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Fedora (Single Node)

• Prerequisites
• Instructions
• Support Level

Prerequisites

1. You need 2 or more machines with Fedora installed. These can be either bare metal machines or virtual machines.

Instructions

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.

System Information:

Hosts:

fed-master = 192.168.121.9
fed-node = 192.168.121.65

Prepare the hosts:

• Install Kubernetes on all hosts - fed-{master,node}. This will also pull in docker. Also install etcd on fed-master. This guide has been tested with Kubernetes-0.18 and beyond.
• 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 changing the enable=0 to enable=1 for extras.

dnf -y install kubernetes

• Install etcd

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

• Edit /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-services does not exist on default fedora server install.

systemctl disable iptables-services firewalld
systemctl stop iptables-services firewalld

Configure the Kubernetes services on the master.

• Edit /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=""

• Edit /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”.

ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379"

• Start the appropriate services on master:

for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do
    systemctl restart $SERVICES
    systemctl enable $SERVICES
    systemctl status $SERVICES
done

• Addition of nodes:

• Create following node.json file on Kubernetes master node:

{
    "apiVersion": "v1",
    "kind": "Node",
    "metadata": {
        "name": "fed-node",
        "labels":{ "name": "fed-node-label"}
    },
    "spec": {
        "externalID": "fed-node"
    }
}

Now create a node object internally in your Kubernetes cluster by running:

$ kubectl create -f ./node.json

$ kubectl get nodes
NAME            STATUS        AGE      VERSION
fed-node        Unknown       4h

Please note that in the above, it only creates a representation for the node fed-node internally. It does not provision the actual fed-node. Also, it is assumed that fed-node (as specified in name) can be resolved and is reachable from Kubernetes master node. This guide will discuss how to provision a Kubernetes node (fed-node) below.

Configure the Kubernetes services on the node.

We need to configure the kubelet on the node.

• Edit /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_API_SERVER="--api-servers=http://fed-master:8080"

# Add your own!
#KUBELET_ARGS=""

• Start the appropriate services on the node (fed-node).

for SERVICES in kube-proxy kubelet docker; do 
    systemctl restart $SERVICES
    systemctl enable $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.

Support Level

For support level information on all solutions, see the Table of solutions chart.