use proxy plugin of CoreDNS

Before post, please see try to use CoreDNS - AKAI TSUKI

I configure Corefile to use proxy.
ref. https://coredns.io/plugins/proxy/

[root@cent7devops ~]# cat Corefile
. {
    proxy . 8.8.8.8:53
    errors
    log
}
[root@cent7devops ~]#

I need to send "SIGUSR1(10)" to CoreDNS, when CoreDNS reload Corefile.
ref. https://coredns.io/plugins/reload/
When I sent "SIGHUP(1)", CoreDNS didn't reload Corefile.
Though the web page in the above url described "SIGHUP" or "SIGUSR1".

[root@cent7devops ~]# ps -aef | grep coredns
root      5664  1291  0 01:49 pts/0    00:00:00 coredns -conf Corefile
root      5743  2239  0 01:58 pts/2    00:00:00 grep --color=auto coredns
[root@cent7devops ~]#
[root@cent7devops ~]# kill -10 5664

When CoreDNS reload configuration file, it output the following log.

2018/07/13 02:04:37 [INFO] SIGUSR1: Reloading
2018/07/13 02:04:37 [INFO] Reloading
2018/07/13 02:04:37 [INFO] Reloading complete

Then, I execute the following command.
I can get ipaddress to "akai-tsuki.hatenablog.com" by proxy (8.8.8.8 dns server).

[root@cent7devops ~]# dig -p 53 @localhost A akai-tsuki.hatenablog.com +noall +answer

; <<>> DiG 9.9.4-RedHat-9.9.4-61.el7 <<>> -p 53 @localhost A akai-tsuki.hatenablog.com +noall +answer
; (2 servers found)
;; global options: +cmd
akai-tsuki.hatenablog.com. 59   IN      A       13.230.115.161
akai-tsuki.hatenablog.com. 59   IN      A       13.115.18.61
[root@cent7devops ~]#

This is log of above command execution.

[::1]:48264 - [13/Jul/2018:02:05:21 +0900] 63209 "A IN akai-tsuki.hatenablog.com. udp 55 false 4096" NOERROR qr,rd,ra 137 0.170752488s