mysqlfailover: 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/mysqlfailover - from package: mysql-utilities

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

On Debian possible default full paths are:

/usr/bin/mysqlfailover - from package: mysql-utilities

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

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