Raspberry, Ubuntu and Megatools

Posted on 17 June 2020 by kosmas

To install megtools (command line utilities for Mega.nz), in your raspberry with ubuntu installed follow the steps below (thanks to the instructions from here: https://www.instructables.com/id/Descarga-archivos-de-Mega-con-Raspberry-Pi/)

Install the necessary packages

sudo apt-get -y install build-essential libglib2.0-dev libssl-dev libcurl4-openssl-dev libgirepository1.0-dev 

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						sudo apt-get -y install build-essential libglib2.0-dev libssl-dev libcurl4-openssl-dev libgirepository1.0-dev

You may also need to add some additional packages if there is an error about the documentation.

Get the latest source code from https://megatools.megous.com

wget https://megatools.megous.com/builds/megatools-1.10.3.tar.gz

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						wget https://megatools.megous.com/builds/megatools-1.10.3.tar.gz

Compile and install them

tar xvfz megatools-1.10.3.tar.gz
cd megatools-1.10.3
./configure
make
sudo make install
sudo ldconfig

				
					
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						tar xvfz megatools-1.10.3.tar.gz
cd megatools-1.10.3
./configure
make
sudo make install
sudo ldconfig

					

			

Add your Mega account credentials in ~/.megarc like:

[Login]
Username = my_mega@email
Password = mypassword

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						[Login]
Username = my_mega@email
Password = mypassword

use the mega tools commands (megacopy, megals, megaget etc.

Erlang and Elixir with asdf in Raspberry 4 with Ubuntu 20.04

Posted on 12 June 2020 by kosmas

To install the latest/current versions of erlang (23.0.2) and elixir (1.10.3), follow the instructions below:

Install asdf ( full instructions https://asdf-vm.com/#/core-manage-asdf-vm):

git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch v0.7.8

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						git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch v0.7.8

Add the following two lines in your ~/.bashrc file:

# Add asdf version manager 
. $HOME/.asdf/asdf.sh
. $HOME/.asdf/completions/asdf.bash

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						# Add asdf version manager 
. $HOME/.asdf/asdf.sh
. $HOME/.asdf/completions/asdf.bash

Reload/Source your bash file with

source ~/.bashrc

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						source ~/.bashrc

Install the erlang plugin

asdf plugin add erlang

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						asdf plugin add erlang

If you get the following warnings:

...
Extracting source code
Building Erlang/OTP 23.0.2 (asdf_23.0.2), please wait...
WARNING: It appears that a required development package 'libssl-dev' is not installed.
WARNING: It appears that a required development package 'automake' is not installed.
WARNING: It appears that a required development package 'autoconf' is not installed.
WARNING: It appears that a required development package 'libncurses5-dev' is not installed.
Configure failed.
...

				
					
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						...
Extracting source code
Building Erlang/OTP 23.0.2 (asdf_23.0.2), please wait...
WARNING: It appears that a required development package 'libssl-dev' is not installed.
WARNING: It appears that a required development package 'automake' is not installed.
WARNING: It appears that a required development package 'autoconf' is not installed.
WARNING: It appears that a required development package 'libncurses5-dev' is not installed.
Configure failed.
...

					

			

Install the missing packages:

sudo apt install libssl-dev automake autoconf libncurses5-dev

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						sudo apt install libssl-dev automake autoconf libncurses5-dev

Install latest erlang version:

asdf install erlang latest
...
Erlang/OTP 23.0.2 (asdf_23.0.2) has been successfully built
...

				
					
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						asdf install erlang latest
...
Erlang/OTP 23.0.2 (asdf_23.0.2) has been successfully built
...

					

			

Set it up globally (if you want):

asdf global erlang 23.0.2

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						asdf global erlang 23.0.2

Add elixir plugin:

asdf plugin add elixir

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						asdf plugin add elixir

Install latest elixir version (1.10.3):

asdf install elixir latest

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						asdf install elixir latest

Set it up globally:

asdf global elixir 1.10.3-otp-23

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						asdf global elixir 1.10.3-otp-23

Finally you can also install the latest Phoenix version (1.5.3):

mix archive.install hex phx_new 1.5.3

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						mix archive.install hex phx_new 1.5.3

WiFi, Raspberry Pi 4 B, Ubuntu 20.04

Posted on 10 June 2020 by kosmas

After installing an image of the Ubuntu server on the Raspberry 4, the wifi is not automatically configured after the initial book.

In order to be able to use the WiFi follow the steps described below for setting up your wifi in your SD card, and then reboot your raspberry (make sure that the indentation in the yaml file is correct, and also your WiFi access point is enclosed in quotes):

https://ubuntu.com/tutorials/how-to-install-ubuntu-on-your-raspberry-pi#3-wifi-or-ethernet

restarting X Window Server from command line in linux

Posted on 2 June 2020 by kosmas

To restart your X Window Server from the command line in linux, without affecting any non-graphical programs (but losing any unsaved information in your graphical user interface programs), you can use the following:

sudo systemctl restart display-manager

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						sudo systemctl restart display-manager

sudo kubeadmin init returns with: [ERROR Swap]: running with swap on is not supported. Please disable swap

Posted on 26 May 2020 by kosmas

Problem

You are trying to set up kubernetes on your local machine but trying to use initialize it with kubeadmin init, returns the following error:

[init] Using Kubernetes version: v1.18.3
[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR Swap]: running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

				
					
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						[init] Using Kubernetes version: v1.18.3
[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR Swap]: running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

					

			

Solution

Switch the swap to off (Ubuntu command below) and try again.

sudo swapoff -a

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						sudo swapoff -a

Setting up worldPing with Grafana running in docker

Posted on 15 May 2020 by kosmas

You would like to test worldPing (https://worldping.raintank.io/worldping/) in your local environment for evaluation purposes.

