website/docs/setup/independent/install-kubeadm.md

title
Installing kubeadm

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This page shows how to use install kubeadm.

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• One or more machines running Ubuntu 16.04+, Debian 9, CentOS 7, RHEL 7, Fedora 25/26 (best-effort) or HypriotOS v1.0.1+
• 1GB or more of RAM per machine (any less will leave little room for your apps)
• Full network connectivity between all machines in the cluster (public or private network is fine)
• Unique MAC address and product_uuid for every node
• Certain ports are open on your machines. See the section below for more details
• Swap disabled. You must disable swap in order for the kubelet to work properly.
• Set /proc/sys/net/bridge/bridge-nf-call-iptables to 1 by running sysctl net.bridge.bridge-nf-call-iptables=1 to pass bridged IPv4 traffic to iptables' chains. This is a requirement for CNI plugins to work, for more information please see here.

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Check required ports

Master node(s)

Port Range	Purpose
6443*	Kubernetes API server
2379-2380	etcd server client API
10250	Kubelet API
10251	kube-scheduler
10252	kube-controller-manager
10255	Read-only Kubelet API (Heapster)

Worker node(s)

Port Range	Purpose
10250	Kubelet API
10255	Read-only Kubelet API (Heapster)
30000-32767	Default port range for NodePort Services. Typically, these ports would need to be exposed to external load-balancers, or other external consumers of the application itself.

Any port numbers marked with * are overridable, so you will need to ensure any custom ports you provide are also open.

Although etcd ports are included in master nodes, you can also host your own etcd cluster externally on custom ports.

The pod network plugin you use (see below) may also require certain ports to be open. Since this differs with each pod network plugin, please see the documentation for the plugins about what port(s) those need.

Installing ebtables ethtool

If you see the following warnings while running kubeadm init

[preflight] WARNING: ebtables not found in system path                          
[preflight] WARNING: ethtool not found in system path                           

Then you may be missing ebtables and ethtool on your Linux machine. You can install them with the following commands:

# For ubuntu/debian users, try 
apt install ebtables ethtool

# For CentOS/Fedora users, try 
yum install ebtables ethtool

Installing Docker

On each of your machines, install Docker. Version v1.12 is recommended, but v1.11, v1.13 and 17.03 are known to work as well. Versions 17.06+ might work, but have not yet been tested and verified by the Kubernetes node team.

You can use the following commands to install Docker on your system:

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Install Docker from Ubuntu's repositories:

apt-get update
apt-get install -y docker.io

or install Docker CE 17.03 from Docker's repositories for Ubuntu or Debian:

apt-get update && apt-get install -y curl apt-transport-https
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/docker.list
deb https://download.docker.com/linux/$(lsb_release -si | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable
EOF
apt-get update && apt-get install -y docker-ce=$(apt-cache madison docker-ce | grep 17.03 | head -1 | awk '{print $3}')

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Install Docker using your operating system's bundled package:

yum install -y docker
systemctl enable docker && systemctl start docker

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{% assign tab_set_name = "docker_install" %} {% assign tab_names = "Ubuntu, Debian or HypriotOS;CentOS, RHEL or Fedora" | split: ';' | compact %} {% assign tab_contents = site.emptyArray | push: docker_ubuntu | push: docker_centos %}

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Installing kubeadm, kubelet and kubectl

You will install these packages on all of your machines:

• kubeadm: the command to bootstrap the cluster.

• kubelet: the component that runs on all of the machines in your cluster and does things like starting pods and containers.

• kubectl: the command line util to talk to your cluster.

Please proceed with executing the following commands based on your OS as root. You may become the root user by executing sudo -i after SSH-ing to each host.

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apt-get update && apt-get install -y apt-transport-https
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y kubelet kubeadm kubectl

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cat <<EOF > /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
EOF
setenforce 0
yum install -y kubelet kubeadm kubectl
systemctl enable kubelet && systemctl start kubelet

Note:

• Disabling SELinux by running setenforce 0 is required to allow containers to access the host filesystem, which is required by pod networks for example. You have to do this until SELinux support is improved in the kubelet.

• Some users on RHEL/CentOS 7 have reported issues with traffic being routed incorrectly due to iptables being bypassed. You should ensure net.bridge.bridge-nf-call-iptables is set to 1 in your sysctl config, e.g.

  cat <<EOF >  /etc/sysctl.d/k8s.conf
  net.bridge.bridge-nf-call-ip6tables = 1
  net.bridge.bridge-nf-call-iptables = 1
  EOF
  sysctl --system
  

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{% assign tab_set_name = "k8s_install" %} {% assign tab_names = "Ubuntu, Debian or HypriotOS;CentOS, RHEL or Fedora" | split: ';' | compact %} {% assign tab_contents = site.emptyArray | push: ubuntu | push: centos %}

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The kubelet is now restarting every few seconds, as it waits in a crashloop for kubeadm to tell it what to do.

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• Using kubeadm to Create a Cluster

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