[CentOS] Network services start before network is up since migrating to 7.2

[Gordon Messmer]

On 12/17/2015 07:59 AM, Sylvain CANOINE wrote:
>> Well it looks like you are using the network service rather than the
>> recommended NetworkManager ...
> Yes. That's the way our security experts made the models I use to setup my servers.
> I'll test a migration to NetworkManager, and take their advice on it.

Note that the behavior you're seeing is documented:
http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/

If you're using NetworkManager, you can "systemctl enable 
NetworkManager-wait-online.service" and you won't have to override any 
of the individual services.

>> The network service is not blocking  the flow so it executes and systemd
>> carries on ...
>>
>>  From the point of view of the system as soon as /etc/init.d/network start
>> has been called the service is running as a state... as you can see from
>> your logs lots of other services also start before the network interface
>> itself is up.
> I understand this, but why only on one of my servers ? Is the order the services start only a question of latencies ?

Basically, yes.

>
>> Incidentally I just tried a quick test in a VM and it would appear
>> NetworkManager.service completed with an IP on the network interface before
>> network.target was considered reached ... you may want to test this on your
>> system to see if it's a race condition

It is, as documented above.