init commit

ClusterSetup.txt

+Commands to initialize cluster (pay attention to sudo useage):
+
+sudo kubeadm init --pod-network-cidr=10.244.0.0/16
+
+or, if using config file
+
+sudo kubeadm init --config kubeadm-config.yaml
+
+In either case, may need to turn off swap memory to get cluster up:
+
+sudo swapoff -a
+
+...
+
+after thats done do, somehow the mkdir and chown need to be run every time:
+
+mkdir -p $HOME/.kube
+sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
+sudo chown $(id -u):$(id -g) $HOME/.kube/config
+
+start up cluster networking with one of the following:
+
+requires internet:
+kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
+
+requires the kube-flannel.yml file locally:
+kubectl apply -f kube-flannel.yml
+
+check that pods/nodes are up, can take a while due to launch order:
+
+kubectl get pods --all-namespaces
+
+allow pods to run on control-plane node (by removing the taint on all nodes):
+
+kubectl taint nodes --all node-role.kubernetes.io/master-
+
+-----------------------------------------------------
+
+ros_on_kubernetes set up steps:
+
+kubectl create -f ros_on_kubernetes
+
+kubectl get all
+
+kubectl exec -it listener bash (deprech kubectl exec -it listener -- bash)
+
+source .. yadda ya bumdadada
+
+-----------------------------------------------------
+
+turning off nodes:
+
+first drain node (kubectl get nodes, for node name):
+
+kubectl drain <node name> --delete-emptydir-data --force --ignore-daemonsets
+
+reset cluster:
+
+sudo kubeadm reset
+
+reset ipv6 tables and such (seems to work fine without but eh):
+
+iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X
+
+another ipvs reset:
+
+ipvsadm -C
+
+now you can finally delete the node(s) in question:
+
+kubectl delete node <node name>
+
+--------------------------------------------------------
+
+handy interaction commands
+
+get into pod bash shell (remove -it and just put command for noninteractive):
+
+kubectl exec <pod_name> -it -- bash

dockerComposeTesting/Dockerfile

+# syntax=docker/dockerfile:1
+FROM python:3.7-alpine
+WORKDIR /code
+ENV FLASK_APP=app.py
+ENV FLASK_RUN_HOST=0.0.0.0
+RUN apk add --no-cache gcc musl-dev linux-headers
+COPY requirements.txt requirements.txt
+RUN pip install -r requirements.txt
+EXPOSE 5000
+COPY . .
+CMD ["flask", "run"]

dockerComposeTesting/app.py

+import time
+
+import redis
+from flask import Flask
+
+app = Flask(__name__)
+cache = redis.Redis(host='redis', port=6379)
+
+def get_hit_count():
+	retries = 5
+	while True:
+		try:
+			return cache.incr('hits')
+		except redis.exceptions.ConnectionError as exc:
+			if retries == 0:
+				raise exc
+			retries -= 1
+			time.sleep(0.5)
+
+@app.route('/')
+def hello():
+	count = get_hit_count()
+	return 'Hello World! I have been seen {} times.\n'.format(count)

dockerComposeTesting/docker-compose.yml

+version: "3.3"
+services:
+  web:
+    build: .
+    ports:
+      - "5000:5000"
+  redis:
+    image: "redis:alpine"

dockerComposeTesting/requirements.txt

+flask
+redis

dockerComposeTesting/steps.txt

+To test a quick docker web app, with steps/code taken from https://docs.docker.com/compose/gettingstarted/
+
+- from project directory, start up docker daemon (not sure why this isn't a service):
+
+sudo dockerd
+
+- bring up container (again from project dir, separate terminal):
+
+sudo docker-compose up
+
+- check http://localhost:5000/ to see if page loads, refresh to see counter incrementing
+
+if dockerd comes back with an error the following command might be needed:
+ps axf | grep docker | grep -v grep | awk '{print "kill -9 " $1}' | sudo sh

dockerSaveTesting/Dockerfile

+FROM busybox
+CMD echo $((40 + 2))

dockerSaveTesting/calc/42ca20c5edcca8f3790773dd6111e6eb360f56a7a2fabcd4feba72a940b1eccb.json

