Google Interview – Data Center IT Technician

* Updated 2011-01-29
* Updated 2011-03-08 Dtek contributed some more questions from the first interview.
* Updated 2011-03-23 – Added question about PCI/PCIe and DOS partitions. Also I have been asking the few who have commented to add their input but not so much feedback yet. Feel free to drop me an e-mail or put in a comment :)
* Updated 2011-03-24 – Wrote a little more about the ‘100 broken computers’ question.
* Updated 2011-05-21 – Added some more detail/discussion about the questions in the first section.

A little while ago I had an interview for a position with Google as a Data Center IT Technician, I never signed an NDA so should be safe to put them up here :)

However, if you want to play it safe I’d refrain from posting here until after the interviews are over.

I didn’t get the job, they never answered why I didn’t pass when I replied back for some feedback (besides the template e-mail).

If you read this go ahead and comment, maybe we can figure out a better way to approach the questions :)

First Interview

First there was one interview which had 20 questions (I don’t remember all) around basic (older – like no SATA) PC stuff:
What are all the components in a PC or Server?
PC: chassi, system board, psu, cpu, ram, hdd, fans, cables, graphics card, dvd, monitor, keyboard/mouse
Server: same with deduction of a extra graphics card (is one on the system board), and addition of hdd controller, possibly backplane, no cd/dvd, extra nic, double cpu, ram, psu, fans, remote monitoring/console.

What protocol is used by ping? ICMP (this is a sneaky question – an obvious fault is to go for TCP or UDP)
How many IDE devices can you have in a PC?
– two per channel (usually 4)
How many can you have on each channel? What are they called? – 2 / master and slave
What is the resolution in Windows 2000 safe mode? – 800×600 or 640×480?- see this link on mydigitallife or this post on tom’s hardware.
What is a MAC address?Media Access Control – a unique identifier for network devices. Used by many protocols.
What is the name of the Ethernet plug?RJ45
How do you recognize a broken hard drive without software or removing it from the machine? – 1) Noise (tick tack sound of the arm getting stuck/hitting something) 2) Any leds on the disk, system board, controller 3) Any vibration or anything from the disk?
How do you find the first disk in a linux OS? – Look under /dev/ for a disk like /dev/sda(SATA) /dev/hda (PATA). Then /dev/sda1 is the first partition.
Name two devices needed to make a network: switch and router (well, network card (NIC) and router should do it, or a switch and network card.. depends how big you want to make it, really i guess you can have a network with a crossover cable and two nics).
What is BIOS? Basic input/output system. Responsible for initializing hardware, POST/startup diagnostics, boot the OS and varies hardware settings.
What is the bit rate of a serial interface of a network device? – the default apparently in hyperterminal – 9600 (this might be tricky, in my experience this varies between the devices – max is probably 115200bps). Maybe what they are asking for is what is the default speed of a Cisco switch’s aux or console port? If so, the answer is 9600.
What is the port used for HTTP? – 80
What is the difference between PCIe and PCI? – PCI-e is newer than PCI and PCI-x. The slots look different and they are not compatible.
How many primary partitions can you have in DOS?
– Four primary and maximum one active per disk. See this link for some explanations. Unsure at this stage what the exact question was.
What did you do in your previous jobs?
Would you be able to re-locate?

What does HTTP stand for? Hypertext Transfer Protocol
What controls GPU CPU Mem at boot up?
What is ROM?
Read Only Memory – Used for storing data that you do not want somebody to write to.

Length of cat5 transmission? 100m
What does NIC stand for? 
Network Interface Card

What is the standard type of filesystems now? disk filesystem and network filesystems
How would you create an EXT4 filesystem on the first partition of the first SCSI drive? 
mkfs.ext4 /dev/sda1
How would you install lilo? 
How do you get IP info from Linux or Windows? “ip addr” or “ifconfig” in Linux and “ipconfig” in Windows.
What is the subnet mask for a Class B Network?
255.255.0.0

Second Interview

Then there was a second one that was done by a person who worked in a data center and had questions like these:

You have 100 broken computers, how do you proceed.
Personally I didn’t do very well on this question I think.
There are lots of ways to approach this one, how far can you take it?
One way to make this a little easier/visible would be to make a tree or mindmap and keep on expanding it.

