When updating ubuntu, i got following error.
root@cloud2:/etc/apt/trusted.gpg.d# apt-get update Ign http://security.ubuntu.com trusty-security InRelease -- -- -- -- Hit http://archive.ubuntu.com trusty-updates/universe i386 Packages Fetched 3732 B in 3s (1035 B/s) Reading package lists... Done W: GPG error: http://security.ubuntu.com trusty-security Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32 W: GPG error: http://archive.canonical.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32 W: GPG error: http://archive.ubuntu.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32 W: GPG error: http://archive.ubuntu.com trusty-updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32 root@cloud2:/etc/apt/trusted.gpg.d#
This is fixed by running
apt-key adv --recv-key --keyserver keyserver.ubuntu.com 3B4FE6ACC0B21F32
3B4FE6ACC0B21F32 is the key from the error message when you run apt-get update.
# apt-key adv --recv-key --keyserver keyserver.ubuntu.com 3B4FE6ACC0B21F32 Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.nOwyPbbL9k --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --recv-key --keyserver keyserver.ubuntu.com 3B4FE6ACC0B21F32 gpg: requesting key C0B21F32 from hkp server keyserver.ubuntu.com gpg: key C0B21F32: "Ubuntu Archive Automatic Signing Key (2012) <[email protected]>" not changed gpg: Total number processed: 1 gpg: unchanged: 1 #
