What • Install • Build • Run • Resources
This repository stores a simple kubernetes setup to run the ROS robotic middleware on a distributed cluster. To our knowledge, most of the available tutorials and examples are either outdated or not well documented. Some of them are reported in the Resources section.
This setup is composed of three deployments, each of them running a single-container pod:
roscore-deploymentRuns the roscore processtalker-deploymentPublishes a string message to the/chattertopiclistener-deploymentSubscribes to the/chattertopic and echoes the string
The quicker way to run this kubernetes setup is creating a local cluster with tools such as minikube or kind. Since this is a very trivial setup, we'll be using kind which provides an easy and lightweight cluster. We assume that you already have docker, docker-compose, and kubectl installed, configured, and running in your machine.
Refer to the kind repository for the official installation instructions. We'll recap here below the steps we followed:
git clone --depth 1 https://github.com/kubernetes-sigs/kind
cd kind
make buildThen, either add the <path-to-cloned-kind-repo>/bin/ folder to your PATH or add alias kind='<path-to-cloned-kind-repo>/bin/kind' to your ~/.bashrc.
All the ROS pods will be running the official ros/melodic-ros-core image. To simplify the kubernetes and kind setup, we extended the official image with minor modifications. You can find the Dockerfiles in the docker folder.
Execute the following commands to build the ROS images:
cd docker
docker-compose -f build-ros-cluster.yml buildAfter this, make sure with docker images that the following images have been successfully built:
roscluster/master:v0roscluster/node:v0
The first step to run the setup is starting a local cluster. Execute:
kind create cluster
export KUBECONFIG="$(kind get kubeconfig-path)"Make sure executing docker ps -a that the kindest/node:v1.14.2 container is up and running. Also check that the cluster is running:
$ kubectl get all
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 1d17h
Then, load the docker images we built into the local cluster:
kind load docker-image roscluster/master:v0
kind load docker-image roscluster/node:v0The kubernetes setup is stored in the k8s folder. Execute the following to run the setup:
cd k8s
kubectl create -f .
The three deployments should now start. The talker and listener deployments will likely fail at the first attempt because they need to reach first roscore. Their deployment has an initContainer that tries to connect to roscore and restart the pod if it fails. Furthermore, if during their execution the roscore container fails or is restarted, a livenessProbe will restart the talker and listener containers.
Once that the cluster is running, you should have the following kubectl get all output:
NAME READY STATUS RESTARTS AGE
pod/listener-deployment-c7bfb7856-7lhz2 1/1 Running 1 37s
pod/roscore-deployment-7dd8db86d9-cxb7x 1/1 Running 0 37s
pod/talker-deployment-97cbb7744-b6gdr 1/1 Running 1 37s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d17h
service/service-listener ClusterIP None <none> 11311/TCP 37s
service/service-master ClusterIP None <none> 11311/TCP 37s
service/service-talker ClusterIP None <none> 11311/TCP 37s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/listener-deployment 1/1 1 1 37s
deployment.apps/roscore-deployment 1/1 1 1 37s
deployment.apps/talker-deployment 1/1 1 1 37s
NAME DESIRED CURRENT READY AGE
replicaset.apps/listener-deployment-c7bfb7856 1 1 1 37s
replicaset.apps/roscore-deployment-7dd8db86d9 1 1 1 37s
replicaset.apps/talker-deployment-97cbb7744 1 1 1 37s
You can get the listener log containing the topic message executing kubectl logs -l node=listener (note that the log is cut using label selectors, use the listener pod name for a complete log).