Nov 2013

Sun, 17 Nov 2013

ssh: Group readable id_rsa identity file

Let's say you want to use a system wide ssh identity file to access (or push) shared server state from different users on the system.

The naive way is to chmod 0640 /system/wide/id_rsa. Only ssh will complain loudly about that without a way to disable the error:

Permissions 0640 for '/etc/git-readonly/id_rsa' are too open.
It is recommended that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /etc/git-readonly/id_rsa

The usual answer to this is that you do not do that. Use different keys per user or host based checking or an ssh-agent.

But lets say you really want to. A viable workaround is to make a copy of the file with the right permissions:

My ssh wrapper for this is:

cat /etc/git-readonly/id_rsa > "$RSA"
chmod 0600 "$RSA"
exec ssh  -o UserKnownHostsFile=/etc/git-readonly/known_hosts -o StrictHostKeyChecking=yes -i "$RSA" "$@"

Use at your own risk!

posted at 16:00 | path: /unix | permanent link to this entry

Sat, 16 Nov 2013

Python: gevent's WSGIServer, wsgi vs. pywsgi

The gevent wsgi server is one of the fastest out in the open. I switched part of my applications to it and everything worked fine after restarting the server and testing locally. Unfortunately my haproxy frontend loadbalancer is not able to see the new backend though. Turns out that gevent.wsgi does not support HTTP 1.0 which haproxy uses for health checking.

The simple solution is to use gevent.pywsgi. This has some performance penalty though.

An alternative might be (untested) to configure haproxy with HTTP 1.1 healthchecks:

option httpchk OPTIONS / 1.1

posted at 16:00 | path: /python | permanent link to this entry

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