W: GPG error: https://prod-cdn.packages.k8s.io/repositories/isv:/kubernetes:/core:/stable:/v1.28/deb InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 234654DA9A296436E: The repository 'https://pk

원인: 키값이 잘못됨

# 실행시 에러 발생
sudo apt-get update

조치

# K8s GPG key 생성
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key | sudo tee /etc/apt/keyrings/kubernetes-apt-keyring.asc

# repository 업데이트
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.asc] https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list

# 확인
sudo apt-get update