ssh-keygen in alpine:3.6

$ docker run -it alpine:3.6
/ # which ssh-keygen
/ # apk update
fetch http://dl-cdn.alpinelinux.org/alpine/v3.6/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.6/community/x86_64/APKINDEX.tar.gz
v3.6.2-287-g715507dc62 [http://dl-cdn.alpinelinux.org/alpine/v3.6/main]
v3.6.2-277-g4c7d815e52 [http://dl-cdn.alpinelinux.org/alpine/v3.6/community]
OK: 8437 distinct packages available
/ # apk add --no-cache openssh-keygen
fetch http://dl-cdn.alpinelinux.org/alpine/v3.6/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.6/community/x86_64/APKINDEX.tar.gz
(1/1) Installing openssh-keygen (7.5_p1-r2)
Executing busybox-1.26.2-r9.trigger
OK: 4 MiB in 12 packages
/ # which ssh-keygen
/usr/bin/ssh-keygen
/ #