Building your environment for testing or automation purposes can be difficult when using different technologies. In this guide you’ll find how to set up your system step-by-step to work with the latest versions of Kubernetes (up to today), CRI-O and KubeVirt.
In this series of blogposts the following topics are going to be covered en each post:
- Requirements: dependencies and containers runtime
- Kubernetes: Cluster and Network
- KubeVirt: requirements and first Virtual Machine
In the first blogpost of the series (KubeVirt on Kubernetes with CRI-O from scratch) the initial set up for a CRI-O runtime environment has been covered. In this post is shown the installation and configuration of Kubernetes based in the previous CRI-O environment.
If the ansible way was chosen, you may want to skip this section since the repository and needed packages were already installed during execution.
To install the K8s packages a new repo has to be added:
k8s-test.local# vim /etc/yum.repos.d/kubernetes.repo [Kubernetes] name=Kubernetes baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=1 repo_gpgcheck=1 gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
Now, the gpg keys of the packages can be imported into the system and the installation can proceed:
k8s-test.local# rpm --import https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg k8s-test.local# yum install -y kubelet kubeadm kubectl
Once the Kubelet is configured and CRI-O also ready, the CRI-O daemon can be started and the setup of the cluster can be done:
The kubelet will not start successfully until the Kubernetes cluster is installed.
k8s-test.local# systemctl restart crio k8s-test.local# systemctl enable --now kubelet
Installing the Kubernetes cluster
There are multiple ways for installing a Kubernetes cluster, in this example it will be done with the command
kubeadm, the pod network cidr is the same that has been previously used for the CRI-O bridge in the
10-crio-bridge.conf configuration file:
k8s-test.local# kubeadm init --pod-network-cidr=10.244.0.0/16
When the installation finishes the command will print a similar message like this one:
Your Kubernetes control-plane has initialized successfully! To start using your cluster, you need to run the following as a regular user: mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config You should now deploy a pod network to the cluster. Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at: https://kubernetes.io/docs/concepts/cluster-administration/addons/ Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.168.0.10:6443 --token 6fsrbi.iqsw1girupbwue5o \ --discovery-token-ca-cert-hash sha256:c7cf9d9681876856f9b7819067841436831f19004caadab0b5838a9bf7f4126a
Now, it’s time to deploy the pod network. If the reader is curious and want to already check the status of the cluster, the following commands can be executed for getting all the pods running and their status:
k8s-test.local# export KUBECONFIG=/etc/kubernetes/kubelet.conf k8s-test.local# kubectl get pods -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-5644d7b6d9-ffnvx 1/1 Running 0 101s kube-system coredns-5644d7b6d9-lh9gm 1/1 Running 0 101s kube-system etcd-k8s-test 1/1 Running 0 59s kube-system kube-apiserver-k8s-test 1/1 Running 0 54s kube-system kube-controller-manager-k8s-test 1/1 Running 0 58s kube-system kube-proxy-tdcdv 1/1 Running 0 101s kube-system kube-scheduler-k8s-test 1/1 Running 0 50s
Installing the pod network
The Kubernetes pod-network documentation shows different add-on to handle the communications between the pods.
In this example Virtual Machines will be deployed with KubeVirt and also they will have multiple network interfaces attached to the VMs, in this example Multus is going to be used.
Some of the Multus Prerequisites indicate:
After installing Kubernetes, you must install a default network CNI plugin. If you’re using kubeadm, refer to the “Installing a pod network add-on” section in the kubeadm documentation. If it’s your first time, we generally recommend using Flannel for the sake of simplicity.
So flannel is going to be installed running the following commands:
k8s-test.local# cd /root k8s-test.local# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
The version of CNI has to be checked and ensured that is the
0.3.1 version, otherwise, it has to be changed, in this example the version
0.2.0 is replaced by the
k8s-test.local# grep cniVersion kube-flannel.yml "cniVersion": "0.2.0", k8s-test.local# sed -i 's/0.2.0/0.3.1/g' kube-flannel.yml k8s-test.local# kubectl apply -f kube-flannel.yml podsecuritypolicy.policy/psp.flannel.unprivileged created clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.apps/kube-flannel-ds-amd64 created daemonset.apps/kube-flannel-ds-arm64 created daemonset.apps/kube-flannel-ds-arm created daemonset.apps/kube-flannel-ds-ppc64le created daemonset.apps/kube-flannel-ds-s390x created
Once the flannel network has been created the Multus can be defined, to check the status of the pods the following command can be executed:
k8s-test.local# kubectl get pods -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-5644d7b6d9-9mfc9 1/1 Running 0 20h kube-system coredns-5644d7b6d9-sd6ck 1/1 Running 0 20h kube-system etcd-k8s-test 1/1 Running 0 20h kube-system kube-apiserver-k8s-test 1/1 Running 0 20h kube-system kube-controller-manager-k8s-test 1/1 Running 0 20h kube-system kube-flannel-ds-amd64-ml68d 1/1 Running 0 20h kube-system kube-proxy-lqjpv 1/1 Running 0 20h kube-system kube-scheduler-k8s-test 1/1 Running 0 20h
To load the multus configuration, the
multus-cni repository has to be cloned, and also the
kube-1.16-change branch has to be used:
k8s-test.local# git clone https://github.com/intel/multus-cni /root/src/github.com/multus-cni k8s-test.local# cd /root/src/github.com/multus-cni k8s-test.local# git checkout origin/kube-1.16-change k8s-test.local# cd multus-cni/images
To load the multus daemonset the following command has to be executed:
k8s-test.local# kubectl create -f multus-daemonset-crio.yml customresourcedefinition.apiextensions.k8s.io/network-attachment-definitions.k8s.cni.cncf.io created clusterrole.rbac.authorization.k8s.io/multus created clusterrolebinding.rbac.authorization.k8s.io/multus created serviceaccount/multus created configmap/multus-cni-config created daemonset.apps/kube-multus-ds-amd64 created daemonset.apps/kube-multus-ds-ppc64le created
In the next post KubeVirt: requirements and first Virtual Machine, the KubeVirt requirements will be set up together with the binaries and YAML files and also the first virtual Machines will be deployed.