To test Gerrit on Kubernetes locally, a one-node cluster can be set up using Minikube. Minikube provides basic Kubernetes functionality and allows to quickly deploy and evaluate a Kubernetes deployment. This tutorial will guide through setting up Minikube to deploy the gerrit- master and gerrit-slave helm charts to it. Note, that due to limited compute resources on a single local machine and the restricted functionality of Minikube, the full functionality of the charts might not be usable.
To use Minikube, a hypervisor is needed. A good non-commercial solution is HyperKit. The Minikube project provides binaries to install the driver:
curl -LO https://storage.googleapis.com/minikube/releases/latest/docker-machine-driver-hyperkit \ && sudo install -o root -g wheel -m 4755 docker-machine-driver-hyperkit /usr/local/bin/
To manage Kubernetes clusters, the Kubectl CLI tool will be needed. A detailed guide how to do that for all supported OSs can be found here. On OSX hombrew can be used for installation:
brew install kubernetes-cli
Finally, Minikube can be installed. Download the latest binary here. To install it on OSX, run:
VERSION=1.1.0 curl -Lo minikube https://storage.googleapis.com/minikube/releases/v$VERSION/minikube-darwin-amd64 && \ chmod +x minikube && \ sudo cp minikube /usr/local/bin/ && \ rm minikube
For a more detailed overview over the features of Minikube refer to the official documentation. If a hypervisor driver other than virtual box (e.g. hyperkit) is used, set the --vm-driver option accordingly:
minikube config set vm-driver hyperkit
The gerrit-master and gerrit-slave charts are configured to work with the default resource limits configured for minikube (2 cpus and 2Gi RAM). If more resources are desired (e.g. to speed up deployment startup or for more resource intensive tests), configure the resource limits using:
minikube config set memory 4096 minikube config set cpus 4
To install a full Gerrit master and Gerrit slave setup with reasonable startup times, Minikube will need about 9.5 GB of RAM and 3-4 CPUs! But the more the better.
To start a Minikube cluster simply run:
minikube start
Starting up the cluster will take a while. The installation should automatically configure kubectl to connect to the Minikube cluster. Run the following command to test whether the cluster is up:
kubectl get nodes NAME STATUS ROLES AGE VERSION minikube Ready master 1h v1.14.2
The helm-charts use ingresses, which can be used in Minikube by enabling the ingress addon:
minikube addons enable ingress
Since for testing there will probably no usable host names configured to point to the minikube installation, the traffic to the hostnames configured in the Ingress definition needs to be redirected to Minikube by editing the /etc/hosts- file, adding a line containing the Minikube IP and a whitespace-delimited list of all the hostnames:
echo "$(minikube ip) master.gerrit backend.gerrit slave.gerrit" | sudo tee -a /etc/hosts
The host names (e.g. master.gerrit) are the defaults, when using the values.yaml files provided as and example for minikube. Change them accordingly, if a different one is chosen. This will only redirect traffic from the computer running Minikube.
To see whether all cluster components are ready, run:
kubectl get pods --all-namespaces
The status of all components should be Ready. The kubernetes dashboard giving an overview over all cluster components, can be opened by executing:
minikube dashboard
Helm is needed to install and manage the helm charts. To install the helm client on your local machine (running OSX), run:
brew install kubernetes-helm
A guide for all suported OSs can be found here.
For helm being able to install charts on a Kubernetes cluster, it needs Tiller installed. To do that, run:
helm init
The helm-charts need a volume with ReadWriteMany access mode to store git-repositories. This guide will use the nfs-server-provisioner chart to provide NFS-volumes directly in the cluster. A basic configuration file for the nfs-server- provisioner-chart is provided in the supplements-directory. It can be installed by running:
helm install stable/nfs-server-provisioner \ --name nfs \ -f ./supplements/nfs.minikube.values.yaml
A configuration file to configure the gerrit-master chart is provided at ./supplements/gerrit-master.minikube.values.yaml. To install the gerrit-master chart on Minikube, run:
helm install ./helm-charts/gerrit-master \ -f ./supplements/gerrit-master.minikube.values.yaml \ --dep-up \ -n gerrit-master
Startup may take some time, especially when allowing only a small amount of resources to the containers. Check progress with kubectl get pods -w until it says that the pod gerrit-master-gerrit-master-stateful-set-0 is Running. Then use kubectl logs -f gerrit-master-gerrit-master-stateful-set-0 to follow the startup process of Gerrit until a line like this shows that Gerrit is ready:
[2019-06-04 15:24:25,914] [main] INFO com.google.gerrit.pgm.Daemon : Gerrit Code Review 2.16.8-86-ga831ebe687 ready
To open Gerrit's UI, run:
open http://master.gerrit
A custom configuration file to configure the gerrit-slave chart is provided at ./supplements/gerrit-slave.minikube.values.yaml. Install it by running:
helm install ./helm-charts/gerrit-slave \ -f ./supplements/gerrit-slave.minikube.values.yaml \ --dep-up \ -n gerrit-slave
The slave will start up, which can be followed by running:
kubectl logs -f gerrit-slave-gerrit-slave-deployment-<id>
Replication of repositories has to be started on the Gerrit master, e.g. by making a change in the respective repositories. Only then previous changes to the repositories will be available on the slave.
Shut down minikube:
minikube stop
Delete the minikube cluster:
minikube delete
Remove the line added to /etc/hosts. If Minikube is restarted, the cluster will get a new IP and the /etc/hosts-entry has to be adjusted.