From what I have observed, `ha.pool.sks-keyservers.net` is not very reliable and I have failed to receive keys on several occasions. I think we should add alternative mirrors, something like: ``` RUN set -ex; \ for key in $GPG_KEYS; do \ gpg --keyserver pgp.mit.edu --recv-keys "$key" || \ gpg --keyserver keyserver.pgp.com --recv-keys "$key" || \ gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key" ; \ done ```