Kubernetes add DaemonSet for direct cameras

docs/service.kubernetes.md

@@ -25,12 +25,22 @@ for the content you can use with a [kustomize](https://kustomize.io/).
 
 - [deployment-1.yaml](https://github.com/nvtkaszpir/prusa-connect-camera-script/blob/master/k8s/deployment-1.yaml)
   is an example to fetch image from a stream using ffmpeg and with custom
-  prusa-connect-camera.sh for easier development/iteration
+  prusa-connect-camera.sh for easier development/iteration.
+  This is also preferred option when you are not using cameras that are directly
+  attached to the hosts, but rely on using ffmpeg to fetch images from remote
+  streams or static images via curl.
 
 - [deployment-2.yaml](https://github.com/nvtkaszpir/prusa-connect-camera-script/blob/master/k8s/deployment-2.yaml)
   is an example how to run it on Raspberry Pi with USB camera using default parameters.
   You want to change `.spec.nodeName` and volumes to point to desired camera.
 
+- [daemonset.yaml](https://github.com/nvtkaszpir/prusa-connect-camera-script/blob/master/k8s/daemonset.yaml)
+  is an example how to run it on Raspberry Pi with USB camera using default parameters.
+  You want to change `.spec.nodeName` and volumes to point to desired camera.
+  The difference between the DaemonSet and Deployment is that with the Deployment
+  kubernetes will try to spawn new pods even if node is not available.
+  DaemonSet it is better when you have to use directly attached devices to the hosts.
+
 ## More copies
 
 If you want to add more cameras then you should:

k8s/daemonset.yaml

@@ -0,0 +1,89 @@
+---
+apiVersion: apps/v1
+kind: DaemonSet
+
+metadata:
+  name: cam-2
+  labels:
+    app.kubernetes.io/name: cam-2
+spec:
+  revisionHistoryLimit: 3
+
+  updateStrategy:
+    type: RollingUpdate
+
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: cam-2
+
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: cam-2
+
+    spec:
+      nodeName: hormex # change this to the desired host with given hardware
+      automountServiceAccountToken: false
+      enableServiceLinks: false
+      containers:
+        - name: prusa-connect-script
+          tty: true # get that logs flowing to stdout/stderr
+          envFrom:
+            - secretRef:
+                name: cam-2
+          image: quay.io/kaszpir/prusa-connect-script:latest
+          imagePullPolicy: IfNotPresent
+          lifecycle:
+            preStop:
+              exec:
+                command: ["/bin/sh","-c","echo graceful-shutdown-start;sleep 2;echo graceful-shutdown-end"] # wait for inflight requests to finish
+          livenessProbe:
+            exec:
+              command:
+                - bash
+                - -c
+                - test $(find /dev/shm/ -mmin -1 | wc -l) -gt "0"
+            initialDelaySeconds: 5
+            periodSeconds: 15
+
+          securityContext:
+            # allowPrivilegeEscalation: false
+            privileged: true
+            readOnlyRootFilesystem: true
+            runAsNonRoot: true
+            runAsUser: 1000
+            capabilities:
+              drop:
+                - ALL
+              # add:
+              #   - NET_RAW # needed for ping if not using
+
+          resources:
+            requests:
+              cpu: "0.1"
+              memory: "32Mi"
+            limits:
+              cpu: "1.0"
+              memory: "128Mi"
+
+          volumeMounts:
+            - mountPath: /dev/shm
+              name: dev-shm
+            - mountPath: /dev/video999 # must be the same as in `volumes` section and in cam.env
+              name: dev-video
+      # securityContext:
+      #   runAsUser: 1000
+      #   # runAsGroup: video
+      #   # fsGroup: 2000
+      tolerations:
+        - key: "rpi"
+          operator: "Exists"
+          effect: "NoSchedule"
+      terminationGracePeriodSeconds: 5
+      volumes:
+        - name: dev-shm
+          emptyDir:
+            medium: Memory
+        - name: dev-video
+          hostPath:
+            path: /dev/video1 # change this to the device on the host

k8s/kustomization.yaml

@@ -8,6 +8,7 @@ resources:
 
   - deployment-1.yaml
   # - deployment-2.yaml
+  - daemonset.yaml
 
 secretGenerator:
   - name: cam-1