euscale-set-instance-health: 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/euscale-set-instance-health - from package: euca2ools

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

On Debian possible default full paths are:

/usr/bin/euscale-set-instance-health - from package: euca2ools

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

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