minor order changes

README.md

@@ -2,7 +2,7 @@
 
 :information_source:  This repository contains questions on various DevOps and SRE related topics
 
-:bar_chart:  There are currently **800** questions
+:bar_chart:  There are currently **804** 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
 
@@ -2593,13 +2593,17 @@ Swarm management which means you can create new swarms in Docker Cloud.
 #### :baby: Beginner
 
 <details>
-<summary>What is Kubernetes?</summary><br><b>
+<summary>What is Kubernetes? What use cases is it good for?</summary><br><b>
-</b></details>
 
-<details>
+Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications.
-<summary>Why Docker isn't enough? Why do we need Kubernetes?</summary><br><b>
 
-Kubernetes is especially good for scenarios when you no longer running small number of containers. When you have to scale from 3 containers for eaxmple to hundreds or thousands of containers.
+To understand what Kubernetes is good for, let's look at some examples:
+
+* You would like to run a certain application in a container on multiple different locations. Sure, if it's 2-3 servers/locations, you can do it by yourself but it can be challenging to scale. Also, running them is not only running the container but also react on different events.
+
+* Performing updates and changes across hundreds of containers
+
+* Handle cases where the current load requires to scale up (or down)
 </b></details>
 
 <details>
@@ -2607,17 +2611,44 @@ Kubernetes is especially good for scenarios when you no longer running small num
 </b></details>
 
 <details>
-<summary>What is a worker?</summary><br><b>
+<summary>What is a Kubernetes Cluster?</summary><br><b>
+
+A cluster consists of a Master (which coordinates the cluster) and Nodes where the applications are running.
+</b></details>
+
+<details>
+<summary>What the Master is responsible for?</summary><br><b>
+
+The master coordinates all the workflows in the cluster:
+
+* Scheduling applications
+* Managing desired state
+* Rolling out new updates
+</b></details>
+
+<details>
+<summary>What is a Node?</summary><br><b>
+
+A node is a virtual machine or a physical server that serves as a worker for running the applications.
+It's recommended to have at least 3 nodes in Kubernetes production environment.
+</b></details>
+
+<details>
+<summary>Explain what is Kubelet</summary><br><b>
+
+Kubelet is an agent running on each node and responsible for node communication with the master.
+</b></details>
+
+<details>
+<summary>What is Minikube?</summary><br><b>
+
+Minikube is a lightweight Kubernetes implementation. It create a local virtual machine and deploys a simple (single node) cluster.
 </b></details>
 
 <details>
 <summary>Explain what is a Kubernetes pod</summary><br><b>
 </b></details>
 
-<details>
-<summary>Explain what is a Kubernetes node</summary><br><b>
-</b></details>
-
 <details>
 <summary>True or False? A pod can manage multiple containers</summary><br><b>
 </b></details>
@@ -2626,14 +2657,6 @@ Kubernetes is especially good for scenarios when you no longer running small num
 <summary>How do you monitor your Kubernetes?</summary><br><b>
 </b></details>
 
-<details>
-<summary>What is kubectl? How do you use it?</summary><br><b>
-</b></details>
-
-<details>
-<summary>What is kubconfig? What do you use it for?</summary><br><b>
-</b></details>
-
 <details>
 <summary>You suspect one of the pods is having issues, what do you do?</summary><br><b>
 
@@ -2650,10 +2673,6 @@ Setting the replicas to 0 will shut down the process. Now start it with `kubectl
 <summary>What the Kubernetes Scheduler does?</summary><br><b>
 </b></details>
 
-<details>
-<summary>Explain what is Kubelet</summary><br><b>
-</b></details>
-
 <details>
 <summary>What happens to running pods if if you stop Kubelet on the worker nodes?</summary><br><b>
 </b></details>
@@ -2662,6 +2681,30 @@ Setting the replicas to 0 will shut down the process. Now start it with `kubectl
 <summary>Describe how roll-back works</summary><br><b>
 </b></details>
 
+#### Kubernetes Commands
+
+<details>
+<summary>What is kubectl?</summary><br><b>
+</b></details>
+
+<details>
+<summary>How do you:
+
+  * Check the cluster status?
+  * Check the status of the nodes?</summary><br><b>
+</b></details>
+
+<details>
+<summary>What the following commands do?
+
+  * kubectl get nodes
+  * kubectl </summary><br><b>
+</b></details>
+
+<details>
+<summary>What is kubconfig? What do you use it for?</summary><br><b>
+</b></details>
+
 ## Coding
 
 <a name="coding-beginner"></a>
@@ -2832,7 +2875,20 @@ There are many other characteristics but these are the main ones that every pyth
 </b></details>
 
