1. describe unix boot sequence, scenario bases questions for debugging, this can be in depth and will involve good unix knowledge, so be prepared on unix internals. 2. python/shell scripting, over the phone you may be asked for your approach,in actual f2f round you will asked to code in real time on a whiteboard or a pen and paper. 3. AWS related questions on various services, except for EC2 etc which are common ones. 4. Java core knowledge, thread dump and heap dump analysis and clear knowledge of analysing stack traces for debugging/troubleshooting server issues. 5. scenario based questions on how will you work through a production issue etc. 6. clear understanding of DNS, http, API calls, basic networking concepts. 7. have clear monitoring understanding on the new tools like newrelic, pagerduty, nagios, sitescope etc. 8. if you have chef/puppet then you will assessed on these as well.