cimgイメージを利用しているときGPG Keyのエラーが発生するとき
code:bash
sudo apt update && sudo apt install -y rsync
100% WorkingReading package lists... Done W: GPG error: http://archive.debian.org/debian jessie Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8B48AD6246925553 NO_PUBKEY 7638D0442B90D010 NO_PUBKEY CBF8D6FD518E17E1 N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
Exited with code exit status 100
CircleCI received exit code 100
こんな感じで特定のキーが利用できないエラーが発生するので追加してやる
code:bash
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9D6D8F6BC857C906 AA8E81B4331F7F50 #ここにkeyを