Add Argo and k8s questions

Also updated Datadog questions.

README.md

@@ -2,7 +2,7 @@
 
 :information_source:  This repo contains questions and exercises on various technical topics, sometimes related to DevOps and SRE
 
-:bar_chart:  There are currently **2466** exercises and questions
+:bar_chart:  There are currently **2487** exercises and questions
 
 :warning:  You can use these for preparing for an interview but most of the questions and exercises don't represent an actual interview. Please read [FAQ page](faq.md) for more details
 

topics/argo/README.md

@@ -5,7 +5,8 @@
     - [ArgoCD 101](#argocd-101)
     - [ArgoCD Secrets](#argocd-secrets)
     - [ArgoCD Helm](#argocd-helm)
-  - [Argo Questions](#argo-questions)
+    - [Argo Rollouts](#argo-rollouts)
+  - [ArgoCD Questions](#argocd-questions)
     - [ArgoCD 101](#argocd-101-1)
     - [Practical ArgoCD 101](#practical-argocd-101)
       - [CLI](#cli)
@@ -14,6 +15,9 @@
     - [ArgoCD Application Health](#argocd-application-health)
     - [ArgoCD Syncs](#argocd-syncs)
     - [ArgoCD and Helm](#argocd-and-helm)
+  - [Argo Rollouts Questions](#argo-rollouts-questions)
+    - [Argo Rollouts 101](#argo-rollouts-101)
+    - [Argo Rollouts Commands](#argo-rollouts-commands)
 
 ## ArgoCD Exercises
 
@@ -37,7 +41,14 @@
 |--------|--------|------|----|----|
 | Helm ArgoCD App | Secrets | [Exercise](exercises/argocd_helm_app/exercise.md) | [Solution](exercises/argocd_helm_app/solution.md)
 
-## Argo Questions
+### Argo Rollouts
+
+|Name|Topic|Objective & Instructions|Solution|Comments|
+|--------|--------|------|----|----|
+| Blue/Green Rollout | Rollouts | [Exercise](exercises/blue_green_rollout/exercise.md) | [Solution](exercises/blue_green_rollout/solution.md)
+| Canary Rollout | Rollouts | [Exercise](exercises/canary_rollout/exercise.md) | [Solution](exercises/canary_rollout/solution.md)
+
+## ArgoCD Questions
 
 ### ArgoCD 101
 
@@ -340,4 +351,62 @@ ArgoCD is able to track packaged Helm chart in a sense where it will monitor for
 <summary>True or False? When ArgoCD tracks Helm chart the chart is no longer an Helm application and it's a ArgoCD app</summary><br><b>
 
 True. Trying to execute commands like `helm ls` will fail because helm metadata doesn't exist anymore and the application is tracked as ArgoCD app.
+</b></details>
+
+## Argo Rollouts Questions
+
+### Argo Rollouts 101
+
+<details>
+<summary>What is Argo Rollouts?</summary><br><b>
+
+A controller for Kubernetes to perform application deployments using different strategies like Blue/Green deployments, Canary deployments, etc.
+
+In addition, it supports A/B tests, automatic rollbacks and integrated metric analysis.
+</b></details>
+
+<details>
+<summary>What happens when you rollout a new version of your app with argo rollouts?</summary><br><b>
+
+- Argo Rollouts creates a new replicaset (that is the new app version)
+  - Old version is still alive
+- ArgoCD marks the app as out-ofsync 
+</b></details>
+
+### Argo Rollouts Commands
+
+<details>
+<summary>How to list rollouts?</summary><br><b>
+
+`kubectl argo rollouts list rollouts`
+</b></details>
+
+<details>
+<summary>How to list the rollouts of a given application?</summary><br><b>
+
+`kubectl argo rollouts get rollout SOME-APP`
+</b></details>
+
+<details>
+<summary>How to check the status of a rollout?</summary><br><b>
+
+`kubectl argo rollouts status SOME-APP`
+</b></details>
+
+<details>
+<summary>How to rollout a new version (with new container tag)?</summary><br><b>
+
+`kubectl argo rollouts set image SOME-APP web-app=some/registry/and/image:v2.0`
+</b></details>
+
+<details>
+<summary>How to manually promote to new app version?</summary><br><b>
+
+`kubectl argo rollouts promote SOME-APP`
+</b></details>
+
+<details>
+<summary>How do you monitor a rollout?</summary><br><b>
+
+`kubectl argo rollouts get rollout SOME-APP --watch`
 </b></details>

topics/argo/exercises/blue_green_rollout/exercise.md

@@ -0,0 +1,21 @@
+# Argo Rollouts - Blue/Green
+
+## Requirements
+
+1. Running Kubernetes cluster
+2. Argo Rollouts CLI
+3. Deployed app in specific version
+
+## Objectives
+
+1. Install Argo Rollouts controller
+2. Write a rollout manifest that use blue/green deployment and apply it
+   1. Set it to 3 replicas
+   2. Disable auto-promotions
+3. Check the rollout list
+4. Rollout a new version of your app in any way you prefer
+   1. Check the status of the rollout
+
+## Solutions
+
+Click [here](solution.md) to view the solution.

