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I have an upstart script that does the following

start on runlevel [2345]
stop on runlevel [06]


pre-start script
    exec >/dev/kmsg 2>&1
    mkdir -p /var/log
    mkdir -p /var/www
    echo "Fetching app from $REPO"
    girror $REPO /var/www
    if [ -f /var/www/package.json ]; then
        echo "Installing npm modules"
        cd /var/www
        npm install
end script

post-stop script
    exec >/dev/kmsg 2>&1
    echo "stopped"
end script

    exec >/dev/kmsg 2>&1
    export NODE_ENV=production
    export port=80
    echo "Starting app.js on port 80"
    cd /var/www
    node app.js
end script

I am running the script as root. The log files of the application suppose to go to /var/log/syslog but they don't go there.

However, I do see the app log when running dmesg | tail -f

Using kernel 3.5.0-46

Anyone know why it doesn't work ?

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1 Answer 1

It's happening because your script explicitly redirects all output to dmesg:

exec >/dev/kmsg 2>&1
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I have the exact script running on a different ubuntu machine on AWS and it is redirecting okay. –  Michael Mar 6 '14 at 0:12
@Michael: What kernel version is it running? –  grawity Mar 6 '14 at 0:13
the problematic one is running 3.5.0-46-generic #70~precise1-Ubuntu the one that works is running 3.2.0-31-virtual #50-Ubuntu –  Michael Mar 6 '14 at 0:16
@Michael: No. Rather, on the working machine, there is no dmesg input at all. Kernels before 3.5 did not have a writable /dev/kmsg device, so the exec line fails, the script ignores errors, and simply continues logging to where it was redirected previously (by Upstart). –  grawity Mar 6 '14 at 0:19
@Michael: Your original question does say the opposite – you wrote that it does not work because logs go to dmesg and not syslog. –  grawity Mar 6 '14 at 0:25

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