So here I explain how to solve a problem that was happening to a friend.
He uses GNS3 for the university, and after installing the latest version, which in this case is 2.2.29, it stopped working.
He had it configured to use the local Server and VirtualBox in Windows 10.
The first thing to check and to fix is the Ip address for Host Only.
If you use Linux or Mac, only certain Ip ranges can be used, or you’ll have to edit a config file inside /etc/vbox
So the first thing is to set an Ip Address in VirtualBox VM that will make you worry free.
So start VirtualBox VM directly, and when the VM boots, use the text menu application to Configure to a valid Ip from the range defined for Host Only.
You can check this in VirtualBox in File > Host Network Manager
In my initial test I picket this Ip for the VM:
192.168.56.100
But using 192.168.56.100 can bring problems as the default DHCP Server is defined with this Ip, so I switched to:
192.168.56.10
Press CTRL + X to save and exit.
The VM will reboot automatically. Wait until it has booted and ping 192.168.56.10 from the Command Prompt.
Now, open a Windows Command Prompt or a Linux/Mac Terminal in you computer and ping the Ip:
You should also be able to see the web interface going to:
http://192.168.56.10
If it works then power off the VM, as we will start it automatically when running GNS3 main program (not from VirtualBox).
Now launch GNS3 program. Wait 30 seconds until it initializes and go to Edit > Preferences
Make sure you have the configuration like this:
Pay special attention to the Port for the GNS3 VM.
It seems like the main problem of my friend was that he was using a previous version, and he updated, and the settings from the previous version were kept. In his previous version he had configured the port 3080, but the new GNS 3 Server version 2.2.29 in the VM was using port 80, as you saw in my previous screenshots. So GNS3 was unable to connect to the VM.
After fixing this, restart GNS3, stop the VM if was not automatically stopped, and start GNS3 again.
After one minute approx connecting, you’ll see it working fine.
I had this idea after one my Python and Linux students with two laptops, a Mac OS X and a Windows one explained me that the Mac OS X is often taken by their daughters, and that the Windows 10 laptop has not enough memory to run PyCharm and Virtual Box fluently. She wanted to have a Linux VM to practice Linux, and do the Bash exercises.
So this article explains how to create a Ubuntu 20.04 LTS Docker Container, and execute a shell were you can practice Linux, Ubuntu, Bash, and you can use it to run Python, Apache, PHP, MySQL… as well, if you want.
You need to install Docker for Windows of for Mac:
Just pay attention to your type of processor: Mac with Intel chip or Mac with apple chip.
The first thing is to create the Dockerfile.
FROM ubuntu:20.04
MAINTAINER Carles Mateo
ARG DEBIAN_FRONTEND=noninteractive
RUN apt update && \
apt install -y vim python3-pip && \
apt install -y net-tools mc htop less strace zip gzip lynx && \
pip3 install pytest && \
apt-get clean
RUN echo "#!/bin/bash\nwhile [ true ]; do sleep 60; done" > /root/loop.sh; chmod +x /root/loop.sh
CMD ["/root/loop.sh"]
So basically the file named Dockerfile contains all the blueprints for our Docker Container to be created.
You see that I all the installs and clean ups in one single line. That’s because Docker generates a layer of virtual disk per each line in the Dockerfile. The layers are persistent, so even if in the next line we delete the temporary files, the space used will not be recovered.
You see also that I generate a Bash file with an infinite loop that sleeps 60 seconds each loop and save it as /root/loop.sh This is the file that later is called with CMD, so basically when the Container is created will execute this infinite loop. Basically we give to the Container a non ending task to prevent it from running, and exiting.
Now that you have the Dockerfile is time to build the Container.
For Mac open a terminal and type this command inside the directory where you have the Dockerfile file:
sudo docker build -t cheap_ubuntu .
I called the image cheap_ubuntu but you can set the name that you prefer.
For Windows 10 open a Command Prompt with Administrative rights and then change directory (cd) to the one that has your Dockerfile file.
docker.exe build -t cheap_ubuntu .
