sss_override: 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

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/sss_override - from package: sssd-tools

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