Add miscellaneous examples

examples/miscellaneous/README.md

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+# Miscellaneous Examples
+
+This example provides miscellaneous architecture diagrams for CronJob, LimitRange, NetworkPolicy, and ResourceQuota resource kinds.
+
+## Instructions
+
+Start a Kubernetes cluster.
+
+Generate some miscellaneous architecture diagrams:
+
+```sh
+$ ./generate.sh
+```
+
+## Generated architecture diagrams
+
+Architecture diagram for [cronjob.yaml](cronjob.yaml):
+![cronjob.png](cronjob.png)
+
+Architecture diagram for a deployed [cronjob.yaml](cronjob.yaml) instance:
+![cronjob-deployed.png](cronjob-deployed.png)
+
+Architecture diagram for [limit-ranges.yaml](limit-ranges.yaml):
+![limit-ranges.png](limit-ranges.png)
+
+Architecture diagram for [nginx.yaml](nginx.yaml):
+![nginx.png](nginx.png)
+
+Architecture diagram for a deployed [nginx.yaml](nginx.yaml) instance showing `Endpoints` resources:
+![nginx-deployed-only-ep.png](nginx-deployed-only-ep.png)
+
+Architecture diagram for a deployed [nginx.yaml](nginx.yaml) instance showing `EndpointSlice` resources:
+![nginx-deployed-only-eps.png](nginx-deployed-only-eps.png)
+
+Architecture diagram for a deployed [nginx.yaml](nginx.yaml) instance showing both `Endpoints` and `EndpointSlice` resources:
+![nginx-deployed-all.png](nginx-deployed-all.png)
+
+Architecture diagram for [network_policies.yaml](network_policies.yaml):
+![network_policies.png](network_policies.png)
+
+Architecture diagram for [quotas.yaml](quotas.yaml):
+![quotas.png](quotas.png)
+
+All-in-one architecture diagram:
+![all-in-one.png](all-in-one.png)

examples/miscellaneous/cronjob.yaml

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+# Source: https://k8s.io/examples/application/job/cronjob.yaml
+# https://kubernetes.io/docs/tasks/job/automated-tasks-with-cron-jobs/
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: hello
+spec:
+  schedule: "* * * * *"
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: hello
+            image: busybox:1.28
+            imagePullPolicy: IfNotPresent
+            command:
+            - /bin/sh
+            - -c
+            - date; echo Hello from the Kubernetes cluster
+          restartPolicy: OnFailure

examples/miscellaneous/generate.sh

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+#! /bin/sh
+
+PATH=../../bin:$PATH
+
+echo_run()
+{
+  echo $@
+  $@
+}
+
+if [ "$1" = "deployed" ]
+then
+  echo_run kubectl apply -f cronjob.yaml
+  echo_run sleep 150
+  echo kubectl get
+  kubectl get cronjob,job,pod,cm,sa,node -o=yaml > cronjob-deployed.yaml
+  echo_run kubectl delete cronjob hello
+
+  echo_run kubectl apply -f nginx.yaml
+  echo_run sleep 60
+  kubectl get all,ingress,ingressclass,networkpolicy,ep,endpointslice,cm,sa,node -o=yaml > nginx-deployed-all.yaml
+  kubectl get all,ingress,ingressclass,networkpolicy,ep,cm,sa,node -o=yaml > nginx-deployed-only-ep.yaml
+  kubectl get all,ingress,ingressclass,networkpolicy,endpointslice,cm,sa,node -o=yaml > nginx-deployed-only-eps.yaml
+  echo_run kubectl delete -f nginx.yaml
+fi
+
+# Generate the miscellaneous architecture diagrams.
+for file in `ls *.yaml`
+do
+  echo_run kube-diagrams -v $file
+done
+
+echo_run kube-diagrams -v -o all-in-one \
+  cronjob.yaml \
+  limit-ranges.yaml	\
+  network_policies.yaml \
+  nginx.yaml \
+  quotas.yaml

examples/miscellaneous/limit-ranges.yaml

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+# Source: https://kubernetes.io/docs/concepts/policy/limit-range/
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: cpu-resource-constraint
+spec:
+  limits:
+  - default: # this section defines default limits
+      cpu: 500m
+    defaultRequest: # this section defines default requests
+      cpu: 500m
+    max: # max and min define the limit range
+      cpu: "1"
+    min:
+      cpu: 100m
+    type: Container
+---
+# Source: https://k8s.io/examples/admin/resource/memory-constraints.yaml
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: mem-min-max-demo-lr
+spec:
+  limits:
+  - max:
+      memory: 1Gi
+    min:
+      memory: 500Mi
+    type: Container
+---
+# Source: https://kubernetes.io/docs/tasks/administer-cluster/limit-storage-consumption/
+apiVersion: v1
+kind: LimitRange
+metadata:
+  name: storagelimits
+spec:
+  limits:
+  - type: PersistentVolumeClaim
+    max:
+      storage: 2Gi
+    min:
+      storage: 1Gi

