Merge branch 'master' into master

README.md

@@ -1,4 +1,4 @@
-# Certified Kuberentes Administartor (CKA) Course
+# Certified Kubernetes Administrator (CKA) Course
 
 These are notes from the [Certified Kubernetes Administrator Course](https://kodekloud.com/courses/enrolled/539883) hosted on KodeKloud.
 
@@ -248,4 +248,4 @@ These are notes from the [Certified Kubernetes Administrator Course](https://kod
   - [03-Mock-Exam-2](docs/14-Mock-Exams/03-Mock-Exam-2.md)
   - [04-CKA-MockExam-2-Solution](docs/14-Mock-Exams/04-CKA-MockExam-2-Solution.md)
   - [05-Mock-Exam-3](docs/14-Mock-Exams/05-Mock-Exam-3.md)
-  - [06-CKA-MockExam-3-Solution](docs/14-Mock-Exams/06-CKA-MockExam-3-Solution.md)
+  - [06-CKA-MockExam-3-Solution](docs/14-Mock-Exams/06-CKA-MockExam-3-Solution.md)

docs/01-Introduction/01-Course-Introduction.md

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+# Course Introduction
+
+  - Take me to the [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9808050)
+
+#### This course focuses on Administration part of the kubernetes. 
+
+## Course Structure
+
+   - Lectures
+   - Demos
+   - Quizzes
+   - Practice Questions
+   - Q & A Section
+
+## Pre-Requisites
+
+   - Docker
+   - Basics of kubernetes
+     - PODS, Deployments, Services ...
+   - YAML
+   - Setting up a basic lab environment with VirtualBox
+
+#### If you are a beginner we highly recommend Kubenetes for the Absolute Beginners Hands-On course
+
+   - Take me to the [Kubenetes for the Absolute Beginners Hands-On Course](https://kodekloud.com/courses/enrolled/316262)
+
+## Course Objectives
+
+The objectives of this course are aligned to match the **`Certified Kubernetes Administration Exam (CKA)`**
+
+- Core Concepts
+  - Cluster Architecture
+  - API Primitives
+  - Services & Other Network Primitives
+- Scheduling
+  - Labels & Selectors
+  - Daemon Sets
+  - Resource Limits
+  - Multiple Schedulers
+  - Manual Scheduling
+  - Scheduler Events
+  - Configure Kubernetes Scheduler
+- Logging & Monitoring
+  - Monitor Cluster Components
+  - Monitor Cluster Components Logs
+  - Monitor Applications
+  - Application Logs
+- Application Lifecycle Management
+  - Rolling Updates and Rollbacks in Deployments
+  - Configuring Applications
+  - Scale Applications
+  - Self-Healing Applications
+- Cluster Maintenance
+  - Cluster Upgrade Process
+  - Operating System Upgrades
+  - Backup and Restore Methodologies
+ - Security
+   - Authentication & Authorization
+   - Kubernetes Security
+   - Network Policies
+   - TLS Certificates for Cluster Components
+   - Image Security
+   - Network Polices
+   - Security Contexts
+   - Secure Persistent Key Value Store
+- Storage
+  - Persistent Volumes
+  - Access Modes for Volumes
+  - Persistent Volume Claims
+  - Kubernetes Storage Object
+  - Configure Applications with Persistent Storage
+- Networking
+  - Pre-Requisites - Network, Switching, Routing, Tools 
+  - Pre-Requisites - Network Namespaces
+  - Pre-Requisites - Networking in Docker
+  - Networking Configuration on Cluster Nodes
+  - Service Networking
+  - POD Networking Concepts
+  - Network Loadbalancer
+  - Ingress
+  - Cluster DNS
+  - CNI
+- Installation, Configuration & Validation
+  - Design a Kubernetes Cluster
+  - Install Kubnernetes Master and Nodes
+  - Secure Cluster Communication
+  - HA Kubernetes Cluster
+  - Kubenetes Release Binaries
+  - Provision Infrastructure
+  - Choose a Network Solution
+  - Kubernetes Infrastructure Config
+  - Run & Analyze end-to-end test
+  - Node end-to-end tests
+- Troubleshooting
+  - Application Failure
+  - Control Plane Failure
+  - Worker Node Failure
+  - Networking
+
+## Practice Tests
+
+CKA exam is a practical hands-on exam it is very important to practice what you learn. Which is why we build a custom solution that will give you access to a **`Real Kubernetes Environment`** right in your browser along with **`Quiz Portal`**
+
+## Kubernetes the hardway
+
+   - Take me to [Kubernetes The Hardway on VirtualBox](https://github.com/mmumshad/kubernetes-the-hard-way)

