fix: add a delay between starting Netdata and checking pids

[ilyam8]

Summary

The delay is needed on slow servers, that is what I get on my DO droplet (Basic plan):

Stopping all netdata threads
[/home/ilyam/netdata]# stop_all_netdata
 OK

Starting netdata using command 'systemctl start netdata'
[/home/ilyam/netdata]# systemctl start netdata
 OK

Ooops! it seems netdata is not started.
Attempting another netdata start using command 'systemctl start netdata'
[/home/ilyam/netdata]# systemctl start netdata
 OK

Hm... it seems netdata is still not started.
Netdata service still not started, attempting another forced restart by running '/opt/netdata/usr/sbin/netdata '
[/home/ilyam/netdata]# stop_all_netdata
 OK

[/home/ilyam/netdata]# /opt/netdata/usr/sbin/netdata
 OK

 OK  netdata started!

The reason is:

• systemctl start netdata returns as soon as "netdata.service" cgroup created.
• Netdata is not started by this moment (ExecStart directive hasn't been executed (or at least completed)).

The end result is:

• I got running Netdata.
• but it is not controlled by systemd (systemd netdata unit is failed, I have to kill -9 netdata process).

---

I didn't find a way to delay systemctl start <service> returning.

Test Plan

Install Netdata, ensure Netdata is started by systemd and not manually by the script.

installer log after the patch

 --- Restarting netdata instance ---

Stopping all netdata threads
[/home/ilyam/src/nd_ilyam8]# stop_all_netdata
 OK

Starting netdata using command 'systemctl start netdata'
[/home/ilyam/src/nd_ilyam8]# systemctl start netdata
 OK

 OK  netdata started!

[/home/ilyam/src/nd_ilyam8]# chmod 0644 /opt/netdata/etc/netdata/netdata.conf
 OK

Additional Information