I don't have a reproducible test case, but this issue was seen in production with two different user/database combination two distinct times. We can not run with slave_ok in production because of it. Each time the issue persisted until slave_ok was removed as an option to query.

We are using the luamongo (https://github.com/moai/luamongo) driver which is a thin wrapper around the c++ driver. We never saw the issue when on mongodb 1.8, we first ran into the issue after updating to 2.0.2. Originally we thought it was because we were still using a lua driver compiled against the 1.8.X C++ driver but the issue continued after upgrading to the 2.0.2 version of the driver.

When a query is sent to a secondary this is the return:

[

{"code":10057,"$err":"unauthorized db:<db name> lock type:-1 client:50.18.245.77"}

]

Any lua query, even basic one's like the following will generate the error:

local cursor = mongodb:query('mydb.datastore', '

{key:"value"}

', nil, nil, nil, 4)