topics/argo/exercises/blue_green_rollout/solution.md

@@ -0,0 +1,58 @@
+# Argo Rollouts - Blue/Green
+
+## Requirements
+
+1. Running Kubernetes cluster
+2. Argo Rollouts CLI
+3. Deployed app in specific version
+
+## Objectives
+
+1. Install Argo Rollouts controller
+2. Write a rollout manifest that use blue/green deployment and apply it
+   1. Set it to 3 replicas
+   2. Disable auto-promotions
+3. Check the rollout list
+4. Rollout a new version of your app in any way you prefer
+   1. Check the status of the rollout
+
+## Solution
+
+Installation:
+
+1. `kubectl create namespace argo-rollouts`
+   1. `kubectl apply -n argo-rollouts -f https://github.com/argoproj/argo-rollouts/releases/latest/download/install.yaml`
+
+2. Rollout resource:
+
+```
+---
+apiVersion: argoproj.io/v1alpha1
+kind: Rollout
+metadata:
+  name: some-app
+spec:
+  replicas: 3
+  strategy:
+    blueGreen:     
+      autoPromotionEnabled: false
+  selector:
+    matchLabels:
+      app: some-web-app
+  template:
+    metadata:
+      labels:
+        app: some-web-app
+    spec:
+      containers:
+      - name: web-app
+        image: some/registry/and/image:v1.0
+        ports:
+        - name: http
+          containerPort: 8080
+          protocol: TCP
+```
+
+3. `kubectl argo rollouts list rollouts`
+4. `kubectl argo rollouts set image SOME-APP web-app=some/registry/and/image:v2.0`
+   1. `kubectl argo rollouts get rollout some-app --watch`

topics/argo/exercises/canary_rollout/exercise.md

@@ -0,0 +1,21 @@
+# Argo Rollouts - Canary
+
+## Requirements
+
+1. Running Kubernetes cluster
+2. Argo Rollouts CLI
+3. Deployed app in a specific version
+
+## Objectives
+
+1. Install Argo Rollouts controller
+2. Write a rollout manifest that use canary rollout strategy and apply it
+   1. Set it to 3 replicas
+   2. Disable auto-promotions
+3. Check the rollout list
+4. Rollout a new version of your app in any way you prefer
+   1. Check the status of the rollout
+
+## Solutions
+
+Click [here](solution.md) to view the solution.

topics/argo/exercises/canary_rollout/solution.md

@@ -0,0 +1,70 @@
+# Argo Rollouts - Canary
+
+## Requirements
+
+1. Running Kubernetes cluster
+2. Argo Rollouts CLI
+3. Deployed app in a specific version
+
+## Objectives
+
+1. Install Argo Rollouts controller
+2. Write a rollout manifest that use canary rollout strategy and apply it
+   1. Set it to 6 replicas
+   2. Disable auto-promotions
+3. Check the rollout list
+4. Rollout a new version of your app in any way you prefer
+   1. Check the status of the rollout
+
+## Solution
+
+Installation:
+
+1. `kubectl create namespace argo-rollouts`
+   1. `kubectl apply -n argo-rollouts -f https://github.com/argoproj/argo-rollouts/releases/latest/download/install.yaml`
+
+2. Rollout resource:
+
+```
+---
+apiVersion: argoproj.io/v1alpha1
+kind: Rollout
+metadata:
+  name: some-app
+spec:
+  replicas: 6
+  strategy:
+    canary:
+      stableService: k8s-service-stable
+      canaryService: k8s-service-canary
+      trafficRouting:
+        ambassador:
+          mappings:
+            - k8s-mapping
+      steps:
+      - setWeight: 30
+      - pause: {}
+      - setWeight: 60
+      - pause: {}
+      - setWeight: 100
+      - pause: {}   
+  selector:
+    matchLabels:
+      app: some-web-app
+  template:
+    metadata:
+      labels:
+        app: some-web-app
+    spec:
+      containers:
+      - name: web-app
+        image: some/registry/and/image:v1.0
+        ports:
+        - name: http
+          containerPort: 8080
+          protocol: TCP
+```
+
+3. `kubectl argo rollouts list rollouts`
+4. `kubectl argo rollouts set image SOME-APP web-app=some/registry/and/image:v2.0`
+   1. `kubectl argo rollouts get rollout some-app --watch`

