From 5d4942a63397b46d362bec67c45e993ebbe1ddd7 Mon Sep 17 00:00:00 2001 From: abregman Date: Fri, 10 Jan 2020 02:11:02 +0200 Subject: [PATCH] 800 questions milestone --- README.md | 119 ++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 102 insertions(+), 17 deletions(-) diff --git a/README.md b/README.md index 2ca28f8..ac22ce4 100644 --- a/README.md +++ b/README.md @@ -2,9 +2,7 @@ :information_source:  This repository contains questions on various DevOps and SRE related topics -:bar_chart:  There are currently **786** questions - -:books:  To learn more about DevOps check the resources in [DevOpsBit.com](https://devopsbit.com) +:bar_chart:  There are currently **800** questions :warning:  The purpose of this repo is to help you test your knowledge and prepare for interviews. It doesn't represents a DevOps interview. Please read [Q&A](common-qa.md) for more details @@ -888,6 +886,10 @@ CSMA/CD algorithm: * hub
+
+How does a router works?
+
+
What is NAT?
@@ -1169,8 +1171,6 @@ systemd has many features such as user processes control/tracking, snapshot supp If we visualize the unix/linux system in layers, systemd would fall directly after the linux kernel. Hardware -> Kernel -> Daemons, System Libraries, Server Display. - - @@ -1188,7 +1188,7 @@ Hardware -> Kernel -> Daemons, System Libraries, Server Display. How do you kill a process in D state?
-##### Debugging +##### Debugging (Beginner)
What are you using for troubleshooting and debugging network issues?
@@ -1223,11 +1223,16 @@ Hardware -> Kernel -> Daemons, System Libraries, Server Display.
-You get a call saying "my system is slow" - how would you deal with it?
+You get a call from someone claiming "my system is SLOW". What do yo do?
-1. Check with top if anything consumes your CPU or RAM. -2. Run dstat -t to check if it's related to disk or network. -3. Check I/O stats with iostat +* Check with `top` for anything unusual +* Run `dstat -t` to check if it's related to disk or network. +* Check if it's network related with `sar` +* Check I/O stats with `iostat` +
+ +
+Explain iostat output
@@ -1238,10 +1243,20 @@ Hardware -> Kernel -> Daemons, System Libraries, Server Display. What kind of information one can find in /proc?
+
+What is the difference between CPU load and utilization?
+
+
How you measure time execution of a program?
+#### Kernel + +
+How do you find out which Kernel version your system is using?
+
+
What is a Linux kernel module and how do you load a new module?
@@ -1309,7 +1324,7 @@ Each number has different meaning, based on how the application was developed. I consider this as a good blog post to read more about it: https://shapeshed.com/unix-exit-codes -##### Storage & Filesystem +##### Storage & Filesystem (Beginner)
What's an inode?
@@ -1621,6 +1636,17 @@ This is a great article on the topic: https://www.computerhope.com/jargon/f/file What is a network namespace? What is it used for?
+
+How to check if a certain port is being used?
+ +One of the following would work: + +``` +netstat -tnlp | grep +lsof -i -n -P | grep +``` +
+
How can you turn your Linux server into a router?
@@ -1629,6 +1655,12 @@ This is a great article on the topic: https://www.computerhope.com/jargon/f/file What is a virtual IP? In what situation would you use it?
+
+Can you have more than one default gateway in a given system?
+ +Technically, yes. +
+
Which port is used in each of the following protocols?: @@ -1808,7 +1840,11 @@ If wait is not used by a parent process then a child process might become a zomb
-What happens when you execute ls?. Provide a detailed answer
+What happens when you execute ls?
+
+ +
+What happens when you execute ls -l *.log?
#### Linux Filesystem & Files @@ -1862,7 +1898,7 @@ These system calls are reading the file /my/file and 5 is the file
-What traceroute command does? How it works?
+What the traceroute command does? How does it works?
Another common way to task this questions is "what part of the tcp header does traceroute modify?"
@@ -2031,11 +2067,17 @@ Role – Ansible roles allows you to group resources based on certain functional
-Which Ansible best practices are you familiar with?. Name at least three
+How Ansible is different from other Automation tools?
+ +Ansible is: + +* Agent-less +* Minimal run requirements (Python & SSH) and simple to use +* Default mode is "push" (it supports also pull)
-What is an inventory file and how you define one?
+What is an inventory file and how do you define one?
An inventory file defines hosts and/or groups of hosts on which Ansible tasks executed upon. @@ -2092,6 +2134,10 @@ spun up and shut down, without you tracking every change in these sources. When given a written code, always inspect it thoroughly. If your answer is “this will fail” then you are right. We are using a fact (ansible_hostname), which is a gathered piece of information from the host we are running on. But in this case, we disabled facts gathering (gather_facts: no) so the variable would be undefined which will result in failure.
+
+Which Ansible best practices are you familiar with?. Name at least three
+
+
Write a playbook to install ‘zlib’ and ‘vim’ on all hosts if the file ‘/tmp/mario’ exists on the system.
@@ -2185,7 +2231,6 @@ A full list can be found at the link above. Also, note there is a significant di What is ansible-pull? How it’s different compared to ansible-playbook?
- #### :star: Advanced @@ -2638,6 +2683,14 @@ Statements are instructions executed by the interpreter like variable assignment What is Object Oriented Programming? Why is it important?
+
+Are you familiar with SOLID design principals?
+ +SOLID design principals are about: + +* Make it easier to extend functionality +
+
What are the four pillars of object oriented programming?
@@ -3383,6 +3436,10 @@ Detailed answer can be found here: http://codingshell.com/python-all-string-perm Count the number of spaces in a string
+
+Given a string, find the N most repeated words
+
+
Given the string (which represents a matrix) "1 2 3\n4 5 6\n7 8 9" create rows and colums variables (should contain integers, not strings)
@@ -3602,12 +3659,20 @@ What would be the result of is_int(2) and is_int(False)? Implement Hash table in Python
-##### Tests +##### Python Testing
What is your experience with writing tests in Python?
+
+How would you check if two strings are equal? What about booleans?
+
+ +
+How to test if an exception was raised?
+
+
What assert does in Python?
@@ -5529,6 +5594,20 @@ TODO: explain what is actually a Cookie What is faster than RAM?
+
+What is your favorite protocol?
+ +SSH +HTTP +DHCP +DNS +... +
+ +
+What is Cache API?
+
+
What is the C10K problem? Is it relevant today?
@@ -5640,6 +5719,12 @@ You can use and elaborate on one or all of the following: * Creativity (be able to support it with some actual examples)
+#### Team Lead + +
+How would you improve productivity in your team?
+
+ ## Questions you CAN ask