+{"architecture":"amd64","config":{"Hostname":"","Domainname":"","User":"","AttachStdin":false,"AttachStdout":false,"AttachStderr":false,"Tty":false,"OpenStdin":false,"StdinOnce":false,"Env":["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"],"Cmd":["/bin/sh","-c","echo $((40 + 2))"],"Image":"sha256:42b97d3c2ae95232263a04324aaf656dc80e7792dee6629a9eff276cdfb806c0","Volumes":null,"WorkingDir":"","Entrypoint":null,"OnBuild":null,"Labels":null},"container":"7844ba4fcb3e2573beee308f75094be8428cf1a99076340d971f9f0b2b61b9cc","container_config":{"Hostname":"7844ba4fcb3e","Domainname":"","User":"","AttachStdin":false,"AttachStdout":false,"AttachStderr":false,"Tty":false,"OpenStdin":false,"StdinOnce":false,"Env":["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"],"Cmd":["/bin/sh","-c","#(nop) ","CMD [\"/bin/sh\" \"-c\" \"echo $((40 + 2))\"]"],"Image":"sha256:42b97d3c2ae95232263a04324aaf656dc80e7792dee6629a9eff276cdfb806c0","Volumes":null,"WorkingDir":"","Entrypoint":null,"OnBuild":null,"Labels":{}},"created":"2021-09-13T17:33:29.768365573Z","docker_version":"20.10.8","history":[{"created":"2021-08-20T21:20:01.375838656Z","created_by":"/bin/sh -c #(nop) ADD file:89552401a4d4fc6b2e7e019e9dff35d16de40ad30973d5ccdd78d3de33790155 in / "},{"created":"2021-08-20T21:20:01.541762445Z","created_by":"/bin/sh -c #(nop)  CMD [\"sh\"]","empty_layer":true},{"created":"2021-09-13T17:33:29.768365573Z","created_by":"/bin/sh -c #(nop)  CMD [\"/bin/sh\" \"-c\" \"echo $((40 + 2))\"]","empty_layer":true}],"os":"linux","rootfs":{"type":"layers","diff_ids":["sha256:0fd05bf2930d72edc1aa0b9fa7e442295c2384512a32c0b1502392f5384acd81"]}}
\ No newline at end of file

dockerSaveTesting/calc/e93c093b65bb10672e77027c11ee804f192a401d94cf1b8f53fcc84d6335f6d3/VERSION

+1.0
\ No newline at end of file

dockerSaveTesting/calc/e93c093b65bb10672e77027c11ee804f192a401d94cf1b8f53fcc84d6335f6d3/json

+{"id":"e93c093b65bb10672e77027c11ee804f192a401d94cf1b8f53fcc84d6335f6d3","created":"2021-09-13T17:33:29.768365573Z","container":"7844ba4fcb3e2573beee308f75094be8428cf1a99076340d971f9f0b2b61b9cc","container_config":{"Hostname":"7844ba4fcb3e","Domainname":"","User":"","AttachStdin":false,"AttachStdout":false,"AttachStderr":false,"Tty":false,"OpenStdin":false,"StdinOnce":false,"Env":["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"],"Cmd":["/bin/sh","-c","#(nop) ","CMD [\"/bin/sh\" \"-c\" \"echo $((40 + 2))\"]"],"Image":"sha256:42b97d3c2ae95232263a04324aaf656dc80e7792dee6629a9eff276cdfb806c0","Volumes":null,"WorkingDir":"","Entrypoint":null,"OnBuild":null,"Labels":{}},"docker_version":"20.10.8","config":{"Hostname":"","Domainname":"","User":"","AttachStdin":false,"AttachStdout":false,"AttachStderr":false,"Tty":false,"OpenStdin":false,"StdinOnce":false,"Env":["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"],"Cmd":["/bin/sh","-c","echo $((40 + 2))"],"Image":"sha256:42b97d3c2ae95232263a04324aaf656dc80e7792dee6629a9eff276cdfb806c0","Volumes":null,"WorkingDir":"","Entrypoint":null,"OnBuild":null,"Labels":null},"architecture":"amd64","os":"linux"}
\ No newline at end of file

