Below you have few ways to create small consul clusters that will do nothing, just to show you how they can be made to connect to each other.

Useful things to work with

Here you have just small docker tricks to be able to see what consul is doing and what is exposing.

View container's logs by having them shown as they come, starting with the last 10 lines:

docker logs -f --tail 10 CONTAINER_NAME

root@uranus:~# docker logs -f --tail 10 c4
    2019/04/11 21:12:55 [DEBUG] memberlist: Stream connection from=192.168.11.28:44010
    2019/04/11 21

You know how to pull and create custom images; do whatever with them. But if you need the same custom image on multiple servers in your network, you will have to copy that image on them. Here comes docker registry: a local repository of your images. And the installation of a local repository is done via (guess?) a container :). Basically, all you have to do is to pull the registry image and run a container on top of it.

In this tutorial, I will show you how to create a custom docker image and run a container on top of it.

1.

So I finally got a bit into docker because everybody is talking about it. I will skip the installation part because it is not that difficult (easier than windows install actually: next, next, finish) and go straight to the interesting part: using docker commands.

By default (relying on my tests only), docker is creating containers on top of:

- windows - hyper-v - macos - hyperkit - linux - mnt namespace (a fancy chroot :) This can differ, depending on docker versi

I recently upgraded the debian version from 8 to 9 and my surprise was to not being able to connect to the newly upgraded server with my usual ssh key. It turns out that beyond OpenSSH version 6.6, the "unsafe algorithms" have been removed, including my kinda old dss key. All you have to do is to create a new one. I choose ecdsa:

$ ssh-keygen -t ecdsa

Do not forget to put the newly pub key (e.g. the content of ~/.ssh/id_ecdsa.pub) in ~/.ssh/authorized_keys of the upgraded server. Well, that was kinda short. Enjoy! :)

Got the following error when attempting to upgrade outdated via port upgrade outdated:

--->  Fetching distfiles for librsvg
--->  librsvg-2.44.13.tar.xz does not exist in /opt/local/var/macports/distfiles/librsvg
--->  Attempting to fetch librsvg-2.44.13.tar.xz from https://distfiles.macports.org/librsvg
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 12.0M  100 12.0M    0     0  1316k      0  0:00:09  0:00:09 --:--:-- 1651k
[...

How to remove the contents from a File:

Note: this does not removes the file. It only clears the content, which is very useful if you want to clear a log on which an application writes continuously.

Almost all operating system have command line commands. They are always there, even if we do not know about them. Actually, the GUI programs that provide us ways to do things, like Disk Util for example, are just a graphical wrap over the command line tool. And they do not provide all the features. Today, I will show you how to update your MacOS via command line. Benefits: you only need to restart once and the first phase of the installation can be done while you do your stuff so no need to wait for the progress bar to fill up and then reboot.

1.

The error I got today was related to speedtest-cli:

florians-MacBook-Pro$ speedtest
Traceback (most recent call last):
  File "/opt/local/bin/speedtest", line 6, in <module>
    from pkg_resources import load_entry_point
ModuleNotFoundError: No module named 'pkg_resources'

The macports package speedtest-cli is a terminal port for the popular speedtest.net. The source is available here. I truly do not know after which modification/upgrade I got this error because I do not use this utility often.

You have upgraded to macOS High Sierra and found this error while trying to upgrade macports via command line?

fmbp:~ florian$ sudo port -v selfupdate
Error: Current platform "darwin 17" does not match expected platform "darwin 16"
Error: If you upgraded your OS, please follow the migration instructions: https://trac.macports.org/wiki/Migration
OS platform mismatch
    while executing
"mportinit ui_options global_options global_variations"
Error: /opt/local/bin/port: Failed to initialize MacPorts, OS platform mismatch

The error is explaining very well what i