docs/01-Introduction/02-Certification.md

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+# Certification
+
+  - Take me to [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9814246)
+
+## Certification Details
+
+   - **`Certified Kubernetes Administrator`**: https://www.cncf.io/certification/cka/
+
+   - **`Exam Curriculum (Topics)`**: https://github.com/cncf/curriculum
+
+   - **`Candidate Handbook`**: https://www.cncf.io/certification/candidate-handbook
+
+   - **`Exam Tips`**: http://training.linuxfoundation.org/go//Important-Tips-CKA-CKAD
+
+#### Use the code - KUBERNETES15 - while registering for the CKA or CKAD exams at Linux Foundation to get a 15% discount.
+

docs/02-Core-Concepts/01-Core-Concepts-Section-Introduction.md

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+# Core Concepts Section Introduction
+
+ - Take me to the [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9808147)
+
+In this section, we will take a look at the below
+- Cluster Architecture  
+- API Primitives
+- Services & Other Network Primitives
+
+k8s reference docs:
+- https://kubernetes.io/docs/concepts/overview/kubernetes-api/
+- https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/
+- https://kubernetes.io/docs/concepts/architecture/
+- https://kubernetes.io/docs/concepts/overview/components/
+- https://kubernetes.io/docs/concepts/services-networking/
+

docs/02-Core-Concepts/02-Cluster-Architecture.md

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+# Cluster Architecture
+
+  - Take me to [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9808145)
+
+In this section , we will take a look at the kubernetes Architecture at high level.
+- 10,000 Feet Look at the Kubernetes Architecture
+
+  ![Kubernetes Architecture](../../images/k8s-arch.PNG)
+
+  ![Kubernetes Architecture 1](../../images/k8s-arch1.PNG)
+
+K8s Reference Docs:
+- https://kubernetes.io/docs/concepts/architecture/

docs/02-Core-Concepts/03-ETCD-For-Beginners.md

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+# ETCD for Beginners
+  - Take me to the [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9808166)
+
+  In this section, we will take a quick look at introduction to ETCD for beginners. 
+  - What is ETCD?
+  - What is a Key-Value Store?
+  - How to get started quickly with ETCD?
+  - How to operate ETCD?
+
+ ## What is a ETCD?
+     - ETCD is a distributed reliable key-value store that is simple, secure & Fast.
+     
+## What is a Key-Value Store
+   - Traditionally, databases have been in tabular format, you must have heared about SQL or Relational databases. They store data in rows and columns
+
+     ![relational-dbs](../../images/relational-dbs.PNG)
+
+   - A Key-Value Store stores information in a Key and Value format.
+
+     ![key-value](../../images/key-value.PNG)
+
+     ![key-value1](../../images/key-value1.PNG)
+
+     ![key-value2](../../images/key-value2.PNG)
+
+     ![key-value3](../../images/key-value3.PNG)
+
+## Install ETCD
+   - Its easy to install and get started with **`ETCD`**.
+     - Download the relevant binary for your operating system from github releases page (https://github.com/etcd-io/etcd/releases)
+       ```
+       For Example: To download ETCD V3.3.11, run the below curl command
+         
+       $ https://github.com/etcd-io/etcd/releases/download/v3.3.11/etcd-v3.3.11-linux-amd64.tar.gz
+       ```
+     - Extract it.
+       ```
+       $ tar xvzf etcd-v3.3.11-linux-amd64.tar.gz 
+       ```
+     - Run the ETCD Service
+       ```
+       $ ./etcd
+       ```
+     - When you start **`ETCD`** it will by default listens on port **`2379`**
+      - The default client that comes with **`ETCD`** is the **`etcdct`** client. You can use it to store and retrieve key-value pairs.
+        ```
+        Syntax: To Store a Key-Value pair
+        $ ./etcdctl set key1 value1
+        ```
+        ```
+        Syntax: To retrieve the stored data
+        $ ./etcdctl get key1
+        ```
+        ```
+        Syntax: To view more commands. Run etcdctl without any arguments
+        $ ./etcdctl
+        ```
+        
+        ![etcdctl](../../images/etcdctl.PNG)
+        
+       K8s Reference Docs:
+       - https://kubernetes.io/docs/concepts/overview/components/
+       - https://etcd.io/docs/
+       - https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/
+       