dockerSaveTesting/calc/manifest.json

+[{"Config":"42ca20c5edcca8f3790773dd6111e6eb360f56a7a2fabcd4feba72a940b1eccb.json","RepoTags":["calc:latest"],"Layers":["e93c093b65bb10672e77027c11ee804f192a401d94cf1b8f53fcc84d6335f6d3/layer.tar"]}]

dockerSaveTesting/calc/repositories

+{"calc":{"latest":"e93c093b65bb10672e77027c11ee804f192a401d94cf1b8f53fcc84d6335f6d3"}}

dockerSaveTesting/dockerSaveSteps.txt

+How to do basic saving and loading of containers/images, steps taken from https://pspdfkit.com/blog/2019/docker-import-export-vs-load-save/
+
+- start up docker daemon in separate terminal in project dir:
+
+sudo dockerd
+
+- assuming we already have a Dockerfile, build image using tag "calc" of current directory
+
+sudo docker build --tag calc .
+
+- check that docker actually built the image and stored it locally
+
+sudo docker images OR sudo docker image ls
+
+- run image tagged "calc" and see test output
+
+sudo docker run calc
+
+- save the image in question to a tar file in the current directory
+
+sudo docker save calc > calc.tar
+
+- check out the contents of the image after saving
+
+mkdir calc && tar -xf calc.tar -C calc THEN tree calc
+
+- delete the local image (if for some reason you want to rebuild/import it):
+
+(get all containers)
+sudo docker ps -a
+(remove a specific container so we can delete the image later)
+sudo docker rm <container_id>
+(then delete the image via tag or id)
+sudo docker image ls
+sudo docker image rm <tag/id>
+
+- also can delete all exited containers via this kickass command:
+
+sudo docker ps -a | grep Exit | cut -d ' ' -f 1 | xargs sudo docker rm
+
+- load image from tar file
+
+sudo docker load < calc.tar
+
+- run it again to confirm it works (can also look and make sure image is there)
+
+sudo docker run calc

