To Reproduce
Install the latest do-agent from yum repository. Run journalctl -f to watch systemd logging in real time. From another shell run systemctl restart do-agent
You will see the following error in the journalctl shell:
Failed at step EXEC spawning /opt/digitalocean/bin/do-agent --syslog: Permission denied
To Fix
chmod 755 /opt/digitalocean
chmod 755 /opt/digitalocean/bin
Run systemctl restart do-agent again and it should work now