Running the following script under cron and it will notify you your Linode needs rebooting to pick up the latest kernel:

#!/bin/bash

curl -s "https://api.linode.com/?api_key=TODOyourlongLinodeAPIKeyhere&api_action=avail.kernels&isXen=1" | jq '.DATA' | grep "Latest.*$(uname -r)" > /dev/null
if [ $? -eq 1 ]; then
  touch /var/run/reboot-required
  echo "New Linode Kernel is available - Reboot Required" | mail -s "New Linode Kernel is available" TODO@email
fi

Rather than putting an API key on the Linode, you could also use the RSS feed:

https://www.linode.com/rss/kernels.xml

Either way works, all depends what kind of parsing you want to do.

- Les

And here's a bash script that uses the rss feed

#!/bin/bash
    curl -s https://www.linode.com/rss/kernels.xml | grep "Latest.*$(uname -r)" > /dev/null
    if [ $? -eq 1 ]
    then
        echo -n 'Not using latest Linode kernel'
    fi

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Shows 4.0.2 as the latest for me <title>Latest 64 bit (4.0.2-x86_64-linode56)</title> note the newest kernel isn't always the one marked as latest. A kernel is only given the Latest flag when Linode think it's stable.

_________________
Paid support
How to ask for help
1. Give details of your problem
2. Post any errors
3. Post relevant logs.
4. Don't hide details i.e. your domain, it just makes things harder
5. Be polite or you'll be eaten by a grue