examples/miscellaneous/network_policies.yaml

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+# From https://github.com/NickSchleicher/k8d/blob/master/example/sample_policies.yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: myapp-pod
+  namespace: default
+  labels:
+    app: myapp-pod
+spec:
+  containers:
+  - name: nginx
+    image: nginx:1.7.9
+    ports:
+    - containerPort: 80
+
+---
+
+apiVersion: v1
+kind: Pod
+metadata:
+  name: myapp-pod2
+  namespace: default
+  labels:
+    app: myapp-pod2
+spec:
+  containers:
+  - name: myapp-container
+    image: byrnedo/alpine-curl
+    command: ["/bin/sh"]
+    args: ["-c", "sleep 36000"]
+
+---
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: myapp-pod
+  namespace: default
+  labels:
+    app: myapp-pod
+spec:
+  ports:
+  - port: 80
+    protocol: TCP
+  selector:
+    app: myapp-pod
+
+---
+
+kind: NetworkPolicy
+apiVersion: networking.k8s.io/v1
+metadata:
+  name: myapp-pod-to-myapp-pod2
+  namespace: default
+spec:
+  podSelector:
+    matchLabels:
+      app: myapp-pod
+  ingress:
+  - from:
+    - ipBlock:
+        cidr: 1.1.1.1/32
+    - ipBlock:
+        cidr: 2.2.2.2/32
+    - podSelector:
+        matchLabels:
+          app: myapp-pod2
+    ports:
+    - port: 80
+      protocol: UDP
+
+---
+
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny-ingress
+spec:
+  podSelector: {}
+  policyTypes:
+  - Ingress
+
+---
+
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-all-ingress
+spec:
+  podSelector: {}
+  ingress:
+  - {}
+  policyTypes:
+  - Ingress
+
+---
+
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny-egress
+spec:
+  podSelector: {}
+  policyTypes:
+  - Egress
+
+---
+
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-all-egress
+spec:
+  podSelector: {}
+  egress:
+  - {}
+  policyTypes:
+  - Egress
+
+# default deny ingress is overwritten by explicit allow ingress policies
+# default allow ingress overwrites specific deny (explicit)
+# default deny egress is overwritten by explicit allow egress policies
+# default allow egress overwrites specific deny egress (explicit)

examples/miscellaneous/nginx.yaml

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+# Inspired from https://k8s.io/examples/application/deployment.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+  labels:
+    app: nginx
+spec:
+  selector:
+    matchLabels:
+      app: nginx
+  replicas: 3 # tells deployment to run 3 pods matching the template
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.14.2
+        ports:
+        - containerPort: 80
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx-service
+  labels:
+    app: nginx
+spec:
+  selector:
+    app: nginx
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 80
+---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: nginx-ingress
+  annotations:
+    nginx.ingress.kubernetes.io/rewrite-target: /
+  labels:
+    app: nginx
+spec:
+  rules:
+  - http:
+      paths:
+      - path: /
+        pathType: Prefix
+        backend:
+          service:
+            name: nginx-service
+            port:
+              number: 80
+---
+# Inspired from https://kubernetes.io/docs/concepts/services-networking/network-policies/
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: nginx-network-policy
+  labels:
+    app: nginx
+spec:
+  podSelector:
+    matchLabels:
+      app: nginx
+  policyTypes:
+  - Ingress
+  - Egress
+  ingress:
+  - {}
+  egress:
+  - {}

examples/miscellaneous/quotas.yaml

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+# Source: https://kubernetes.io/docs/concepts/policy/resource-quotas/
+apiVersion: v1
+kind: List
+items:
+- apiVersion: v1
+  kind: ResourceQuota
+  metadata:
+    name: pods-high
+  spec:
+    hard:
+      cpu: "1000"
+      memory: 200Gi
+      pods: "10"
+    scopeSelector:
+      matchExpressions:
+      - operator : In
+        scopeName: PriorityClass
+        values: ["high"]
+- apiVersion: v1
+  kind: ResourceQuota
+  metadata:
+    name: pods-medium
+  spec:
+    hard:
+      cpu: "10"
+      memory: 20Gi
+      pods: "10"
+    scopeSelector:
+      matchExpressions:
+      - operator : In
+        scopeName: PriorityClass
+        values: ["medium"]
+- apiVersion: v1
+  kind: ResourceQuota
+  metadata:
+    name: pods-low
+  spec:
+    hard:
+      cpu: "5"
+      memory: 10Gi
+      pods: "10"
+    scopeSelector:
+      matchExpressions:
+      - operator : In
+        scopeName: PriorityClass
+        values: ["low"]