This is a getting started guide for Fedora. It is a manual configuration so you understand all the underlying packages / services / ports, etc…
This guide will only get ONE node (previously minion) working. Multiple nodes require a functional networking configuration done outside of Kubernetes. Although the additional Kubernetes configuration requirements should be obvious.
The Kubernetes package provides a few services: kube-apiserver, kube-scheduler, kube-controller-manager, kubelet, kube-proxy. These services are managed by systemd and the configuration resides in a central location:
/etc/kubernetes. We will break the services up between the hosts. The first host, fed-master, will be the Kubernetes master. This host will run the kube-apiserver, kube-controller-manager, and kube-scheduler. In addition, the master will also run etcd (not needed if etcd runs on a different host but this guide assumes that etcd and Kubernetes master run on the same host). The remaining host, fed-node will be the node and run kubelet, proxy and docker.
fed-master = 192.168.121.9 fed-node = 192.168.121.65
Prepare the hosts:
Running on AWS EC2 with RHEL 7.2, you need to enable “extras” repository for yum by editing
/etc/yum.repos.d/redhat-rhui.repo and changing the
enable=1 for extras.
dnf -y install kubernetes
dnf -y install etcd
Add master and node to
/etc/hosts on all machines (not needed if hostnames already in DNS). Make sure that communication works between fed-master and fed-node by using a utility such as ping.
echo "192.168.121.9 fed-master 192.168.121.65 fed-node" >> /etc/hosts
/etc/kubernetes/config (which should be the same on all hosts) to set
the name of the master server:
# Comma separated list of nodes in the etcd cluster KUBE_MASTER="--master=http://fed-master:8080"
Disable the firewall on both the master and node, as Docker does not play well with other firewall rule managers. Please note that iptables.service does not exist on the default Fedora Server install.
systemctl mask firewalld.service systemctl stop firewalld.service systemctl disable --now iptables.service
Configure the Kubernetes services on the master.
/etc/kubernetes/apiserver to appear as such. The service-cluster-ip-range IP addresses must be an unused block of addresses, not used anywhere else. They do not need to be routed or assigned to anything.
# The address on the local server to listen to. KUBE_API_ADDRESS="--address=0.0.0.0" # Comma separated list of nodes in the etcd cluster KUBE_ETCD_SERVERS="--etcd-servers=http://127.0.0.1:2379" # Address range to use for services KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16" # Add your own! KUBE_API_ARGS=""
/etc/etcd/etcd.conf to let etcd listen on all available IPs instead of 127.0.0.1. If you have not done this, you might see an error such as “connection refused”.
Start the appropriate services on master:
for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do systemctl enable --now $SERVICES systemctl status $SERVICES done
Configure the Kubernetes services on the node.
We need to configure the kubelet on the node.
/etc/kubernetes/kubelet to appear as such:
### # Kubernetes kubelet (node) config # The address for the info server to serve on (set to 0.0.0.0 or "" for all interfaces) KUBELET_ADDRESS="--address=0.0.0.0" # You may leave this blank to use the actual hostname KUBELET_HOSTNAME="--hostname-override=fed-node" # location of the api-server KUBELET_ARGS="--cgroup-driver=systemd --kubeconfig=/etc/kubernetes/master-kubeconfig.yaml"
/etc/kubernetes/master-kubeconfig.yaml to contain the following information:
kind: Config clusters: - name: local cluster: server: http://fed-master:8080 users: - name: kubelet contexts: - context: cluster: local user: kubelet name: kubelet-context current-context: kubelet-context
Start the appropriate services on the node (fed-node).
for SERVICES in kube-proxy kubelet docker; do systemctl enable --now $SERVICES systemctl status $SERVICES done
Check to make sure now the cluster can see the fed-node on fed-master, and its status changes to Ready.
kubectl get nodes NAME STATUS AGE VERSION fed-node Ready 4h
Deletion of nodes:
To delete fed-node from your Kubernetes cluster, one should run the following on fed-master (Please do not do it, it is just for information):
kubectl delete -f ./node.json
You should be finished!
The cluster should be running! Launch a test pod.
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