update

README.md

@@ -152,6 +152,7 @@ Name | Description
 [opensource.com](https://opensource.com) | open source related articles including DevOps
 [CooperPress](https://cooperpress.com/publications) | various newsletters on different topics
 [afreshcup](https://afreshcup.com) | "covering Ruby on Rails and whatever else I find interesting in the universe of software"
+[thisweekindevops.com](https://thisweekindevops.com) | "DevOps news without the hype"
 
 ## Articles
 

resources/docker.md

@@ -22,3 +22,4 @@ Name | Comments
 * Stop and remove all containers: `docker container stop $(docker container ls -aq)`
 * Run container with bash shell: `docker run -ti ubuntu:latest bash`
 * Check how many containers are running: `docker info`
+* Cleanup everything: `docker system prune -a -f`

resources/elk.md

@@ -67,7 +67,8 @@ PUT test_index/_settings
 }
 ```
 
-* Delete index: `DELETE /<index_name>`
+* Delete index from console UI: `DELETE /<index_name>`
+* Delete all indexes from CLI: `curl -X DELETE 'http://<elasticsearch_address>:9200/_all` # Don't run this! it will delete also the Kibana index and you'll not have default space available
 
 * Create cluster
 

resources/kubernetes.md

@@ -17,6 +17,7 @@ Name | Comments
 Name | Comments
 :------ |:--------:
 [Kubernetes Networking](https://github.com/nleiva/kubernetes-networking-links) | Kubernetes Networking Resources
+[Liveness and Readiness Probes](https://www.openshift.com/blog/liveness-and-readiness-probes) |
 
 ## Misc
 
@@ -41,6 +42,12 @@ Name | Comments
 [Kubesort](https://github.com/AATHITH/kubesort) | "kubesort helps you sort the results from kubectl get in an easy way"
 [IngressMonitorController](https://github.com/stakater/IngressMonitorController) | "A Kubernetes controller to watch ingresses and create liveness alerts for your apps/microservices"
 
+## Certificates
+
+Name | Comments
+:------ |:--------:
+[CKAD-Practice-Questions](https://github.com/bbachi/CKAD-Practice-Questions) | "a consolidated list for CKAD practice questions"
+
 ## CheatSheet
 
 ### Minikube

resources/linux.md

@@ -2,14 +2,20 @@
 
 <div align="center"><img src="../images/linux_map.png"></div><hr/>
 
-## Learn Linux - Articles and Guides
+## Learn Linux - Tutorials and Guides
 
 Name | Comments
 :------|:------:
 [Linux Journey](https://linuxjourney.com) | Written guides + exercises + quiz
 [Techmint Linux](https://www.tecmint.com/free-online-linux-learning-guide-for-beginners) | Written articles/lessons
 [Linux Survival](https://linuxsurvival.com/linux-tutorial-introduction) | Interactive guide
 
+## Learn Linux - Articles
+
+Name | Comments
+:------|:------:
+[Linux Filesystem Explained](https://www.linux.com/training-tutorials/linux-filesystem-explained) | NSIA
+
 ## Linux Deep Dive - Articles
 
 Name | Comments

resources/mongo.md

@@ -6,3 +6,45 @@ Name | Description
 :------|:------:
 [Guru99 MongoDB Tutorial](https://www.guru99.com/what-is-mongodb.html) | MongoDB Tutorial
 [Tutorialspoint Tutorial](https://www.tutorialspoint.com/mongodb) | MongoDB Tutorial
+
+## Cheat Sheet
+
+### Mongo Shell
+
+I assume the following for the purpose of the examples:
+  * DB name: usage_patterns
+  * Collection name: accounts
+
+* DB stats: `db.stats()`
+* Switch to a DB: `use usage_patterns`
+
+* show collections: `show collections`
+* Count the number of documents in a collection: `db.accounts.count()`
+* Remove all the documents from a collection: `db.accounts.remove({})`
+
+* Export Mongo DB into JSON file: `mongoexport --db=usage_patterns --collection=accounts --out=data.json`
+
+#### Aggregations
+
+* Count the number of documents: `db.accounts.aggregate([ { "$count": "number of documents" }])`
+* Show only the sub element "attachment_uuids": `db.accounts.aggregate( [ {$project: {"hosts.attachment_uuids": 1, _id:0}} ] )`
+
+### Mongo Python
+
+* Add new element to an arrray only if it doesn't exists already
+
+```
+mongo_client.update(
+        { "account_number": account_num },
+        { "$addToSet": { "hosts": {'hostname': hostname} } }
+    )
+```
+
+* Add a new element to an array in sub-document (if it doesn't exists already):
+
+```
+ mongo_client.update_one(
+        { "account_number": account_num, "hosts.hostname": hostname },
+        { "$addToSet": { "hosts.$.attachment_uuids": attachment_uuid } }
+    )
+```