Ubuntu unable to locate package

Question

I have installed devstack for openstack on ubuntu system. I am trying to install quantum-lbaas-agent. I get the error Unable to locate package. I tried

Answer 1

My problem

kuma-soft@kumasoft-Inspiron-15-3567:~$ sudo apt install virtualenv
[sudo] password for kuma-soft: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package virtualenv
kuma-soft@kumasoft-Inspiron-15-3567:~$ sudo apt install simplescreenrecorder
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package simplescreenrecorder

sudo apt-get update

Y