SysOps Interview Questions and Answer – Part 1

  • What is your favorite editor?
  • What is RAID? What is RAID0, RAID1, RAID5, RAID10?
  • Describe the general file system hierarchy of a Linux system.
  • Describe what each of the following command line utilities do:
    • tee
    • awk
    • tr
    • cut
    • curl
    • tail
    • sed
  • Command line demo:
    • Search for “my konfu is the best” in all *.py files
    • Replace the occurrence of “my konfu is the best” with “I’m a linux jedi master” in all *.txt files
    • Find all files which have been accessed within the last 30 days
  • What is the difference between virtual memory and swap ?
  • What is the difference between hardlinks and symlinks?
  • What is an inode and what fields are stored in an inode?
  • What are zombie processes ?
  • Can you have several HTTPS virtual hosts sharing the same IP?
  • What is the difference between processes and threads?
  • What is the difference between exec and fork?
  • How nginx can handle a lot of connections? What does it use inside?
    • Example of answer: Eventloop.
  • What is “nohup” used for?
  • What is an atomic operation?
  • I’ve added my public ssh key into authorized_keys but I’m still getting a password prompt, what can be wrong?
  • How do you catch a SIGHUP ? What about SIGSEGV ? What about SIGKILL ?
  • What is the Linux Kernel OOM and how does it work ?
  • What’s a chroot jail?
  • Describe the Linux boot process with as much detail as possible, starting from when the system is powered on and ending when you get a prompt.
  • What’s LD_PRELOAD and when is it used?
  • You ran a binary and nothing happened. How would you debug this?
  • When can a socket receive E_AGAIN ?
  • What is a dynamically/statically linked file?
  • A careless sysadmin executes the following command: chmod 444 /bin/chmod – what do you do to fix this?
  • I’ve lost my root password, what can I do?
  • You have accidentally deleted a running script, how could you restore it ?
  • What load balancers have you used ?
  • AWS:
    • What is the difference between an AMI and an instance ?
    • What’s EBS ? What’s an EBS snapshot ? What is the real cost of having an EBS snapshot ?
    • What’s a VPC ?
    • What’s the difference between a region and an availability zone ?
    • What’s an ELB ?
    • What’s S3 ? What are the features supported on S3 ?
Rajesh Kumar
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