topics/datadog/README.md

@@ -3,6 +3,8 @@
 - [DataDog](#datadog)
   - [Questions](#questions)
     - [Basics](#basics)
+  - [Datadog Agent](#datadog-agent)
+  - [Datadog Integrations](#datadog-integrations)
 
 ## Questions
 
@@ -41,8 +43,37 @@ Basically any device or location that has Datadog agent installed and running on
 
 <details>
 <summary>What is a Datadog agent?</summary><br><b>
+
+A software runs on a Datadog host. Its purpose is to collect data from the host and sent it to Datadog (data like metrics, logs, etc.)
 </b></details>
 
 <details>
-<summary>What are Datadog agents?</summary><br><b>
+<summary>What are Datadog tags?</summary><br><b>
+
+Datadog tags are used to mark different information with unique properties. For example, you might want to tag some data with "environment: production" while tagging information from staging or dev environment with "environment: staging".
+</b></details>
+
+## Datadog Agent
+
+<details>
+<summary>What are the component of a Datadog agent?</summary><br><b>
+
+* Collector: its role is to collect data from the host on which it's installed. The default period of time as of today is every 15 seconds.
+* Forwarder: responsible for sending the data to Datadog over HTTPS
+</b></details>
+
+## Datadog Integrations
+
+
+<details>
+<summary>What can you tell about Datadog integrations?</summary><br><b>
+
+- Datadog has many supported integrations with different services, platforms, etc.
+- Each integration includes information on how to apply it, how to use it and what configuration options it supports
+</b></details>
+
+<details>
+<summary>What opening some of the integrations windows/pages, there is a ection called "Monitors". What can be found there?</summary><br><b>
+
+Usually you can find there some anomaly types that Datadog suggests to monitor and track.
 </b></details>

topics/kubernetes/README.md

@@ -17,6 +17,7 @@ What's your goal?
     - [ReplicaSet](#replicaset)
     - [Labels and Selectors](#labels-and-selectors)
     - [Scheduler](#scheduler)
+    - [Kustomize](#kustomize)
   - [Kubernetes Questions](#kubernetes-questions)
     - [Kubernetes 101](#kubernetes-101)
     - [Cluster and Architecture](#cluster-and-architecture)
@@ -64,6 +65,8 @@ What's your goal?
     - [Resource Limits](#resource-limits)
       - [Resources Limits - Commands](#resources-limits---commands)
     - [Monitoring](#monitoring)
+    - [Kustomize](#kustomize-1)
+    - [Deployment Strategies](#deployment-strategies)
     - [Scenarios](#scenarios)
 
 ## Kubernetes Exercises
@@ -103,6 +106,12 @@ What's your goal?
 |--------|--------|------|----|----|
 | Taints 101 | Taints | [Exercise](exercises/taints_101/exercise.md) | [Solution](exercises/taints_101/solution.md)
 
+### Kustomize
+
+|Name|Topic|Objective & Instructions|Solution|Comments|
+|--------|--------|------|----|----|
+| common labels | Kustomize | [Exercise](exercises/kustomize_common_labels/exercise.md) | [Solution](exercises/kustomize_common_labels/solution.md)
+
 ## Kubernetes Questions
 
