fence_virt: 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/sbin/fence_virt - from package: fence-virt

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

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