 <details>
-<summary>What built-in types Python has? Which of them are mutable? How can you show that a certain data type is mutable?</summary><br><b>
+<summary>What built-in types Python has?</summary><br><b>
+
+    List
+    Dictionary
+    Set
+    Numbers (int, float, ...)
+    String
+    Bool
+    Tuple
+    Frozenset
+</b></details>
+
+<details>
+<summary>What is mutability? Which of the built-in types in Python are mutable? How can you show that a certain data type is mutable?</summary><br><b>
 
 The mutable data types are:
 
@@ -2851,10 +2907,6 @@ The immutable data types are:
 You can usually use the function hash() to check an object mutability. If an object is hashable, it is immutable (although this does not always work as intended as user defined objects might be mutable and hashable).
 </b></details>
 
-<details>
-<summary>Explain set and frozenset types. What would you use them for?</summary><br><b>
-</b></details>
-
 <details>
 <summary>In Python, functions are first-class objects. What does it mean?</summary><br><b>
 
@@ -2869,20 +2921,6 @@ def my_function():
 You can then assign a function to a variables like this `x = my_function` or you can return functions as return values like this `return my_function`
 </b></details>
 
-<details>
-<summary>What is PEP8? Give an example of 3 style guidelines</summary><br><b>
-
-PEP8 is a list of coding conventions and style guidelines for Python
-
-5 style guidelines:
-
-    1. Limit all lines to a maximum of 79 characters.
-    2. Surround top-level function and class definitions with two blank lines.
-    3. Use commas when making a tuple of one element
-    4. Use spaces (and not tabs) for indentation
-    5. Use 4 spaces per indentation level
-</b></details>
-
 <details>
 <summary>What is the result of running <code>[] is not []</code>? explain the result</summary><br><b>
 
@@ -3093,7 +3131,7 @@ print("{0:.3f}".format(sum(li)/len(li)))
 ```
 </b></details>
 
-#### Lists
+#### Python Lists
 
 <details>
 <summary>How do you get the maximum and minimum values from a list? How to get the last item from a list?</summary><br><b>
@@ -3260,6 +3298,22 @@ while n > 0:
 ```
 </b></details>
 
+<details>
+<summary>Sort a list of lists by the second item of each nested list</summary><br><b>
+
+```
+li = [[1, 4], [2, 1], [3, 9], [4, 2], [4, 5]]
+
+sorted(li, key=lambda l: l[1])
+```
+
+or
+
+```
+li.sort(key=lambda l: l[1)
+```
+</b></details>
+
 <details>
 <summary>Combine [1, 2, 3] and ['x', 'y', 'z'] so the result is [(1, 'x'), (2, 'y'), (3, 'z')]</summary><br><b>
 
@@ -3344,16 +3398,6 @@ Using the re module
 <summary>How to find all the IP addresses in a variable? How to find them in a file?</summary><br><b>
 </b></details>
 
-<details>
-<summary>Sort a list of lists by the second item of each nested list</summary><br><b>
-
-```
-li = [[1, 4], [2, 1], [3, 9], [4, 2], [4, 5]]
-
-sorted(x, key=lambda l: l[1])
-```
-</b></details>
-
 <details>
 <summary>You have the following list: <code>[{'name': 'Mario', 'food': ['mushrooms', 'goombas']}, {'name': 'Luigi', 'food': ['mushrooms', 'turtles']}]</code>
   Extract all type of foods. Final output should be: {'mushrooms', 'goombas', 'turtles'}</summary><br><b>
@@ -3442,12 +3486,6 @@ Detailed answer can be found here: http://codingshell.com/python-all-string-perm
 
 <details>
 <summary>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)</summary><br><b>
-
-```
-matrix = "1 2 3\n4 5 6\n7 8 9"
-rows = [ [int(x) for x in li if x != ' '] for li in matrix.split("\n")]
-colums = list(zip(*(rows)))
-```
 </b></details>
 
 <details>
@@ -3665,6 +3703,20 @@ What would be the result of is_int(2) and is_int(False)?
 <summary>What is your experience with writing tests in Python?</summary><br><b>
 </b></details>
 
+<details>
+<summary>What is PEP8? Give an example of 3 style guidelines</summary><br><b>
+
+PEP8 is a list of coding conventions and style guidelines for Python
+
+5 style guidelines:
+
+    1. Limit all lines to a maximum of 79 characters.
+    2. Surround top-level function and class definitions with two blank lines.
+    3. Use commas when making a tuple of one element
+    4. Use spaces (and not tabs) for indentation
+    5. Use 4 spaces per indentation level
+</b></details>
+
 <details>
 <summary>How would you check if two strings are equal? What about booleans?</summary><br><b>
 </b></details>