flannel.yml

+---
+apiVersion: policy/v1beta1
+kind: PodSecurityPolicy
+metadata:
+  name: psp.flannel.unprivileged
+  annotations:
+    seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
+    seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
+    apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
+    apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
+spec:
+  privileged: false
+  volumes:
+  - configMap
+  - secret
+  - emptyDir
+  - hostPath
+  allowedHostPaths:
+  - pathPrefix: "/etc/cni/net.d"
+  - pathPrefix: "/etc/kube-flannel"
+  - pathPrefix: "/run/flannel"
+  readOnlyRootFilesystem: false
+  # Users and groups
+  runAsUser:
+    rule: RunAsAny
+  supplementalGroups:
+    rule: RunAsAny
+  fsGroup:
+    rule: RunAsAny
+  # Privilege Escalation
+  allowPrivilegeEscalation: false
+  defaultAllowPrivilegeEscalation: false
+  # Capabilities
+  allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
+  defaultAddCapabilities: []
+  requiredDropCapabilities: []
+  # Host namespaces
+  hostPID: false
+  hostIPC: false
+  hostNetwork: true
+  hostPorts:
+  - min: 0
+    max: 65535
+  # SELinux
+  seLinux:
+    # SELinux is unused in CaaSP
+    rule: 'RunAsAny'
+---
+kind: ClusterRole
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: flannel
+rules:
+- apiGroups: ['extensions']
+  resources: ['podsecuritypolicies']
+  verbs: ['use']
+  resourceNames: ['psp.flannel.unprivileged']
+- apiGroups:
+  - ""
+  resources:
+  - pods
+  verbs:
+  - get
+- apiGroups:
+  - ""
+  resources:
+  - nodes
+  verbs:
+  - list
+  - watch
+- apiGroups:
+  - ""
+  resources:
+  - nodes/status
+  verbs:
+  - patch
+---
+kind: ClusterRoleBinding
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: flannel
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: flannel
+subjects:
+- kind: ServiceAccount
+  name: flannel
+  namespace: kube-system
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: flannel
+  namespace: kube-system
+---
+kind: ConfigMap
+apiVersion: v1
+metadata:
+  name: kube-flannel-cfg
+  namespace: kube-system
+  labels:
+    tier: node
+    app: flannel
+data:
+  cni-conf.json: |
+    {
+      "name": "cbr0",
+      "cniVersion": "0.3.1",
+      "plugins": [
+        {
+          "type": "flannel",
+          "delegate": {
+            "hairpinMode": true,
+            "isDefaultGateway": true
+          }
+        },
+        {
+          "type": "portmap",
+          "capabilities": {
+            "portMappings": true
+          }
+        }
+      ]
+    }
+  net-conf.json: |
+    {
+      "Network": "10.244.0.0/16",
+      "Backend": {
+        "Type": "vxlan"
+      }
+    }
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: kube-flannel-ds
+  namespace: kube-system
+  labels:
+    tier: node
+    app: flannel
+spec:
+  selector:
+    matchLabels:
+      app: flannel
+  template:
+    metadata:
+      labels:
+        tier: node
+        app: flannel
+    spec:
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+            - matchExpressions:
+              - key: kubernetes.io/os
+                operator: In
+                values:
+                - linux
+      hostNetwork: true
+      priorityClassName: system-node-critical
+      tolerations:
+      - operator: Exists
+        effect: NoSchedule
+      serviceAccountName: flannel
+      initContainers:
+      - name: install-cni
+        image: quay.io/coreos/flannel:v0.14.0
+        command:
+        - cp
+        args:
+        - -f
+        - /etc/kube-flannel/cni-conf.json
+        - /etc/cni/net.d/10-flannel.conflist
+        volumeMounts:
+        - name: cni
+          mountPath: /etc/cni/net.d
+        - name: flannel-cfg
+          mountPath: /etc/kube-flannel/
+      containers:
+      - name: kube-flannel
+        image: quay.io/coreos/flannel:v0.14.0
+        command:
+        - /opt/bin/flanneld
+        args:
+        - --ip-masq
+        - --kube-subnet-mgr
+        resources:
+          requests:
+            cpu: "100m"
+            memory: "50Mi"
+          limits:
+            cpu: "100m"
+            memory: "50Mi"
+        securityContext:
+          privileged: false
+          capabilities:
+            add: ["NET_ADMIN", "NET_RAW"]
+        env:
+        - name: POD_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
+        - name: POD_NAMESPACE
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.namespace
+        volumeMounts:
+        - name: run
+          mountPath: /run/flannel
+        - name: flannel-cfg
+          mountPath: /etc/kube-flannel/
+      volumes:
+      - name: run
+        hostPath:
+          path: /run/flannel
+      - name: cni
+        hostPath:
+          path: /etc/cni/net.d
+      - name: flannel-cfg
+        configMap:
+          name: kube-flannel-cfg

kubeadm-config.yaml

+# kubeadm-config.yaml
+kind: ClusterConfiguration
+apiVersion: kubeadm.k8s.io/v1beta2
+kubernetesVersion: v1.21.3
+networking:
+  podSubnet: "10.244.0.0/16"
+---
+kind: KubeletConfiguration
+apiVersion: kubelet.config.k8s.io/v1beta1
+cgroupDriver: systemd

llhApproach/docker/buildRosCluster.yml

+version: '2.4'
+
+services:
+    master:
+        image: llhcluster/master:v0
+        build:
+            context: ./master/
+            args:
+                from: ros:noetic
+    node:
+        image: llhcluster/node:v0
+        build:
+            context: ./node/
+            args:
+                from: ros:noetic

