A strange "fatal: Could not read from remote repository." with crontab

Question

I use git init --bare example.git create git repo in my localhost, user is git.

and I use root to git clone, run every minute with crontab, the command is:

*/1 * * * * git --git-dir=/opt/xxx/.git --work-tree=/opt/xxx pull 1>>/tmp/git.log 2>&1

the output log is:

Permission denied (publickey,keyboard-interactive).

fatal: Could not read from remote repository.

Please make sure you have the correct access rights and the repository exists.

Then I try:

 */1 * * * * cd /opt/xxx/ && git pull 1>>/tmp/git2.log 2>&1

But the output is the same.

If I run in command line, all is ok:

Already up-to-date.

I don't know why can't run with crontab?

Answer 1

Agent-based authentication requires that the SSH process has access to the $SSH_AUTH_SOCK environment variable, but that variable won't be set when run via the crontab. You may want to consider switching to a passphrase-less keypair or an anonymous authentication method.

If that's not an option you could write the contents of the $SSH_AUTH_SOCK environment variable (possibly also $SSH_AGENT_PID) to a local file that you can read from your crontab-run script and set the variables so that they're available to SSH.

One last option is to drop the crontab entry and manually start up a shell script that runs as a daemon and periodically performs the pull.