Broken signatures

What happens if you leave an Ubuntu machine running for a couple years and then try to update? Sometimes signatures expire...

Err:6 http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/1.19/xUbuntu_20.04  InRelease
  The following signatures were invalid: EXPKEYSIG 4D64390375060AA4 devel:kubic OBS Project <devel:kubic@build.opensuse.org>

To resolve: (from https://github.com/containers/podman.io/issues/296#issuecomment-1455207534)

wget -qO - https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/xUbuntu_22.04/Release.key | sudo apt-key add -

Err:3 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

To resolve: (from https://github.com/kubernetes/release/issues/1982#issuecomment-1415573798)

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | gpg --dearmor | sudo dd status=none of=/usr/share/keyrings/kubernetes-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt update