keystone-manage: 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/bin/keystone-manage - from package: keystone

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

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