fence_sanlockd: 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_sanlockd - from package: fence-sanlock

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

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