Install Grafana with docker as described here (https://grafana.com/docs/grafana/latest/installation/docker/) and give it a name (ie grafana)
Login to the grafana container and install the worldPing plugin:

$ docker exec -it grafana /bin/bash
bash-5.0$ grafana-cli plugins install raintank-worldping-app

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						$ docker exec -it grafana /bin/bash
bash-5.0$ grafana-cli plugins install raintank-worldping-app

Exit from the container and stop and start it

bash-5.0$ exit
$ docker stop grafana
$ docker start grafana

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						bash-5.0$ exit
$ docker stop grafana
$ docker start grafana

Login to your grafana installation on the browser (localhost:3000) and go to the section for the plugins to find worldPing
To be able to enable it you will need an API key from Grafana Cloud, so create a free account (https://grafana.com/signup/starter/connect-account)
Create an API key (Security – API Keys – Add API Key)
Go back to Grafana web UI and add the API key so you can enable the worldPing. Add an endpoint to check and select the services to check (DNS, Ping, HTTP, HTTPS)
Leave it running for a few minutes and check the dashboards afterwards.
Remember to Disable if you want to go back to it again in the near future, or Destroy the endpoint if you do not need it anymore.

ssh-add, Gitlab CI/CD with alpine image

Posted on 27 April 2020 by kosmas

Problem

Trying to use the usual way of adding Gitlab’s key to the ssh agent, is not working in alpine image (but it works in debian/ubuntu), and you get the following error message:

 - ssh-add <(echo "$GITLABCICD_PRIVATE_KEY")
/bin/sh: syntax error: unexpected "("

Solution

Try to use the following instead:

  - echo "$GITLABCICD_PRIVATE_KEY" | ssh-add -

AWS allowing access to Billing to IAM user

Posted on 17 April 2020 by kosmas

Problem

When you create a new AWS account the access to Billing for IAM users is not enabled by default.

Solution

In order to allow access you have to follow the steps below:

Login to your AWS account with your root user (email and password)
Go to the top right drop down ‘My Account’
Find the section that is called ‘IAM User and Role Access to Billing information’, use ‘Edit’, tick the box ‘Enable access’ and then ‘Update’.

More information can be found in the Amazon’s help page https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/control-access-billing.html#ControllingAccessWebsite-Activate

Get a list of your Route53 subdomains using aws cli docker image

Posted on 13 March 2020 by kosmas

Problem

You would like to have a list of your subdomains for a specific domain (hosted zone), that are hosted in Amazon’s Route 53.

Solution

You can install the aws cli docker image from here https://github.com/cgswong/docker-aws if you don’t want to install the aws cli in your computer.

You can afterwards start the container with:

docker run -it cgswong/aws:latest

Then configure it by running the following and adding your credentials and zone:

efe9881d4fd:/tmp# aws configure
 AWS Access Key ID [None]: aws_access_key_id
 AWS Secret Access Key [None]: aws_secret_access_key
 Default region name [None]: eu-central-1
 Default output format [None]:

Then run the first command to get a list of the hosted zones and get the id of the hosted zone you want to find the subdomains for:

3efe9881d4fd:/tmp# aws route53 list-hosted-zones
{
    "HostedZones": [
        {
            "ResourceRecordSetCount": 2, 
            "CallerReference": "RISWorkflow-RD:xxxxx", 
            "Config": {
                "Comment": "HostedZone created by Route53 Registrar", 
                "PrivateZone": false
            }, 
            "Id": "/hostedzone/HOSTEDZONEID", 
            "Name": "domain.net."
        },

Then pick the HOSTEDZONEID and run the following to get a list of subdomains for that domain:

3efe9881d4fd:/tmp# aws route53 list-resource-record-sets --hosted-zone="HOSTEDZONEID" | grep "Name" | uniq

   "Name": "alpah.domain.com.",                                                                                                                                                                                                                                             
   "Name": "beta.domain.com.",                                                                                                                                                                                                                                       
   "Name": "lamda.domain.com.",
......

Find devices with their IPs in your local network

Posted on 10 March 2020 by kosmas

Problem

You would like to have a list of IPs or MAC address for the device in your network

Solution

Use the ARP protocol’s command:

$ arp -a

dv1.home (192.168.1.102) at 48:xx:xx:xx:xx:xx [ether] on wlp4s0
dv2.home (192.168.1.127) at a4:xx:xx:xx:xx:xx [ether] on wlp4s0
...

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Web notebook about thoughts and discoveries in DevOps, SRE, Software Engineering….

Raspberry, Ubuntu and Megatools

Erlang and Elixir with asdf in Raspberry 4 with Ubuntu 20.04

WiFi, Raspberry Pi 4 B, Ubuntu 20.04

restarting X Window Server from command line in linux

sudo kubeadmin init returns with: [ERROR Swap]: running with swap on is not supported. Please disable swap

Problem

Solution

Setting up worldPing with Grafana running in docker

ssh-add, Gitlab CI/CD with alpine image

Problem

Solution

AWS allowing access to Billing to IAM user

Problem

Solution

Get a list of your Route53 subdomains using aws cli docker image

Problem

Solution

Find devices with their IPs in your local network

Problem

Solution