{"id":20474,"date":"2021-03-02T21:21:45","date_gmt":"2021-03-02T21:21:45","guid":{"rendered":"http:\/\/www.devopsschool.com\/blog\/?p=20474"},"modified":"2021-03-02T21:21:45","modified_gmt":"2021-03-02T21:21:45","slug":"devops-interview-questions-and-answer-part-5-2","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/devops-interview-questions-and-answer-part-5-2\/","title":{"rendered":"DevOps Interview Questions and Answer \u2013 Part 5"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">DevOps Interview Questions: Programming<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>What is your favorite scripting\/programming language(s)? Why ?<\/li><li>General CS, algorithms Q&amp;A: 5 minutes<ul><li>Data structures &#8211; discuss possible implementations and applications:<ul><li>Binary tree<\/li><li>Hash map<\/li><li>Heap<\/li><\/ul><\/li><li>Complexity classes &#8211; discuss and give examples:<ul><li>Linear<\/li><li>Polynomial<\/li><li>NP Complete \/ NP Hard<\/li><\/ul><\/li><li>Sorting algorithms &#8211; discuss:<ul><li>What is the fastest sorting algorithm?<\/li><li>What is the complexity of quick sort?<\/li><\/ul><\/li><li>Distributed systems:<ul><li>What\u2019s Paxos?<\/li><li>What&#8217;s Raft?<\/li><li>What\u2019s consistent hashing?<\/li><\/ul><\/li><li>Hands-on coding:<ul><li>Inverse a string in place<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">DevOps Interview Questions: DevOps<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>What DevOps is? Why do we need it?<ul><li>Example of answers:<ul><li>Why do we need it?<ul><li>Increase deployment frequency<\/li><li>Lower failure rate of new releases<\/li><li>Shortened lead time between fixes<\/li><li>Faster mean time to recovery in the event of new release crashing<\/li><\/ul><\/li><li>What DevOps is?<ul><li>CALMS<\/li><li>C \u2013 Culture (promotes collaborative and open culture between Dev and Ops)<\/li><li>A \u2013 Automation (automate wherever applicable)<\/li><li>L- Learning (continuous learning &amp; experimentation)<\/li><li>M \u2013 Measure (Measure with shared metrics across the Dev and ops for better management)<\/li><li>S \u2013 Sharing (Shared delivery process across Dev and Ops to build , deploy, maintain and monitor product with mentality of One Team \u2013 One Goal)<\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><li>What is the purpose of a post-mortem meeting?<\/li><li>What is meant by Continuous Integration?<\/li><li>What are the success factors for Continuous Integration?<ul><li>Examples of answers:<ul><li>Maintain a code repository<\/li><li>Automate the build<\/li><li>Make the build self-testing<\/li><li>Everyone commits to the baseline every day<\/li><li>Every commit (to baseline) should be built<\/li><li>Keep the build fast<\/li><li>Test in a clone of the production environment<\/li><li>Make it easy to get the latest deliverables<\/li><li>Everyone can see the results of the latest build<\/li><li>Automate deployment<\/li><\/ul><\/li><\/ul><\/li><li>How would you implement CI (continuous delivery) &#8211; end to end, including source control, branches, tools, etc. ?<\/li><li>What is Continious Delivery? Continious Deployment?<\/li><li>What is the difference between Continuous Integration, Continious Delivery and Continious Deployment?<\/li><li>What\u2019s the difference between git and github ? What about git and SVN ?<\/li><li>What is&nbsp;<code>git rebase<\/code>?<\/li><li>In Git how do you revert a commit that has already been pushed and made public?<\/li><li>What is puppet\/chef\/ansible used for? What are the advantages over shell scripts ?<\/li><li>What do you understand by \u201cInfrastructure as code\u201d? How does it fit into the DevOps methodology? What purpose does it achieve?<\/li><li>How do you give your developers access to the production logs ?<\/li><li>Tell me about the worst-run\/best-run outage you\u2019ve been a part of. What made it bad\/well-run?<\/li><li>How do you monitor your application ? How do you make sure it is working ? How do you get alerts when it stops working ?<\/li><li>What would be the availability and performance metrics for a key value store ? What about for MySQL replication ?<\/li><li>How would you deploy software to 5000 systems?<\/li><li>What is caching ? Where should a large scale application cache, and what data should be cached ?<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">DevOps Interview Questions: SysOps<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>What is your favorite editor?<\/li><li>What is RAID? What is RAID0, RAID1, RAID5, RAID10?<\/li><li>Describe the general file system hierarchy of a Linux system.<\/li><li>Describe what each of the following command line utilities do:<ul><li>tee<\/li><li>awk<\/li><li>tr<\/li><li>cut<\/li><li>curl<\/li><li>tail<\/li><li>sed<\/li><\/ul><\/li><li>Command line demo:<ul><li>Search for &#8220;my konfu is the best&#8221; in all *.py files<\/li><li>Replace the occurrence of &#8220;my konfu is the best&#8221; with &#8220;I&#8217;m a linux jedi master&#8221; in all *.txt files<\/li><li>Find all files which have been accessed within the last 30 days<\/li><\/ul><\/li><li>What is the difference between virtual memory and swap ?