But thinking about this afterwards I would probably approach it something like this, (not necessarily in this order):

  1. Get an overview – where are they, what kind of hardware, importance, severity of problem, the wider you can make this the better. To have this done automagically is important and speeds up troubleshooting immensely. Consider monitoring softwares like nagios, ganglia, cactii. They not only monitor hardware but can also services.
  2. What’s the status of the central components? Network, power, etc.
  3. Hopefully not all have the same problem, try to find certain groups of them that have the same obvious error.
  4. Maybe there are more than one underlying issues, but they appear to be the same – or gives the same problem.
  5. Maybe there is one problem on one computer that is causing problem for all the rest. For example bad ethernet/fibre channel card or cable can cause network interruptions on the whole network or SAN.
  6. Maybe a service and there is something in that software on one node that is causing this issue. Like a job that runs on many machines but it broke on one machine and that caused the rest to break.
  7. Look in logs of the systems/services.
  8. Run a diagnostic CD on computers like ultimateboot CD to look for hardware errors. Server vendors may have their own diagnostic tools. memtest86 is a good boot CD for memory testing (probably best to test memory that way, the least amount of memory locked by the OS)
  9. For severe hardware problems you can look in the POST of the machine, check leds on them, but for 100 machines this might be more of a last resort.
  10. If you suspect the problem is SW – again try to find something they have in common – same manufacturer, same softwares/patches installed. Maybe this software has a monitoring part that can tell you more. Check the logs.
  11. When did the problem start? At the same time as a power outage, after a patch deployment, etc.
  12. Are they all physically close? Anything else gone down?

How do you see what happens during boot of the OS in Linux?
Answer: output of command dmesg and also in /var/log/syslog
Where do you find the logs in Linux?

Answer: /var/log
How do you mount a disk?

Answer: mount
Every boot?

Answer: fstab
How do you see what version of the kernel is running?
Answer:  uname -v (-r gives 2.6.x etc)
How do you put an image on a pc?
Answer: pxeboot as an example
How do you turn a room into a data center?

Maybe something like this? If you have any additions please go ahead and let me know :)

floor strong enough to hold the weight of all the equipment?
physical security – bar windows, access control(keys), cameras, guards
ventilation – perforated tiles?
cooling
anti-fire
racks
UPS – electrical work

What is the difference between a switch and a router
said that the diff is that switches are closer to the hosts and the routers are further away -> in the core
Did you have experience writing documents – kb?
Worst job you ever had?
What do you expect from your colleagues and your boss?
What do you do outside work?
Do you have any questions?

49 thoughts on “Google Interview – Data Center IT Technician

  1. Serge

    Hi Johan!
    Thank you for this excellent review of your interviews whith Google. I’m from Netherlands and recently have applide to the same position. Today I had my first phone interview, it was really easy and I alredy get scheduled for second one, next week. As far as I can see the questions of second interview is also not so hard but at least I will be more prepared and confident :) And would you please try to remember is there were another questions? Thanks!

    Reply
    1. guldmyr Post author

      Hey!

      Glad you liked it!

      I wrote this a little too late after I took the interview so I missed a few questions on the first one.

      But on the second one I wrote them down as I got them so those are all that I got!

      However I suspect that it’s a bit up to each interviewer to what questions they ask.
      If you get any more I would love to hear back from you afterwards :)

      Hope the interview goes well for you!

      Reply
          1. Serge

            Heh, they invited me to third, onsite interview. Will see what happens..
            Btw the questions on second interview was almost the same as yours.

            Reply
  2. Ben

    Thanks much for this, interviewing on phone for the Operations Tech Assistant today.

    I doubt i will have all of the same questions, but it was some good insight.

