asdf and terraform (or vault or packer)

Posted on 7 April 2021 by kosmas

Using the asdf version manager to manage versions of various binaries like terraform, vault or packer is easily done by following the instructions below:

Download and install asdf if you haven’t got it already (https://asdf-vm.com/#/core-manage-asdf)
If you want to install the latest version of terraform for example do the following:

asdf plugin add terraform
asdf install terraform latest
asdf global terraform 0.14.9
asdf list
terraform
  0.14.9
terraform --version
Terraform v0.14.9

				
					
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						asdf plugin add terraform
asdf install terraform latest
asdf global terraform 0.14.9
asdf list
terraform
  0.14.9
terraform --version
Terraform v0.14.9

					

			

Get/Set platform information

Posted on 15 March 2021 by kosmas

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To get or set in environment variables the platform information of a system you can use the following:

export ARCH=$(case $(arch) in x86_64) echo -n amd64 ;; aarch64) echo -n arm64 ;; *) echo -n $(arch) ;; esac)
export OS=$(uname | awk '{print tolower($0)}')

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						export ARCH=$(case $(arch) in x86_64) echo -n amd64 ;; aarch64) echo -n arm64 ;; *) echo -n $(arch) ;; esac)
export OS=$(uname | awk '{print tolower($0)}')

Taken from the installation instructions of the Operator SKD here: https://master.sdk.operatorframework.io/docs/installation/

Linux disabling a service on bootup

Posted on 12 February 2021 by kosmas

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To stop having a service automatically start after bootup in a Linux system with systemctl use the following to stop and then disable the service:

sudo systemctl stop service_name
sudo systemctl disable service_name

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						sudo systemctl stop service_name
sudo systemctl disable service_name

Failed to start docker.service: Unit is masked

Posted on 27 January 2021 by kosmas

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Problem

Trying to start the docker service after some upgrades fails with the following message:

Failed to start docker.service: Unit is masked.

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						Failed to start docker.service: Unit is masked.

Solution

It turns out that after upgrading or more specifically removing and then upgrading the docker installation in ubuntu (in this particular case in raspberry 4 with Ubuntu 20.04 installed), results in this error.

A search brings up the following:

https://forums.docker.com/t/failed-to-start-docker-service-unit-is-masked/67413

and from that the following bug post:

https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1844894

So the solution is to run the following to be able to start the docker service (described in the first link above):

sudo systemctl unmask docker
sudo systemctl start docker

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						sudo systemctl unmask docker
sudo systemctl start docker

Getting detailed information about your Linux distribution

Posted on 16 December 2020 by kosmas

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To be able to get a more detailed information about your current linux distribution, including the code names use the following:

kosmas:$ cat /etc/os-release
NAME=&quot;Ubuntu&quot;
VERSION=&quot;18.04.5 LTS (Bionic Beaver)&quot;
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME=&quot;Ubuntu 18.04.5 LTS&quot;
VERSION_ID=&quot;18.04&quot;
HOME_URL=&quot;https://www.ubuntu.com/&quot;
SUPPORT_URL=&quot;https://help.ubuntu.com/&quot;
BUG_REPORT_URL=&quot;https://bugs.launchpad.net/ubuntu/&quot;
PRIVACY_POLICY_URL=&quot;https://www.ubuntu.com/legal/terms-and-policies/privacy-policy&quot;
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

				
					
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						kosmas:$ cat /etc/os-release
NAME=&quot;Ubuntu&quot;
VERSION=&quot;18.04.5 LTS (Bionic Beaver)&quot;
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME=&quot;Ubuntu 18.04.5 LTS&quot;
VERSION_ID=&quot;18.04&quot;
HOME_URL=&quot;https://www.ubuntu.com/&quot;
SUPPORT_URL=&quot;https://help.ubuntu.com/&quot;
BUG_REPORT_URL=&quot;https://bugs.launchpad.net/ubuntu/&quot;
PRIVACY_POLICY_URL=&quot;https://www.ubuntu.com/legal/terms-and-policies/privacy-policy&quot;
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

					

			

Displaying timestamps in dmesg output

Posted on 10 December 2020 by kosmas

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If you would like to be able to see the dmesg output with timestamps instead of time in seconds since booting up, use the -T like:

dmesg -T | less

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						dmesg -T | less

Brennan B2 ssh login

Posted on 18 November 2020 by kosmas

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Problem

You would like to login to your Brennan B2 using your ssh key.

Solution

Copy your public ssh key to /root/.ssh/authorized_keys file in your Brennan B2

SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch

Posted on 23 September 2020 by kosmas

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Problem

Trying to configure and use an nginx server that uses intermediate certifcates, you get the error about values mismatch and nginx does not start

2020/09/23 09:49:38 [emerg] 20958#20958: SSL_CTX_use_PrivateKey(&quot;/etc/ssl/private/cakey.pem&quot;) failed (SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch)

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						2020/09/23 09:49:38 [emerg] 20958#20958: SSL_CTX_use_PrivateKey(&quot;/etc/ssl/private/cakey.pem&quot;) failed (SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch)

Solution

It seems that this is a common mistake and it is mentioned here: https://nginx.org/en/docs/http/configuring_https_servers.html. In order to fix this you will need to change/reverse the original order that you have concatenated the chain, as in:

cat certs/cacert.pem intermediate/certs/intermediate.cacert.pem &gt; intermediate/certs/ca-chain-bundle.cert_new.pem

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						cat certs/cacert.pem intermediate/certs/intermediate.cacert.pem &gt; intermediate/certs/ca-chain-bundle.cert_new.pem

Decode access secret key from Terraform IAM user creation

Posted on 8 September 2020 by kosmas

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Problem

You want to use the pgp encryption when using Terraform to create an AWS IAM user, and you have the secret access token returned as an output but encoded.

Solution

Use the following to get the actual secret key decoded (after copying your encoded key to a file encrypted_key.txt:

$ cat encrypted_key.txt | base64 --decode | gpg -d

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						$ cat encrypted_key.txt | base64 --decode | gpg -d

Raspberry, Ubuntu and Megatools

Posted on 17 June 2020 by kosmas

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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.

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

Category Archives: Bash

asdf and terraform (or vault or packer)

Get/Set platform information

Linux disabling a service on bootup

Failed to start docker.service: Unit is masked

Problem

Solution

Getting detailed information about your Linux distribution

Displaying timestamps in dmesg output

Brennan B2 ssh login

Problem

Solution

SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch

Problem

Solution

Decode access secret key from Terraform IAM user creation

Raspberry, Ubuntu and Megatools