llhApproach/docker/master/Dockerfile

+ARG from=ros:noetic
+FROM ${from}
+# install build tools
+# RUN apt-get update && apt-get install -y \
+#     python-catkin-tools \
+#     && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y python3-pip git
+# work around as the apt-get version fails
+RUN pip3 install git+https://github.com/catkin/catkin_tools.git
+
+# clone ros package repo
+ENV ROS_WS /opt/ros_ws
+RUN mkdir -p $ROS_WS/src
+WORKDIR $ROS_WS
+RUN git -C src clone \
+      -b $ROS_DISTRO-devel \
+      https://github.com/ros/ros_tutorials.git
+
+# install ros package dependencies
+RUN apt-get update && rosdep update && rosdep install -y --from-paths src/ros_tutorials/roscpp_tutorials --ignore-src
+
+# build ros package source
+RUN catkin config \
+      --extend /opt/ros/$ROS_DISTRO && \
+    catkin build \
+      roscpp_tutorials
+
+COPY ros_entrypoint.sh /usr/local/bin/ros_entrypoint.sh
+RUN chmod 755 /usr/local/bin/ros_entrypoint.sh
+
+ENTRYPOINT ["/usr/local/bin/ros_entrypoint.sh"]
+CMD ["roscore"]
+
+
+# source ros package from entrypoint
+# RUN sed --in-place --expression \
+#       '$isource "$ROS_WS/devel/setup.bash"' \
+#       /ros_entrypoint.sh
+
+# run ros package launch file
+# CMD ["roslaunch", "roscpp_tutorials", "talker_listener.launch"]

llhApproach/docker/master/ros_entrypoint.sh

+#!/bin/bash
+set -e
+
+echo "==> Executing master image entrypoint ..."
+
+# setup ros environment
+source "/opt/ros/$ROS_DISTRO/setup.bash"
+# might need to source the devel space as well
+source "$ROS_WS/devel/setup.bash"
+
+echo "==> Container ready"
+exec "$@"

llhApproach/docker/node/Dockerfile

+ARG from=ros:noetic
+FROM ${from}
+# install build tools
+# RUN apt-get update && apt-get install -y \
+#     python-catkin-tools \
+#     && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y python3-pip git
+RUN pip3 install git+https://github.com/catkin/catkin_tools.git
+
+# clone ros package repo
+ENV ROS_WS /opt/ros_ws
+RUN mkdir -p $ROS_WS/src
+WORKDIR $ROS_WS
+RUN git -C src clone \
+      -b $ROS_DISTRO-devel \
+      https://github.com/ros/ros_tutorials.git
+
+# install ros package dependencies
+RUN apt-get update && \
+    rosdep update && \
+    rosdep install -y \
+      --from-paths \
+        src/ros_tutorials/roscpp_tutorials \
+      --ignore-src && \
+    rm -rf /var/lib/apt/lists/*
+
+# build ros package source
+RUN catkin config \
+      --extend /opt/ros/$ROS_DISTRO && \
+    catkin build \
+      roscpp_tutorials
+
+COPY check_roscore.py /usr/local/bin/check_roscore.py
+COPY ros_entrypoint.sh /usr/local/bin/ros_entrypoint.sh
+
+RUN chmod 755 /usr/local/bin/check_roscore.py &&\
+    chmod 755 /usr/local/bin/ros_entrypoint.sh
+
+ENTRYPOINT ["/usr/local/bin/ros_entrypoint.sh"]
+CMD ["bash"]
+
+# run ros package launch file
+# CMD ["roslaunch", "roscpp_tutorials", "talker_listener.launch"]

llhApproach/docker/node/check_roscore.py

+#!/usr/bin/env python3
+
+import sys
+import rosgraph
+
+if not rosgraph.is_master_online():
+    print("Waiting roscore ...")
+    sys.exit(1)
+
+print("roscore found!")