    Reply
    1. guldmyr Post author

      Yeah maybe not the ones about data center.

      I suspect they’re not so strict in terms of the questions on the secondary interview ;)

      That’s how it sounded anyway.

      Reply
  3. dtek

    just finished my 1st phone interview… I think I did well, he said he is going to forward it to the tech guys and maybe I’ll have a 2nd interview… :)

    I found this site afterwards… but I can add some q’s if you want

    Reply
    1. guldmyr Post author

      Sweet!

      Yeah please do – I can add them to the post (with your nick in there) so people don’t have to browse through the comments :)

      Reply
  4. Sully

    I’ve gotten through my phone interviews for a data center facilities technician. Haven’t heard back on when/if I have an onsite but I should this week. I can add what I was asked if you want. It was pretty specific for that job though.

    Reply
    1. guldmyr Post author

      Hey Sully!

      Ah sweet, hope you get through!

      Data Center Facilities -> is this basically about the non-it stuff isn’t it?

      Would be awesome to see what kind of questions are asked for that kind of job yeah.

      Yeah, please add the questions if you want to :)

      Reply
  5. Chris

    Hey,

    I recently applied to Google and wanted to share some information, as this blog helped me a lot. I have applied for the position Data Center Technician in Frankfurt, Germany and sent my resume four weeks ago.

    After a couple of days I got contacted by a Google Recruiter in Ireland telling me that my cv was quite good and they’d like to schedule an interview for me on the next day. The same guy called me and asked me some basic questions in the beginning – like the ones that you mentioned (network setup, tcp/udp, pc hardware).

    A week later I got scheduled with a technician to have a telephone interview, so a guy from the US called. His questions were a bit “tougher” but not challenging at all. He wanted to have step to step explanations about basic unix/linux administration.

    – Explain how to add a new harddrive in Linux (Start from the scratch with holding the hdd in your hand)
    – What does DNS stand for and whats its purpose
    – What file in a Linux file system is responsible for DNS (resolve.conf)
    – What file in a Linux file system is responsible for the IP configuration (/etc/network/interfaces)
    – What does nslookup do
    – How to get into safe boot (runlevel 3)
    – If you do “ls” in the root directory, which folders are you going to see
    – What protocol is “ping” using
    – What three commands are you using, when a machine is running slow (maybe various – told him I’d start with “uptime” “free -m” “smartctl” – he was fine with that)
    – What is the difference between bin and sbin (user binaries / system binaries)
    – What is /usr/ containing (unix system resources)
    – What is /var/ containing (variables)

    That call happened last Friday and today I got a call from the Irish recruiter telling me I was scheduled for an onsite interview on next Thursday.

    Seeing whats going to happen there.

    Reply
    1. guldmyr Post author

      Hey Chris!

      All the best of luck on that on site interview!

      Thank you very much for posting the questions here, I am glad to hear that you got some help from the article.

      I get the impression that linux knowledge is quite important :)
      Like I knew that there was a /bin or /sbin but never thought about why there are two..

      http://www.pathname.com/fhs/pub/fhs-2.3.html

      Explains them pretty well in case anybody else reads this.
      Basically system binaries are for binaries that require that you have root-access.

      Reply
  6. Chris

    I got scheduled for Thursday 28th April 10.00 CET.

    The interview is setup to last two hours – 2x 60 min interview. I got told to prepare for basic UNIX stuff.

    Reply
    1. guldmyr Post author

      Excellent Chris :)

      For us who aren’t that awesome on *nix, do you have any tips to get to know basic UNIX stuff?

      Have fun on the interview!

      Reply
    2. LatinGuy

      Hey Chris , i wanted to know if you have any hint for me about your x2 60 min ( long ) second interviews with them :)) , thx a lot !

      Reply
  7. LatinGuy

    Hello guys , i had my first interview with the google people , was quite simple , they make questions about networking like protocol of ping , user permissions , hardware related stuff , easy things , so i go for the second interview , where i am going to record and tell you all exactly what i was asked .