docs/02-Core-Concepts/04-ETCD-in-Kubernetes.md

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+# ETCD in Kubernetes
+  - Take me to [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9808160)
+
+In this section, we will take a look at ETCD role in kubernetes
+
+## ETCD Datastore
+- The ETCD Datastore stores information regarding the cluster such as **`Nodes`**, **`PODS`**, **`Configs`**, **`Secrets`**, **`Accounts`**, **`Roles`**, **`Bindings`** and **`Others`**.
+- Every information you see when you run the **`kubectl get`** command is from the **`ETCD Server`**.
+
+## Setup - Manual
+- If you setup your cluster from scratch then you deploy **`ETCD`** by downloading ETCD Binaries yourself
+- Installing Binaries and Configuring ETCD as a service in your master node yourself.
+  ```
+  $ wget -q --https-only "https://github.com/etcd-io/etcd/releases/download/v3.3.11/etcd-v3.3.11-linux-amd64.tar.gz"
+  ```
+
+  ![etcd](../../images/etcd.PNG)
+
+## Setup - Kubeadm
+- If you setup your cluster using **`kubeadm`** then kubeadm will deploy etcd server for you as a pod in **`kube-system`** namespace.
+  ```
+  $ kubectl get pods -n kube-system
+  ```
+  ![etcd1](../../images/etcd1.PNG)
+
+## Explore ETCD
+- To list all keys stored by kubernetes, run the below command
+  ```
+  $ kubectl exec etcd-master -n kube-system etcdctl get / --prefix -key
+  ```
+- Kubernetes Stores data in a specific directory structure, the root directory is the **`registry`** and under that you have varies kubernetes constructs such as **`minions`**, **`nodes`**, **`pods`**, **`replicasets`**, **`deployments`**, **`roles`**, **`secrets`** and **`Others`**.
+
+  ![etcdctl1](../../images/etcdctl1.PNG)
+
+## ETCD in HA Environment
+   - In a high availability environment, you will have multiple master nodes in your cluster that will have multiple ETCD Instances spread across the master nodes.
+   - Make sure etcd instances know each other by setting the right parameter in the **`etcd.service`** configuration. The **`--initial-cluster`** option where you need to specify the different instances of the etcd service.
+     ![etcd-ha](../../images/etcd-ha.PNG)
+
+K8s Reference Docs:
+- https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/
+- https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/setup-ha-etcd-with-kubeadm/
+- https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/high-availability/#stacked-control-plane-and-etcd-nodes
+- https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/high-availability/#external-etcd-nodes

docs/02-Core-Concepts/05-Kube-API-Server.md

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+# Kube API Server
+  - Take me to [Video Tutorial](https://kodekloud.com/courses/539883/lectures/9808163)
+
+In this section, we will talk about kube-apiserver in kubernetes
+
+#### Kube-apiserver is the primary component in kubernetes.
+- Kube-apiserver is responsible for **`authenticating`**, **`validating`** requests, **`retrieving`** and **`Updating`** data in ETCD key-value store. In fact kube-apiserver is the only component that interacts directly to the etcd datastore. The other components such as kube-scheduler, kube-controller-manager and kubelet uses the API-Server to update in the cluster in thier respective areas.
+
+  ![post](../../images/post.PNG)
+
+## Installing kube-apiserver
+
+- If you are bootstrapping kube-apiserver using **`kubeadm`** tool, then you don't need to know this, but if you are setting up using the hardway then kube-apiserver is available as a binary in the kubernetes release page.
+  - For example: You can downlaod the kube-apiserver v1.13.0 binary here [kube-apiserver](https://storage.googleapis.com/kubernetes-release/release/v1.13.0/bin/linux/amd64/kube-apiserver)
+    ```
+    $ wget https://storage.googleapis.com/kubernetes-release/release/v1.13.0/bin/linux/amd64/kube-apiserver
+    ```
+ 
+ ![kube-apiserver](../../images/kube-apiserver.PNG)
+ 
+## View kube-apiserver - Kubeadm
+- kubeadm deploys the kube-apiserver as a pod in kube-system namespace on the master node.
+  ```
+  $ kubectl get pods -n kube-system
+  ```
+   
+  ![kube-apiserver1](../../images/kube-apiserver1.PNG)
+   
+## View kube-apiserver options - Kubeadm
+- You can see the options with in the pod defination file located at **`/etc/kubernetes/manifests/kube-apiserver.yaml`**
+  ```
+  $ cat /etc/kubernetes/manifests/kube-apiserver.yaml
+  ```
+  
+  ![kube-apiserver2](../../images/kube-apiserver2.PNG)
+   
+## View kube-apiserver options - Manual
+- In a Non-kubeadm setup, you can inspect the options by viewing the kube-apiserver.service
+  ```
+  $ cat /etc/systemd/system/kube-apiserver.service
+  ```
+  
+  ![kube-apiserver3](../../images/kube-apiserver3.PNG)
+   
+- You can also see the running process and affective options by listing the process on master node and searching for kube-apiserver.
+  ```
+  $ ps -aux |grep kube-apiserver
+  ```
+  ![kube-apiserver4](../../images/kube-apiserver4.PNG)
+
+K8s Reference Docs:
+- https://kubernetes.io/docs/reference/command-line-tools-reference/kube-apiserver/
+- https://kubernetes.io/docs/concepts/overview/components/
+- https://kubernetes.io/docs/concepts/overview/kubernetes-api/
+- https://kubernetes.io/docs/tasks/access-application-cluster/access-cluster/
+- https://kubernetes.io/docs/tasks/administer-cluster/access-cluster-api/