ovs-pki: 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 Debian possible default full paths are:

/usr/bin/ovs-pki - from package: openvswitch-common

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

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