Adding GPG key inside docker container causes "no valid OpenPGP data found"

The solution provided by @xdays works around the problem, but also works around the protection that ssl is providing. You could install the ca-certificates package before issuing your wget statement and it should work with ssl.

Add the following line before your call to wget:

RUN apt-get install -y ca-certificates wget

it seems that the problem is wget, add --no-check-certificate to your wget, and everything is ok.

# wget --no-check-certificate -O- https://download.newrelic.com/548C16BF.gpg | apt-key add -                                                                 --2014-01-12 09:29:30--  https://download.newrelic.com/548C16BF.gpgResolving download.newrelic.com (download.newrelic.com)... 50.31.164.159Connecting to download.newrelic.com (download.newrelic.com)|50.31.164.159|:443... connected.WARNING: cannot verify download.newrelic.com's certificate, issued by `/C=US/O=GeoTrust, Inc./CN=GeoTrust SSL CA':  Unable to locally verify the issuer's authority.HTTP request sent, awaiting response... 200 OKLength: 1682 (1.6K) [application/octet-stream]Saving to: `STDOUT'100%[=================================================================================================================================================>] 1,682       --.-K/s   in 0s      2014-01-12 09:29:31 (15.1 MB/s) - written to stdout [1682/1682]OK

I ran into this issue when i was installing docker.

run sudo apt install apt-transport-https ca-certificates curl software-properties-common

You can refer here.

And then curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -