How should I use sudo from an upstart script?

Question

I am using upstart to run my node.js app on an Amazon Linux AMI EC2 instance. I have had a few issues getting it to work, summarized below.

In my script I had a line like this:

exec sudo -u www /usr/local/bin/node /var/www/foo/app.js >> /var/log/foo.sys.log 2>&1

When run, the job never got passed stop/waiting, and when I turned on log-priority debug I saw this line:

sudo: sorry, you must have a tty to run sudo

I ended up at this post talking about visudo and why I shouldn't use it and how it recommends using --session-command instead. So I changed the line to:

exec su --session-command="/usr/local/bin/node /var/www/foo/app.js >> /var/log/foo.sys.log 2>&1" www

The log now says (sys) Starting but initctl status foo still says foo stop/waiting.

It this point I am not sure how what to do to get this working, any help would be appreciated.

Update: I have been over this post from SO and the results are the same.

Solution

Q: "How should I use sudo from an upstart (or any other kind of system startup/init) script?"
A: "You shouldn't".

Sudo is really designed to be used interactively (hence the you must have a tty to run sudo message) -- It's not the right tool to be used in non-interactive startup scripts.

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To do what you want requires a little hackery because Upstart doesn't support launching jobs as unprivileged users (yet -- hopefully one day they'll fix this problem). The question was asked and answered over on SuperUser, but I'll reproduce it here as it's equally valuable for sysadmins:

Asking on the #upstart channel on freenode, the official take on the matter is:

A future release of Upstart will have native support for that, but for now, you can use something like:

exec su -s /bin/sh -c 'exec "$0" "$@"' username -- /path/to/command [parameters]

Comments

[voretaq7]

(There are also a number of other options mentioned on that SuperUser answer which might be worth investigating. If you find this answer useful please go visit the original question/answer on SuperUser & upvote those as well)