    But what i would love to know is what is going on on the third onsite interview ? , do they sit you like a monkey and ask you to perform some task in some server ? .

    Will write soon over here my results and questions more detailed . : )))

    Reply
    1. guldmyr Post author

      Hello and welcome :)

      I’ve sent a query to Chris through another medium so we’ll see if he gets back, I hope so!

      Reply
  8. necr0

    I just got off the phone with Google for the Data Center tech position. He asked me what components do I need to build a basic server, how to configure a network card under Linux (ifconfig), troubleshoot a computer that its video card is not working, what level of knowledge I had with Linux also with scripting or other programming languages. He asked me about IPv4, what is a net mask and what is it used for, and what is DNS. He also asked about the difference between IDE connectors and SATA.

    It went pretty goof IMHO, hopefully in a week I should be hearing back from them.

    Reply
      1. Aegil

        Hey,

        did you get any further with google, I am applying myself at the moment but seems your a bit further ahead.

        Did you have the recruiter screen and then the first engineer screen yet? And what sort of stuff did they ask for those?

        Reply
  9. S.H.

    Hey
    so keep on learning and applying ;-) but note for the first interview(s) there is a question database in place so the questions presented to evaluate the candidates suitability initially will be pretty random and the pool of questions in changing over time. The pool is big. For the follow up interviews there will be pretty decent drill down on details happening, too.
    So keep on going!

    Reply
  10. necr0

    Well.. didn’t get the job lmao, for some reason I knew that was going to happen… Oh Well, maybe next time :)
    This is good info, helped me out a lot!

    Reply
  11. John

    Thanks for the interview questions..one of the bank scheduled me for Data center operator interview.as a beginner what they will ask to me, i mean basic questions..

    Reply
  12. kaycee

    Hello all, I was interviewed today and it all went negative after missing some questions which I had never pay much attention to. Is there a way we can read more together since we have similar interest. I applied for data center engineer. let talk more !

    Reply
    1. guldmyr Post author

      Hey, well I didn’t get the google job (and likely never as I have posted this post :).

      So you want to read something more? Is there a specific topic you would be interested in? I could perhaps write something here on the blog :)

      Reply
  13. kaycee

    I was advice to re-apply again. I want to improve more on Linux, Hardware and Network. For Linux which I will prefer to pay much attention to one particuar Linux. I have basic knowledge of Redhat, Ubuntu and Fedora but at the moment I want to focus one one, is there anyone you have in mind. Is there anyone living in Finland.

    Reply
    1. guldmyr Post author

      Hi.
      I do not know if google uses something based on Rhel. Would say it has too old software compared to debian or fedora.

      There are people living in Finland. Hamina is remote. You can’t live in Helsinki and commute there.

      Reply
  14. Scool

    A few days ago a finished my 2x 45minute interviews for a position in their Datacenter in Belguium. Unfortunalty i didn’t pass it.
    Those 2 interviews occured on the same day. One interview Linux/Hardware related and one network related.

    The first interview was very kind, polite, helpfull and joyfull.
    He started with a warmup question. Simple things about my current job description. So just chatting here.

    Then some of the questions was :
    Can you please describe the boot sequence of a plain PC ? (The answer is the detailed sequence from pressing the power button until the 1st boot device)
    Where the date is stored?
    What is the Master Boot Record ?
    How the Computer knows which one is the bootable device?
    What is Permissions 644 stands for ?
    How you can change the ownership of a folder or a single file?
    What is the command to clone a hard disk?
    If you do not have an ssh connection, neither ipmi , how you can copy a file? (telnet)
    You are a team leader and you have 2 workers. Describe the procecure of racking 100 servers.
    (By my opinion, this question has to do with leadership skills and to check if you have experience with racking servers etc. I don’t think that there is a 100% correct answer here, hence it depends.
    But in general anyone who has worked in a datacenter has the necessery skills and basic knowleage of how to do that.)
    What are the benefits of two network cards?
    If you “team” two network cards will you get the sum of 1+1=2 gigabits?
    How do you recover the root password if you forgot it? / What is a live cd? / What is single user mode.
    How you can sniff a network activity of a network port on the same lan?
    What is hub?
    What is traceroute? how does it works?
    What is dns?
    How a provides knows which domain points to which ip?
    Lets suppose that your browser of your home computer opens the websites very slowlly. How will you troubleshoot this situation?

