apt-get updateしたらエラーが出る。

kubernatesのリポジトリのキーが何とか？

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. 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 B53DC80D13EDEF05

W: Failed to fetch http://apt.kubernetes.io/dists/kubernetes-xenial/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B53DC80D13EDEF05

W: Some index files failed to download. They have been ignored, or old ones used instead.

下記で直った

$sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys B53DC80D13EDEF05

Executing: /tmp/apt-key-gpghome.OskKevGCGE/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys B53DC80D13EDEF05

gpg: key B53DC80D13EDEF05: 1 duplicate signature removed

gpg: key B53DC80D13EDEF05: public key "Rapture Automatic Signing Key (cloud-rapture-signing-key-2022-03-07-08_01_01.pub)" imported

gpg: Total number processed: 1

gpg:               imported: 1