cloud-init: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/cloud-init - from package: cloud-init

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/cloud-init - from package: cloud-init

You may install the required package with command apt-get install {package}

Error in other languages:
cloud-init: bevel nie gevind nie
cloud-init: comandă negăsită
cloud-init: comando não encontrado
cloud-init: commande introuvable
cloud-init: command not found
cloud-init: käsku ei ole
cloud-init: không tìm thấy lệnh
cloud-init: komanda nerasta
cloud-init: Kommando nicht gefunden.
cloud-init: kommandot finns inte
cloud-init: komut yok
cloud-init: nie znaleziono polecenia
cloud-init: níor aimsíodh an t-ordú
cloud-init: no se encontró la orden
cloud-init: no s'ha trobat l'ordre
cloud-init: opdracht niet gevonden
cloud-init: parancs nem található
cloud-init: perintah tidak ditemukan
cloud-init: príkaz nenájdený
cloud-init: příkaz nenalezen
cloud-init: команда не найдена
cloud-init: командата не е открита
cloud-init: 命令找不到
cloud-init: コマンドが見つかりません