执行sudo apt update时出现cloud-sdk未签名GPG错误，求解决方案

Got it, this is a super common hiccup when your system doesn’t have the right public key to verify the Google Cloud SDK repository. Let’s walk through the fix step by step:

• First, download the official Google Cloud public key and add it to your system’s dedicated keyring (this is the modern, secure way instead of using the old apt-key default ring):

  curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key --keyring /usr/share/keyrings/cloud.google.gpg add -
  

  If curl isn’t installed on your system, use wget instead:

  wget -q -O - https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key --keyring /usr/share/keyrings/cloud.google.gpg add -
  

• Next, update your Cloud SDK repository configuration to tell apt to use this new keyring for verification. Open the repository file with your favorite text editor (I’ll use nano here):

  sudo nano /etc/apt/sources.list.d/google-cloud-sdk.list
  

  Find the line that looks like this:

  deb http://packages.cloud.google.com/apt cloud-sdk main
  

  Replace it with this line (the signed-by flag points to the key we just added):

  deb [signed-by=/usr/share/keyrings/cloud.google.gpg] http://packages.cloud.google.com/apt cloud-sdk main
  

  Save and exit the editor (for nano, press Ctrl+O, then Enter, then Ctrl+X).

• Finally, run apt update again to confirm the error is gone:

  sudo apt update
  

That should resolve the "NO_PUBKEY B53DC80D13EDEF05" and "repository is not signed" errors. The key here is making sure apt knows exactly which key to use for verifying the Cloud SDK repo, which we set up with the signed-by parameter.

内容的提问来源于stack exchange，提问作者dwightjl