Image being built… (some data has been covered in white)
Now that you have the image built, you can create a Container based on it.
For Mac:
sudo docker run -d --name cheap_ubuntu cheap_ubuntu
For Windows (you can use docker.exe or just docker):
docker.exe run -d --name cheap_ubuntu cheap_ubuntu
Now you have Container named cheap_ubuntu based on the image cheap_ubuntu.
It’s time to execute an interactive shell and be able to play:
sudo docker exec -it cheap_ubuntu /bin/bash
For Windows:
docker.exe exec -it cheap_ubuntu /bin/bash
Our Ubuntu terminal inside Windows
Now you have an interactive shell, as root, to your cheap_ubuntu Ubuntu 20.04 LTS Container.
You’ll not be able to run the graphical interface, but you have a complete Ubuntu to learn to program in Bash and to use Linux from Command Line.
You will exit the interactive Bash session in the container with:
exit
If you want to stop the Container:
sudo docker stop cheap_ubuntu
Or for Windows:
docker.exe stop cheap_ubuntu
If you want to see what Containers are running do:
If that fails is very probably that creating a new configuration, for a new user, will make things right.
Update 2022-01-05: Take in count that you will be copying the Windows registry when doing this. I use this trick to clone applications that are no longer downloadable from the Internet. I clone wine to dedicated Virtual Machines. You may need different Virtual Machines for different programs if windows registry is different for them.
This article talks about how at Riot Games they use Slack. Slack is really a powerful tool, and also makes the communication more human in companies with their approach and the funny icons and /giphy. I’m very serious when it comes to work but I recognize the friendly, warm, human and lovely touch these kind of animated icons bring to the conversations.
Remember that life of the SSD is different from spinning drives. I recommend to keep your backups on external spinning drives disconnected most of the time.
I updated it the Nov-01, as I normally do, bringing more content.
I’ve been paid the royalties for he past two months and I reinvested everything (and more from my pocket) in Hardware for working with ZFS.
I was offered by an editorial in The States to publish Python Combat Guide and other of my books worldwide. I was thinking it for a while. It was very good money, translation to multiple languages and platforms and marketing and a lot of promotion, but I would had loss the rights and the Freedom I have now, like the possibility to offer discount coupons to who I want and to update the contents often. So to celebrate my decision for you, readers of the blog, during September, I provide a discounted price of $5 USD for the fist 100 sales instead of the $25 USD suggested price. Use the following link:
As part of my effort to contributing with nice Open Source products to the Community I have made some investments to keep contributing to:
OpenZFS
My old tool for managing ZFS and Network shares easily
I’m writing a new book about managing ZFS for Small Business too, so I show how to operate on this hardware, good points and downsides.
I’m assembling a new Pc with ZFS plenty of Disk Storage within a mix of:
SAS Enterprise grade SSD 2.5″
SATA 12Gb Enterprise grade SSD 2.5″
SATA SSD 2.5″
SATA HDD 2TB 2.5″
SATA HDD 2TB 3.5″
I’m a big fan of Intel, but this time I have chosen AMD. Concretely a AMD Ryzen 7 3700X AM4 8 Core / 16 Threads, 3.6 GHz to 4.4 GHz with Turbo. The reason I chose this CPU is because it only uses 65W but still has 8 Cores / 16 Threads.
Also I want to see the performance of this AMD Ryzen with CMIPS and another important reason is that AMD motherboards support PCI 4.0. I have bought a NVMe SSD Samsung 980 PRO PCI 4.0 (x4) able to read at 6,400 MB/s. I will use this AMD box for running VMs as well. Basically Virtual Box and Docker.
I’ve been surprised that for 169.99 GBP I can have a very good Asus Motherboard with a 2.5 Gb Ethernet: ASUS ROG STRIX B550-F GAMING, AMD B550, AM4, DDR4, PCIe 4.0, SATA3, Dual M.2, CrossFire, 2.5GbE, USB 3.2 Gen2 A+C, ATX.
