ctdb_run_cluster_tests: 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/bin/ctdb_run_cluster_tests - from package: ctdb-tests

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