llhApproach/docker/node/ros_entrypoint.sh

+#!/bin/bash
+set -e
+
+echo "==> Executing node image entrypoint ..."
+# setup ros environment
+source "/opt/ros/$ROS_DISTRO/setup.bash"
+# might need to source the devel space as well
+source "$ROS_WS/devel/setup.bash"
+
+echo "==> Container ready"
+exec "$@"

llhApproach/kubernetes/listener-deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: listener-deployment
+  labels:
+    app: llhcluster
+    node: listener
+spec:
+  replicas: 1
+  # The deployment handles all matching templated pods
+  selector:
+    matchLabels:
+      node: listener
+  # Template for a replica.
+  # The deployment makes sure that a POD containing the containers
+  # defined below is always running.
+  template:
+    metadata:
+      labels:
+        node: listener
+    spec:
+      # Wait roscore to be running before starting the pod.
+      # An initContainer is executed when this pod is created
+      # and tries to connect to the rocore which is running in
+      # a container in the master pod deployment.
+      # https://kubernetes.io/docs/concepts/workloads/pods/init-containers/
+      initContainers:
+      - name: init-service-listener
+        image: llhcluster/node:v0
+        args:
+        - check_roscore.py
+        env:
+        - name: ROS_MASTER_URI
+          value: http://service-master:11311
+        - name: ROS_HOSTNAME
+          value: service-listener
+      containers:
+      # The real node container
+      - name: llhclusterpublisher
+        image: llhcluster/node:v0
+        args:
+        - rostopic
+        - echo
+        - chatter
+        env:
+        - name: ROS_MASTER_URI
+          value: http://service-master:11311
+        - name: ROS_HOSTNAME
+          value: service-listener
+        # When the roscore container stops or fails, all the node
+        # containers need to be restarted because the ros network
+        # configuration is lost.
+        # This liveness probe restarts the node container if the
+        # 'chatter' topic is not anymore listed in the ROS network.
+        # This is required because the node doesn't fail automatically
+        # when roscore stops / restarts.
+        # https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-probes/
+        livenessProbe:
+          exec:
+            command:
+            - entrypoint.sh
+            - /opt/ros/melodic/bin/rostopic
+            - info
+            - chatter
+          initialDelaySeconds: 5
+          periodSeconds: 1
+
+---
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-listener
+  labels:
+    app: llhcluster
+    node: listener
+spec:
+  # Start a headless service
+  # https://kubernetes.io/docs/concepts/services-networking/service/#headless-services
+  clusterIP: None
+  ports:
+    # Dummy port
+    - port: 11311
+  selector:
+    node: listener

llhApproach/kubernetes/master-deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: roscore-deployment
+  labels:
+    app: llhcluster
+    node: roscore
+spec:
+  replicas: 1
+  # The deployment handles all matching templated pods
+  selector:
+    matchLabels:
+      node: roscore
+  # Template for a replica.
+  # The deployment makes sure that a POD containing the containers
+  # defined below is always running.
+  template:
+    metadata:
+      labels:
+        node: roscore
+    spec:
+      containers:
+      - name: llhclustermaster
+        image: llhcluster/master:v0
+        args:
+        - roscore
+        ports:
+        - containerPort: 11311
+          name: roscoreport
+
+---
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-master
+  labels:
+    app: llhcluster
+    node: roscore
+spec:
+  clusterIP: None
+  ports:
+    - port: 11311
+  selector:
+    node: roscore