In order to have an Asus motherboard with a 2.5 Gb Ethernet for Intel I had to jump to a 254 GBP motherboard and Intel is still PCI 3.0. Actually there are PCI 10Gb NICs at 80 GBP so at some point I’ll upgrade my home network from Gigabit to 10 Gb. That will come slowly, but if the new equipment I assemble has 2.5 Gb when I upgrade the main switches to 10 Gb, at least I’ll be able to communicate at 2.5 Gb without ant additional change.
Also memory at 3200, speed that the AMD motherboard can provide, is more than affordable.
This new server will have 64 GB of RAM (Corsair DDR4 Vengeance PC4-25600 (3200)), as I plan to run VMs and use Volumes mounted via iSCSI and locally as block devices to improve my Software. I’ve bought a new UPS to keep it running in case power goes down. That’s something that doesn’t happen often in my city in Ireland, honestly, but I never forget that this happens in Barcelona two or three times per year, and that a high tension spike can burn your motherboard, drives, or electronics like the TV or the fridge. I’ve bought as well a new KVM Switch, a HDMI 4K and USB too one, so I don’t have to have so many keyboards. My logitech M720 allowed me to use it with 3 computers, but still I want something more operational. The KVM I bought allow me to switch with a button or within a hotkey in the keyboard.
I bought a new Icy box fox handling 6 2.5 drives in just one bay of the tower, and a 850 Watt Corsair PSU that will be able to power the many drives I want at the same time.
ZFS on Ubuntu 20.04.1 LTS A guide for Small/Medium Business and power users to work with ZFS. https://leanpub.com/zfs-ubuntu
Those can be purchased while I’m still working on them and get the updates that I’ll be publishing and keeping a communication with me about doubts or improvements.
Halloween Software Offers
I saw some Halloween offers and I purchased Software licenses for Software I use.
I contribute a lot to Open Source, and many years ago before Open Source existed I was creating Freeware Software. But I think that good commercial Software deserves to be supported. Like everything in life, if they are doing a good work that is useful to me, why not giving them support?. It is also a way to make sure they will continue producing amazing Software. And in the other hand, myself, I create Software. Some times commercial Software, and I like to be paid, so I apply the same principle.
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.
I studied the evolution of several countries and I was working with simulations in Spain until their government started blocking the information and stop providing transparent and accurate metrics.
I’m seeing how the covid is affecting and transforming several kind of business:
Meetup.com I see meetups with more than 1,000 users closing, as they are no meeting anymore
Airlines, obviously
Hotels, offering less services
Metasearchers and OTAs (Online travel agencies)
I can imagine the impact on airbnb
Discos, nightclubs are closing doors
Restaurants, they will lose the Christmas season (with families and companies doing lunch and dinners)
At the same time, other companies are hitting records in sales
Videogames companies
Hardware is being sold, to accommodate WFH and remote working.
Companies like Amazon or Overstock.com are delivering well where people before were buying into stores.
VPN solutions for Remote Working are being implemented in those places that had not enabled Remote Working.
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.
1- Make sure the zfs file exists under zfs/contrib/initramfs/scripts/local-top/
if not exists, create a file called zfs under zfs/contrib/initramfs/scripts/local-top/ and add the following to that file:
#!/bin/sh PREREQ=”mdadm mdrun multipath”
prereqs() { echo “$PREREQ” }
case $1 in # get pre-requisites prereqs) prereqs exit 0 ;; esac
# # Helper functions # message() { if [ -x /bin/plymouth ] && plymouth –ping; then plymouth message –text=”$@” else echo “$@” >&2 fi return 0 }
udev_settle() { # Wait for udev to be ready, see https://launchpad.net/bugs/85640 if [ -x /sbin/udevadm ]; then /sbin/udevadm settle –timeout=30 elif [ -x /sbin/udevsettle ]; then /sbin/udevsettle –timeout=30 fi return 0 }
activate_vg() { # Sanity checks if [ ! -x /sbin/lvm ]; then [ “$quiet” != “y” ] && message “lvm is not available” return 1 fi
# Detect and activate available volume groups /sbin/lvm vgscan /sbin/lvm vgchange -a y –sysinit return $? }
