vault backup: 2025-08-16 13:44:43

temporary.md

@@ -20,7 +20,21 @@ For a weak, dont do things you know are vad and do things you know are good for
 Learn traffic rules
 Earn IBM Fullstack developer certificate (but afte)
 
+- Suggested IDE: vscode
+	- YAML extension by Red Hat, configure in the extension settings the YAML schema and set this in the settings.json: `"yaml.schemas": {
 
+        "kubernetes": "*.yaml"
+
+    }`
+	- restart the IDE afterwards
+- kubectl
+	- `kubectl run nginx --image=nginx` will fetch the nginx image from docker hub and create a pod
+	- `kubectl create deployment nginx --image=nginx` creates a deployment
+	- `kubectl create -f pod-definition.yml` create from file (`kubectl apply -f file.yml` works too?)
+	- `kubectl get pods`
+	- `kubectl describe pod myapp-pod`
+- scaling: we create additional pods. a pod can contain multiple containers but one pod shall only contain what is necessary for one instance of the application. we do NOT create additional containers in the same pod
+- minikube: bundles master node programs and node programs on one machine. requires virtualization (via hypervisor KVM, VirtualBox... or docker but latter is not recommended)
 - ctr: CLI for containerD, not very user friendly and mostly for debugging
 	- It is advised to use nerdctl instead
 - nerdctl: provides docker-like CLI for containerd, supports docker compose, supports newest features in containerD (encrypted container images, lazy pulling...)
@@ -28,6 +42,21 @@ Earn IBM Fullstack developer certificate (but afte)
 	- `crictl pods` shows pods
 	- `crictl --runtime endpoint` enables you to specify a runtime endpoint (or use CONTAINER_RUNTIME_ENDPOINT env var)
 	- other commands are similar to docker
+
+Kubernetes definition file:
+```yml
+apiVersion: v1
+kind: Pod
+metadata:  //dictionary, can only have name and labels
+	name: myapp-pod
+	labels: // can have any sub-attributes
+		app: myapp
+spec:  //individual for all deployments
+  containers:
+    - name: nginx-container
+      image: nginx
+```
+
 ## Glossary
 - CRI: Container Runtime Interface
 	- Kubernetes originally only worked for Docker but then introduced the CRI to be more abstract and allow all sorts of container runtimes