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##Getting started on Fedora

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 etcd and docker. This guide has been tested with kubernetes-0.12.0 but should work with later versions too.
yum -y install --enablerepo=updates-testing kubernetes
  • 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 portal_net 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://fed-master:4001"

# Address range to use for services
KUBE_SERVICE_ADDRESSES="--portal_net=10.254.0.0/16"

# Add you own!
KUBE_API_ARGS=""
  • 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:

{
  "id": "fed-node",
  "kind": "Minion",
  "apiVersion": "v1beta1",
  "labels": {
    "name": "fed-node-label"
  }
}

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 id) 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!