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Fedora (Single Node)

• Prerequisites
• Instructions
• Support Level

Prerequisites

1. You need 2 or more machines with Fedora installed.

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.
• The –enablerepo=updates-testing directive in the yum command below will ensure that the most recent Kubernetes version that is scheduled for pre-release will be installed. This should be a more recent version than the Fedora “stable” release for Kubernetes that you would get without adding the directive.
• If you want the very latest Kubernetes release you can download and yum install the RPM directly from Fedora Koji instead of using the yum install command below.

yum -y install --enablerepo=updates-testing kubernetes

• Install etcd and iptables

yum -y install etcd iptables

• 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 will be the same on all hosts (master and node) to contain:

# Comma separated list of nodes in the etcd cluster
KUBE_MASTER="--master=http://fed-master:8080"

# logging to stderr means we get it in the systemd journal
KUBE_LOGTOSTDERR="--logtostderr=true"

# journal message level, 0 is debug
KUBE_LOG_LEVEL="--v=0"

# Should this cluster be allowed to run privileged docker containers
KUBE_ALLOW_PRIV="--allow-privileged=false"

• 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://127.0.0.1:4001"

# 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,let the etcd to listen all the ip instead of 127.0.0.1, if not, you will get the error like “connection refused”. Note that Fedora 22 uses etcd 2.0, One of the changes in etcd 2.0 is that now uses port 2379 and 2380 (as opposed to etcd 0.46 which userd 4001 and 7001).

ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:4001"

• Create /var/run/kubernetes on master:

mkdir /var/run/kubernetes
chown kube:kube /var/run/kubernetes
chmod 750 /var/run/kubernetes

• 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                LABELS              STATUS
fed-node           name=fed-node-label     Unknown

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                LABELS              STATUS
fed-node          name=fed-node-label     Ready

• 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.

You should have a functional cluster, check out 101!

Support Level

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