gnt-node: 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 Debian possible default full paths are:

/usr/sbin/gnt-node - from package: ganeti

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

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