal Driver (a http/s gateway created in year 2014).

Why this in not necessary in Python

Python allows you to return multiple values, so I encourage you tor return a boolean for indicating the success of the operation, and the object/value you’re interested.

You can see it easily if you take a look to FileUtils class from my OpenSource libraries carleslibs.

The method get_file_size_in_bytes(self, s_file) for example:

    def get_file_size_in_bytes(self, s_file):

        b_success = False
        i_file_size = 0

            # This will help with Unit Testing by raisin IOError Exception

            i_file_size = os.path.getsize(s_file)
            b_success = True
        except IOError:
            b_success = False

        return b_success, i_file_size

It will always return a boolean value to indicate success or failure of the operation and an integer for the size of the file.

The calling code will do something like this:

o_fileutils = FileUtils()
b_success, i_bytes = o_fileutils.get_file_size_in_bytes("profile.png")
if b_succes is False:
    print("Error! The file does not exist or cannot be accessed!")

if i_bytes < 1024:
    print("The profile picture should be at least 1KB")

print("Profile picture exists and is", i_bytes, " bytes in length!")

The fact that Python can return multiple variables makes super easy dealing with error handling without having to take the road of Custom Exceptions.

And it is Ok if you want to follow this path, but in my opinion, for most of the developers up to Senior levels, it only over complicates the logic of your code and the amount of try/excepts you have to have everywhere.

If you use PHP you can mix different types in an Array, so you can always return an Array with a boolean, or an i_id_error, and your object or data of whatever type it’s.

Getting back to my carleslibs Open Source package, it is super easy to Unit Test these methods.

In my opinion, this level of simplicity, brings only advantages. Including Software Development speed, which is good for the business.

I’m not advocating for not using Custom Exceptions or to not develop a Exceptions Raising strategy if you need it and you know what you’re doing. I’m just suggesting why I think most of the developments in Python do not really need this and only over complicates the development. There are situations where raising exceptions will be a perfectly useful or even the best approach, there are many scenarios, but I think that in most of cases, using raise inside except will only multiply the time of the development and slow down the speed of bringing new features to the business, over complicating Unit Test as well, and be a real pain for the Junior and Intermediate developers.

The Constructor

Obviously, as the Constructor doesn’t return any value, it is perfectly fine to raise an exception in there, or just to use try/except in the code that is instancing the objects.