chronyc is looking for the /etc/chrony.conf which does not exist
The chronyc is looking for the /etc/crony.conf when running interactive. See below for the error and strace.
$ sudo chronyc -a activity
Could not open file /etc/chrony.conf : No such file or directory
$ sudo strace chronyc -a activity
execve("/usr/bin/chronyc", ["chronyc", "-a", "activity"], [/* 13 vars */]) = 0
arch_prctl(ARCH_SET_FS, 0x68233213f048) = 0
set_tid_address(0x68233213f080) = 22871
mprotect(0x68233213d000, 4096, PROT_READ) = 0
mprotect(0xbae6bfa7000, 4096, PROT_READ) = 0
ioctl(0, TIOCGWINSZ, {ws_row=50, ws_col=150, ws_xpixel=0, ws_ypixel=0}) = 0
ioctl(1, TIOCGWINSZ, {ws_row=50, ws_col=150, ws_xpixel=0, ws_ypixel=0}) = 0
ioctl(2, TIOCGWINSZ, {ws_row=50, ws_col=150, ws_xpixel=0, ws_ypixel=0}) = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
setsockopt(3, SOL_IP, IP_RECVERR, [1], 4) = 0
open("/etc/chrony.conf", O_RDONLY) = -1 ENOENT (No such file or directory)
writev(2, [{"Could not open file /etc/chrony."..., 65}, {NULL, 0}], 2Could not open file /etc/chrony.conf : No such file or directory
) = 65
close(3) = 0
exit_group(1) = ?
+++ exited with 1 +++
$
$ cat /etc/alpine-release
3.2.3
$ apk info --who-owns /usr/bin/chronyc
/usr/bin/chronyc is owned by chrony-2.0-r0
$
There is however the /etc/chrony/chrony.conf which is delivered with chrony packages. https://pkgs.alpinelinux.org/contents?pkgname=chrony&arch=x86\_64&repo=main
(from redmine: issue id 4774, created on 2015-10-18)