    This is as far as i can remember. I think i am missing 2-3 questions. Also i didn’t sign any disclosure aggreement.
    I am preety sure that they know what’s going one. The procudure changed on the last two years.
    I received the answer after 4 days. It seems that they speed up the hiring procedure.

    Reply
  15. Raja

    Hi,
    Difference between Switch and Router.
    The First point “Never forget the OSI layer. Switches operate @L2 and Routers @L3.

    Switches forward the frames based on MAC and Routers forward the packets based on the IP address of the destination. Routers are intelligent devices than switches.

    Switches are in the access layer and routers are placed in the Aggregation layer.

    In core layer, MLS are used rather than Routers as per my knowledge.

    PDU(protocol data unit for Switches : Frames and Routers: Packets).

    Routers will not drop packets unless the destination device is down and will check the path based on the Routing protocol used (EIGRP, OSPF, BGP).

    Cheers,
    Raja

    Reply
  16. c.babu

    today i had google datacenter round 1 interview.

    1. how to see kernal version
    2. what command to change file permissions.
    3.what command to stop process in linux.
    4.how to see if host is live.
    5. is DNS tcp or udp
    6 DNS port.
    7how to check server speed.
    8.how to avoid electro stact currrent.
    9. how to change password in linux

    Reply
    1. DC Passionate

      Applied for the data center hardware operations engineer role.

      1st interview:
      got a call from the recruiter to answer some basic Linux/hardware questions. (durations ~15 minutes call).

      2nd interview: ~ 45 min
      A Google Hangouts interview.
      Was to benchmark my Linux knowledge; come up with solutions for given scenario’s. It starts easy and gets more difficult until they reached the bottom.

      3rd interview: ~ 45 min
      Also through Google Hangouts.
      Was about networking. Also started with basics. The audio/video quality was really bad. It made the interview confusing and therefore useless. At some point the interviewer was asking about “rooting”. I only have some basic networking knowledge and I don’t know what you mean that. I gave up. After the interview I figured out he was asking about ‘routing’, but because of his british pronunciation it sounded like rooting. 😀

      I don’t expect to be hired. But It was fun to get on this track and get to know Google from a different sight.

      Reply
  17. Prudvi

    Hi I am Nayak, thanks for sharing your experiences and I got one teat from AWS data centre and they send me a link for the online exam .can you share if you have any experience.

    Reply
  18. networkguru

    i have interview with google or hardware operation engineer. kindly please help to give an idea what kind of question to be asked. is anyone had the applied for the same position guys ? thank you

    Reply
  19. omsakthi

    Thanks a lot, Guys.!

    I will be attending 2nd round interview in Gooogle for Linux/DC Engineer on 4th Jan.

    I don’t have hope even I have good knowledge, Let me see

    Reply
  20. debo

    I will be attending a first phone interview for a Data Center Hardware Operations Engineer today. Please any hint on questions

    Reply
  21. Pandi

    Hi Guys, I have passed the two hangout interviews,
    1 Interview about Linux
    2 Interview about network
    now they asked me to come for onsite interview at google @ hyderabad.Can any one who experieced the on site interivew for data center operation engineer jobs at google.
    what are all the questions & process number of rounds.

    Thanks in Advance.

    Reply
  22. Kumar

    Hi Guys, I am invited for the hangout Technical interview 2X45Min for the position Data center Hardware operation Engineer. Would you guys have any recent interviews for this position and the questions asked by Google Engineers ?

    Thanks,

    Reply

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