 ### Kubernetes 101
@@ -3006,6 +3015,103 @@ TODO: add more monitoring solutions
 
 </b></details>
 
+### Kustomize
+
+<details>
+<summary>What is Kustomize?</summary><br><b>
+</b></details>
+
+<details>
+<summary>Explain the need for Kustomize by describing actual use cases</summary><br><b>
+
+* You have an helm chart of an application used by multiple teams in your organization and there is a requirement to add annotation to the app specifying the name of the of team owning the app
+  * Without Kustomize you would need to copy the files (chart template in this case) and modify it to include the specific annotations we need
+  * With Kustomize you don't need to copy the entire repo or files
+* You are asked to apply a change/patch to some app without modifying the original files of the app
+  * With Kustomize you can define kustomization.yml file that defines these customizations so you don't need to touch the original app files
+</b></details>
+
+<details>
+<summary>Describe in high-level how Kustomize works</summary><br><b>
+
+1. You add kustomization.yml file in the folder of the app you would like to customize.
+   1. You define the customizations you would like to perform
+2. You run `kustomize build APP_PATH` where your kustomization.yml also resides
+</b></details>
+
+### Deployment Strategies
+
+<details>
+<summary>What rollout/deployment strategies are you familiar with?</summary><br><b>
+
+* Blue/Green Deployments: You deploy a new version of your app, while old version still running, and you start redirecting traffic to the new version of the app
+* Canary Deployments: You deploy a new version of your app and start redirecting **portion** of your users/traffic to the new version. So you the migration to the new version is much more gradual
+</b></details>
+
+<details>
+<summary>Explain Blue/Green deployments/rollouts in detail</summary><br><b>
+
+Blue/Green deployment steps:
+
+1. Traffic coming from users through a load balancer to the application which is currently version 1
+
+Users -> Load Balancer -> App Version 1
+
+2. A new application version 2 is deployed (while version 1 still running)
+
+Users -> Load Balancer -> App Version 1
+                          App Version 2
+
+3. If version 2 runs properly, traffic switched to it instead of version 1
+
+User -> Load Balancer     App version 1
+                       -> App Version 2
+
+4. Whether old version is removed or keep running but without users being redirected to it, is based on team or company decision
+
+Pros:
+  * We can rollback/switch quickly to previous version at any point
+Cons:
+  * In case of an issue with new version, ALL users are affected (instead of small portion/percentage)
+
+</b></details>
+
+<details>
+<summary>Explain Canary deployments/rollouts in detail</summary><br><b>
+
+Canary deployment steps:
+
+1. Traffic coming from users through a load balancer to the application which is currently version 1
+
+Users -> Load Balancer -> App Version 1
+
+2. A new application version 2 is deployed (while version 1 still running) and part of the traffic is redirected to the new version
+
+Users -> Load Balancer ->(95% of the traffic) App Version 1
+                       ->(5% of the traffic) App Version 2
+
+3. If the new version (2) runs well, more traffic is redirected to it
+
+Users -> Load Balancer ->(70% of the traffic) App Version 1
+                       ->(30% of the traffic) App Version 2
+
+3. If everything runs well, at some point all traffic is redirected to the new version
+
+Users -> Load Balancer -> App Version 2
+
+
+Pros:
+  * If there is any issue with the new deployed app version, only some portion of the users affected, instead of all of them
+Cons:
+  * Testing of new version is neccesrialy in the production environment (as the user traffic is exists only there)
+
+</b></details>
+
+<details>
+<summary>What ways are you familiar with to implement deployment strategies (like canary, blue/green) in Kubernetes?</summary><br><b>
+
+There are multiple ways. One of them is Argo Rollouts.
+</b></details>
 
 ### Scenarios
 

topics/kubernetes/exercises/kustomize_common_labels/exercise.md

@@ -0,0 +1,17 @@
+# Kustomize - Common Labels
+
+## Requirements
+
+1. Running Kubernetes cluster
+2. Kustomize binary installed
+
+## Objectives
+
+In the current directory there is an app composed of a Deployment and Service.
+
+1. Write a kustomization.yml file that will add to both the Service and Deployment the label "team-name: aces"
+2. Execute a kustomize command that will generate the customized k8s files with the label appended
+
+## Solution
+
+Click [here](solution.md) to view the solution

topics/kubernetes/exercises/kustomize_common_labels/solution.md

@@ -0,0 +1,31 @@
+# Kustomize - Common Labels
+
+## Requirements
+
+1. Running Kubernetes cluster
+2. Kustomize binary installed
+
+## Objectives
+
+In the current directory there is an app composed of a Deployment and Service.
+
+1. Write a kustomization.yml file that will add to both the Service and Deployment the label "team-name: aces"
+2. Execute a kustomize command that will generate the customized k8s files with the label appended
+
+## Solution
+
+1. Add the following to kustomization.yml in someApp directory:
+
+```
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+commonLabels:
+  team-name: aces
+
+resources:
+  - service.yml
+  - deployment.yml
+```
+
+2. Run `kustomize build someApp`

topics/kubernetes/exercises/kustomize_common_labels/someApp/deployment.yml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+  labels:
+    app: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.14.2
+        ports:
+        - containerPort: 80

topics/kubernetes/exercises/kustomize_common_labels/someApp/service.yml

@@ -0,0 +1,11 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: my-service
+spec:
+  selector:
+    app: nginx
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 9376