ceilometer-agent-notification: command not found

Have You tried accessing the binary with the full path?

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/ceilometer-agent-notification - from package: ceilometer-agent-notification

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