François Scala arcenik

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1. Write a Prometheus exporter in Go

   How to expose Prometheus metrics from a json blob returned by a server.

   Here is a walk through, based on json retreived from an EthSwarm node.

   Retreive the json from EthSwarm status API

   Here is a sample for the status json, from the API documentation,

   {
     "overlay": "36b7efd913ca4cf880b8eeac5093fa27b0825906c600685b6abdd6566e6cfe8f",
     "proximity": 0,
     "beeMode": "light",
     "reserveSize": 0,
     "reserveSizeWithinRadius": 0,
     "pullsyncRate": 0,
     "storageRadius": 0,
     "connectedPeers": 0,
     "neighborhoodSize": 0,
     "requestFailed": true,
     "batchCommitment": 0,
     "isReachable": true,
     "lastSyncedBlock": 0,
     "committedDepth": 0
   }
   

   Prometheus exporter package

   ethswarm/status.go start with the package declaration and imports

2. Docker as Build Environment

   You have a small/mid sized server and you want to install new software or custom kernel on it. But it take forever to build anything on it compared to your brand new 8 or 12 core modern laptop with fast NVMe SSD.

   In addition, you don´t want to pollute your server with all the build dependencies.

   Docker is here to save the day, allowing you to create fast and disposable build environments.

   -rw-r--r-- 1 fs fs 8.6M 2024-12-22 17:33 linux-headers-6.12.6-test_6.12.6-1_amd64.deb
   -rw-r--r-- 1 fs fs  19M 2024-12-22 17:33 linux-image-6.12.6-test_6.12.6-1_amd64.deb
   -rw-r--r-- 1 fs fs 285M 2024-12-22 17:33 linux-image-6.12.6-test-dbg_6.12.6-1_amd64.deb
   -rw-r--r-- 1 fs fs 1.4M 2024-12-22 17:33 linux-libc-dev_6.12.6-1_amd64.deb
   

   Here are two examples with linux kernel image and zfs-linux backport.

3. Shrink Debian Docker Image

   1.8Gb docker image

   As I encountered some ruby problem with Vagrant on my Archlinux laptop, I decided to use Docker as a workaround.

   $ vagrant
   /usr/lib/ruby/3.3.0/rubygems/specification.rb:2245:in `raise_if_conflicts': Unable to activate vagrant_cloud-3.1.1, because rexml-3.3.2 conflicts with rexml (~> 3.2.5) (Gem::ConflictError)
           from /usr/lib/ruby/3.3.0/rubygems/specification.rb:1383:in `activate'
           from /usr/lib/ruby/3.3.0/rubygems/core_ext/kernel_gem.rb:62:in `block in gem'
           from /usr/lib/ruby/3.3.0/rubygems/core_ext/kernel_gem.rb:62:in `synchronize'
           from /usr/lib/ruby/3.3.0/rubygems/core_ext/kernel_gem.rb:62:in `gem'
           from /opt/vagrant/embedded/gems/gems/vagrant-2.4.2/bin/vagrant:17:in `block in <main>'
           from /opt/vagrant/embedded/gems/gems/vagrant-2.4.2/bin/vagrant:16:in `each'
           from /opt/vagrant/embedded/gems/gems/vagrant-2.4.2/bin/vagrant:16:in `<main>'
   

   So let’s create a Docker image, using a debian slim image and just install vagrant and some vagrant plugins.

4. First steps with Bosh on Virtualbox

   Introduction

   BOSH is an open source project from Cloud Foundry that allow release engineering, software deployment and application lifecycle management of large scale and distributed system.

   

   I wanted to take a look at it and fortunately it is possible to play on a local playground environment on VirtualBox using the bosh-lite instruction.