llhApproach/kubernetes/talker-deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: talker-deployment
+  labels:
+    app: llhcluster
+    node: talker
+spec:
+  replicas: 1
+  # The deployment handles all matching templated pods
+  selector:
+    matchLabels:
+      node: talker
+  # Template for a replica.
+  # The deployment makes sure that a POD containing the containers
+  # defined below is always running.
+  template:
+    metadata:
+      labels:
+        node: talker
+    spec:
+      # Wait roscore to be running before starting the pod.
+      # An initContainer is executed when this pod is created
+      # and tries to connect to the rocore which is running in
+      # a container in the master pod deployment.
+      # https://kubernetes.io/docs/concepts/workloads/pods/init-containers/
+      initContainers:
+      - name: init-service-talker
+        image: llhcluster/node:v0
+        args:
+        - check_roscore.py
+        env:
+        - name: ROS_MASTER_URI
+          value: http://service-master:11311
+        - name: ROS_HOSTNAME
+          value: service-talker
+      containers:
+      # The real node container
+      - name: llhclusterpublisher
+        image: llhcluster/node:v0
+        args:
+        - "rostopic"
+        - "pub"
+        - "-r 1"
+        - "chatter"
+        - "std_msgs/String"
+        - "Hello, world"
+        env:
+        - name: ROS_MASTER_URI
+          value: http://service-master:11311
+        - name: ROS_HOSTNAME
+          value: service-talker
+        # When the roscore container stops or fails, all the node
+        # containers need to be restarted because the ros network
+        # configuration is lost.
+        # This liveness probe restarts the node container if the
+        # 'chatter' topic is not anymore listed in the ROS network.
+        # This is required because the node doesn't fail automatically
+        # when roscore stops / restarts.
+        # https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-probes/
+        livenessProbe:
+          exec:
+            command:
+            - entrypoint.sh
+            - /opt/ros/melodic/bin/rostopic
+            - info
+            - chatter
+          initialDelaySeconds: 5
+          periodSeconds: 1
+
+---
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-talker
+  labels:
+    app: llhcluster
+    node: talker
+spec:
+  # Start a headless service
+  # https://kubernetes.io/docs/concepts/services-networking/service/#headless-services
+  clusterIP: None
+  ports:
+    # Dummy port
+    - port: 11311
+  selector:
+    node: talker

podSpecs/listener_pod.yml

+apiVersion: v1
+kind: Pod
+metadata:
+  name: listener
+  labels:
+    name: listener
+spec:
+  containers: 
+   -  name: listener
+      image: ros:indigo-ros-core
+      env:
+        - name: ROS_HOSTNAME
+          value: listener
+        - name: ROS_MASTER_URI
+          value: http://master:11311
+      args:
+        - rostopic 
+        - echo 
+        - my_topic
+

podSpecs/listener_svc.yml

+apiVersion: v1
+kind: Service
+metadata: 
+  name: listener
+spec:
+  clusterIP: None
+  ports: 
+    - port: 11311
+      protocol: TCP
+  selector: 
+    name: listener
+  type: ClusterIP

podSpecs/master_pod.yml

+apiVersion: v1
+kind: Pod
+metadata:
+  name: master
+  labels:
+    name: master
+spec:
+  containers:
+   -  name: master
+      image: roscluster/master:v0
+      ports:
+        - containerPort: 11311
+          name: master
+      # args:
+      #     - roscore

podSpecs/master_svc.yml

+apiVersion: v1
+kind: Service
+metadata: 
+  name: master
+spec: 
+  clusterIP: None
+  ports: 
+    - port: 11311
+      protocol: TCP
+  selector: 
+    name: master
+  type: ClusterIP

podSpecs/talker_pod.yml

+apiVersion: v1
+kind: Pod
+metadata:
+  name: talker
+  labels:
+    name: talker
+spec:
+  containers: 
+   -  name: talker
+      image: ros:indigo-ros-core
+      env:
+        - name: ROS_HOSTNAME
+          value: talker
+        - name: ROS_MASTER_URI
+          value: http://master:11311
+      args:
+          - rostopic 
+          - pub 
+          - "-r"
+          - "1" 
+          - my_topic
+          - std_msgs/String
+          - "SPLab+ICClab"

podSpecs/talker_svc.yml

+apiVersion: v1
+kind: Service
+metadata: 
+  name: talker
+spec:
+  clusterIP: None
+  ports: 
+    - port: 11311
+      protocol: TCP
+  selector: 
+    name: talker
+  type: ClusterIP

ros-kubernetes-ex @ 316101e9

+Subproject commit 316101e906c06ce40993a4398a90ea2ba46b8000