cman_notify: 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 CentOS possible default full paths are:

/usr/sbin/cman_notify - from package: cman

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

On Debian possible default full paths are:

/usr/sbin/cman_notify - from package: cman

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