root@ip-172-31-102-135:/var/lib/juju/agents/unit-collectd-1/charm# apt update 
Hit:1 http://us-west-2.ec2.archive.ubuntu.com/ubuntu xenial InRelease
Hit:2 http://us-west-2.ec2.archive.ubuntu.com/ubuntu xenial-updates InRelease                          
Hit:3 http://us-west-2.ec2.archive.ubuntu.com/ubuntu xenial-backports InRelease                                     
Get:4 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]                                          
Ign:5 http://ppa.launchpad.net/peopledatalabs/ppa/ubuntu xenial InRelease                                           
Err:6 http://ppa.launchpad.net/peopledatalabs/ppa/ubuntu xenial Release                                             
  404  Not Found
Ign:7 http://pkg.ci.collectd.org/deb xenial InRelease                                            
Hit:8 http://pkg.ci.collectd.org/deb xenial Release  
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/peopledatalabs/ppa/ubuntu xenial Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.