Ubuntu – La mise à jour échoue avec « gnutls_handshake () a échoué: erreur dans la fonction pull. »

Je suis nouveau sur Ubuntu et Kubernetes. Lorsque j’essaie de configurer un cluster Kubernetes, le update échoue avec le message suivant:

 $ sudo apt-get update
Err:9 ht#tps://packages.cloud.google.com/apt kubernetes-xenial/main amd64 Packages
gnutls_handshake() failed: Error in the pull function.
Reading package lists... Done
W: The repository 'http://apt.kubernetes.io kubernetes-xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch https://packages.cloud.google.com/apt/dists/kubernetes-xenial/main/binary-amd64/Packages gnutls_handshake() failed: Error in the pull function.
E: Failed to fetch https://packages.cloud.google.com/apt/dists/kubernetes-xenial/main/i18n/Translation-en gnutls_handshake() failed: Error in the pull function.
E: Some index files failed to download. They have been ignored, or old ones used instead.