<\/li><li>What is the difference between hardlinks and symlinks?<\/li><li>What is an inode and what fields are stored in an inode?<\/li><li>What are zombie processes ?<\/li><li>Can you have several HTTPS virtual hosts sharing the same IP?<\/li><li>What is the difference between processes and threads?<\/li><li>What is the difference between exec and fork?<\/li><li>How nginx can handle a lot of connections? What does it use inside?<ul><li>Example of answer: Eventloop.<\/li><\/ul><\/li><li>What is &#8220;nohup&#8221; used for?<\/li><li>What is an atomic operation?<\/li><li>I&#8217;ve added my public ssh key into authorized_keys but I&#8217;m still getting a password prompt, what can be wrong?<\/li><li>How do you catch a SIGHUP ? What about SIGSEGV ? What about SIGKILL ?<\/li><li>What is the Linux Kernel OOM and how does it work ?<\/li><li>What&#8217;s a chroot jail?<\/li><li>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.<\/li><li>What&#8217;s LD_PRELOAD and when is it used?<\/li><li>You ran a binary and nothing happened. How would you debug this?<\/li><li>When can a socket receive E_AGAIN ?<\/li><li>What is a dynamically\/statically linked file?<\/li><li>A careless sysadmin executes the following command: chmod 444 \/bin\/chmod &#8211; what do you do to fix this?<\/li><li>I&#8217;ve lost my root password, what can I do?<\/li><li>You have accidentally deleted a running script, how could you restore it ?<\/li><li>What load balancers have you used ?<\/li><li>AWS:<ul><li>What is the difference between an AMI and an instance ?<\/li><li>What\u2019s EBS ? What\u2019s an EBS snapshot ? What is the real cost of having an EBS snapshot ?<\/li><li>What\u2019s a VPC ?<\/li><li>What\u2019s the difference between a region and an availability zone ?<\/li><li>What\u2019s an ELB ?<\/li><li>What\u2019s S3 ? What are the features supported on S3 ?<\/li><\/ul><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">DevOps Interview Questions: DBA<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>What\u2019s ACID ? How is it implemented ?<\/li><li>What is row level locking ? Table level locking ?<\/li><li>How do you check which jobs are running?<\/li><li>Imagine you have a filesystem that supports snapshots &#8211; how do you take hot backups using volume managers (LVM\/EBS)?<\/li><li>What is the need for master\/slave replication in MySQL ? What about master\/master replication ? How does replication work in MySQL ?<\/li><li>How would you handle DB migrations? How would you automate DB migration process?<\/li><li>What pros\/cons could you tell about MySQL\/PostgreSQL?<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">DevOps Interview Questions: Networking<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>What is IPv6 ? Why should we care?<\/li><li>How does ping work ? What about traceroute ?<\/li><li>I type&nbsp;<a href=\"http:\/\/www.yahoo.com\/\">http:\/\/www.yahoo.com<\/a>&nbsp;in my browser\u2019s URL bar and I press enter. What happens ? (discuss at every OSI layer &#8211; Physical, data link, network, transport, session, presentation, application)<ul><li>DNS &amp; anycast, IP, UDP, routing, BGP, TCP, HTTP, transparent proxy<\/li><li>What is BGP?<\/li><li>What\u2019s a PTR in DNS? Why should we care?<\/li><\/ul><\/li><li>What if I change from&nbsp;<a href=\"http:\/\/www.yahoo.com\/\">http:\/\/www.yahoo.com<\/a>&nbsp;to&nbsp;<a href=\"https:\/\/www.yahoo.com\/\">https:\/\/www.yahoo.com<\/a>&nbsp;?<ul><li>Public\/private certificates, CAs, proxying, MiTM, etc.<\/li><\/ul><\/li><li>What happens when I press the send button in my email client ?<\/li><li>How do we prevent bots crawling ? How would you deal with a syn flood ?<\/li><li>How many hosts in a \/24 network? What about a \/22 ?<\/li><li>What is the difference between DNAT and SNAT ? When do you use either ?<\/li><li>What is a virtual IP address? What is a cluster?<\/li><li>What is IPv6 ? Why should we care?<\/li><\/ul>\n\n\n\n<p><strong>Reference<\/strong><\/p>\n\n\n\n<p><a href=\"https:\/\/github.com\/devops-school\/devops-interview-questions\">https:\/\/github.com\/devops-school\/devops-interview-questions<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>DevOps Interview Questions: Programming What is your favorite scripting\/programming language(s)? Why ? General CS, algorithms Q&amp;A: 5 minutes Data structures &#8211; discuss possible implementations and applications: Binary&#8230; <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[2],"tags":[],"class_list":["post-20474","post","type-post","status-publish","format-standard","hentry","category-uncategorised"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/20474","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=20474"}],"version-history":[{"count":1,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/20474\/revisions"}],"predecessor-version":[{"id":20475,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/20474\/revisions\/20475"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=20474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=20474"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=20474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}