I have the following two lines added to my shell rc:
keychain id_rsa -q
. ~/.keychain/`uname -n`-sh
Until upgrading gnupg from 2.0.x to 2.1.x, this had worked fine, but now for every shell apart from the one in which I entered my SSH-key passphrase, I get the following error message:
* Error: Failed to start gpg-agent
Apart from this, keychain still works as intended (or so it seems at least).
A guy in the #funtoo channel told me that this could be connected to "gnupg 2.1 deprecated the environmental variable related to the agent's socket iirc".