W: GPG error: http://ubuntu-cloud.archive.canonical.com precise-updates/grizzly Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 5EDB1B62EC4926EA

how to fix this issue :

#apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 5EDB1B62EC4926EA
#apt-get update
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