Error when adding repo to install kubectl
jonas@octo:~$ sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main" Hit:1 http://jp.archive.ubuntu.com/ubuntu bionic InRelease Get:2 https://nvidia.github.io/libnvidia-container/ubuntu18.04/amd64 InRelease [1,106 B] Get:3 https://nvidia.github.io/nvidia-container-runtime/ubuntu18.04/amd64 InRelease [1,103 B] Hit:4 http://jp.archive.ubuntu.com/ubuntu bionic-updates InRelease Hit:5 https://download.docker.com/linux/ubuntu bionic InRelease Get:6 https://nvidia.github.io/nvidia-docker/ubuntu18.04/amd64 InRelease [1,096 B] Hit:7 http://jp.archive.ubuntu.com/ubuntu bionic-backports InRelease Hit:9 http://security.ubuntu.com/ubuntu bionic-security InRelease Get:8 https://packages.cloud.google.com/apt kubernetes-xenial InRelease [8,993 B] Err:8 https://packages.cloud.google.com/apt kubernetes-xenial InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 6A030B21BA07F4FB Hit:10 https://cf-cli-debian-repo.s3.amazonaws.com stable InRelease Reading package lists… Done W: GPG error: https://packages.cloud.google.com/apt kubernetes-xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 6A030B21BA07F4FB E: The repository 'http://apt.kubernetes.io kubernetes-xenial InRelease' is not signed. 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.
Solved by adding the missing key as follows
jonas@octo:~$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6A030B21BA07F4FB Executing: /tmp/apt-key-gpghome.JKpxFjtwsU/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys 6A030B21BA07F4FB gpg: key 6A030B21BA07F4FB: public key "Google Cloud Packages Automatic Signing Key <a href="mailto:gc-team@google.com">gc-team@google.com</a>" imported gpg: Total number processed: 1 gpg: imported: 1 jonas@octo:~$