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Reason: Many missing prompts. (Discuss in Talk:Kubernetes)

Kubernetes (aka. k8s) is an open-source system for automating the deployment, scaling, and management of containerized applications.

A k8s cluster consists of its control-plane components and node components (each representing one or more host machines running a container runtime and kubelet.service). There are two options to install kubernetes, "the real one", described here, and a local install with k3s, kind, or minikube.


There are many methods to setup a kubernetes cluster. This article will focus on bootstrapping with kubeadm.

Deployment tools


When bootstrapping a Kubernetes cluster with kubeadm, install kubeadm and kubelet on each node.

Manual installation

When manually creating a Kubernetes cluster install etcdAUR and the package group kubernetes-control-plane (for a control-plane node) and kubernetes-node (for a worker node).

Cluster management

To control a kubernetes cluster, install kubectl on the control-plane hosts and any external host that is supposed to be able to interact with the cluster.

Container runtime

Both control-plane and regular worker nodes require a container runtime for their kubelet instances which is used for hosting containers. Install either containerd or cri-o to meet this dependency.


To setup forwarding IPv4 and letting iptables see bridged traffic, begin by loading the kernel modules overlay and br_netfilter manually.

To perform this step on subsequent boots, create:


Some module parameters are required:

net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1

Apply them without rebooting with:

# sysctl --system

(Optionally) verify that the br_netfilter, overlay modules are loaded by running the following commands:

lsmod | grep br_netfilter
lsmod | grep overlay

(Optionally) verify that the net.bridge.bridge-nf-call-iptables, net.bridge.bridge-nf-call-ip6tables, and net.ipv4.ip_forward system variables are set to 1 in your sysctl config by running the following command:

sysctl net.bridge.bridge-nf-call-iptables net.bridge.bridge-nf-call-ip6tables net.ipv4.ip_forward

Refer to official document[1] for more details.

Use containerd runtime

There are two methods available to install this package.


To install a rootless containerd, use nerdctl-full-binAUR, which is nerdctl full pkg, bundle with containerd/CNI plugin/RootlessKit:

containerd-rootless-setuptool.sh install

Remember that Arch Linux uses systemd as its init system, so you need to choose systemd cgroup driver before deploying the control plane(s).

Install and configure containerd

Install the containerd package.

(Optional) Create default configuration

This step is not strictly required, but if you find that kubeadm is not initializing due to errors in containerd, try these steps first.

# mkdir -pv /etc/containerd
# cd /etc/containerd
# containerd config default > config.toml
(Optional) Use the systemd cgroup driver

As noted elsewhere in this page, Arch Linux uses systemd, so you will almost certainly need to edit config.toml and change SystemdCgroup = false to SystemdCgroup = true.

Enable and start containerd

Finally enable/start containerd.service.

(Optional) Package manager

helm is a tool for managing pre-configured Kubernetes resources which may be helpful for getting started.


All nodes in a cluster (control-plane and worker) require a running instance of kubelet.service.

Tip: Read the following subsections closely before starting kubelet.service or using kubeadm.

All provided systemd services accept CLI overrides in environment files:

  • kubelet.service: /etc/kubernetes/kubelet.env
  • kube-apiserver.service: /etc/kubernetes/kube-apiserver.env
  • kube-controller-manager.service: /etc/kubernetes/kube-controller-manager.env
  • kube-proxy.service: /etc/kubernetes/kube-proxy.env
  • kube-scheduler.service: /etc/kubernetes/kube-scheduler.env

This article or section needs expansion.

  • Example for setup without kubeadm, using kube-apiserver.service, kube-controller-manager.service, kube-proxy.service and kube-scheduler.service.
  • Example for setup with kubeadm using configuration files.
(Discuss in Talk:Kubernetes)

Disable swap

Kubernetes currently does not support having swap enabled on the system. See KEP-2400: Node system swap support for details.

See Swap#Disabling swap for instructions on how to disable swap.

Choose cgroup driver

To use the systemd cgroup driver in /etc/containerd/config.toml with runc, set

    SystemdCgroup = true

If /etc/containerd/config.toml does not exist, the default configuration can be generated via[2]

containerd config default > /etc/containerd/config.toml

Remember to restart containerd.service to make the change take effect.

See this[3] official document for a deeper discussion on whether to keep cgroupfs driver or use systemd cgroup driver.

Choose container runtime interface (CRI)

A container runtime has to be configured and started, before kubelet.service can make use of it.

You will pass flag --cri-socket with the container runtime interface endpoint to kubeadm init or kubeadm join in order to create or join a cluster.

For example, if you choose containerd as CRI runtime, the flag --cri-socket will be:

kubeadm init --cri-socket /run/containerd/containerd.sock


Before Kubernetes version 1.27.4, when using containerd as container runtime, it is required to provide kubeadm init or kubeadm join with its CRI endpoint. To do so, specify their flag --cri-socket to /run/containerd/containerd.sock[4].

kubeadm join --cri-socket=/run/containerd/containerd.sock

After Kubernetes version 1.27.4, kubeadm will auto detect this CRI for you, flag --cri-socket is only needed when you installed multiple CRI.


This article or section is out of date.

Reason: As of Feb 2024, installing cri-o using this guide is incomplete and does not result it a functional system. kubeadm reached 1.29.1-1 already. What is still needed? (Discuss in Talk:Kubernetes#CRI-O section needs an update)

When using CRI-O as container runtime, it is required to provide kubeadm init or kubeadm join with its CRI endpoint: --cri-socket='unix:///run/crio/crio.sock'

Note: CRI-O by default uses systemd as its cgroup_manager (see /etc/crio/crio.conf). This is not compatible with kubelet us default (cgroupfs) when using kubelet < v1.22.

Change kubelet us default by appending --cgroup-driver='systemd' to the KUBELET_ARGS environment variable in /etc/kubernetes/kubelet.env upon first start (i.e. before using kubeadm init).

Note that the KUBELET_EXTRA_ARGS variable, used by older versions is now no longer read by the default kubelet.service!

When kubeadm updates from 1.19.x to 1.20.x, then it should be possible to use https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/#config-file as explained on https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/#configure-cgroup-driver-used-by-kubelet-on-control-plane-node, as in https://github.com/cri-o/cri-o/pull/4440/files, instead of the above. (TBC, untested.)

After the node has been configured, the CLI flag could (but does not have to) be replaced by a configuration entry for kubelet:

cgroupDriver: 'systemd'

Choose cluster network parameter

Choose a pod CIDR range

The networking setup for the cluster has to be configured for the respective container runtime. This can be done using cni-plugins.

The pod CIDR addresses refer to the IP address range that is assigned to pods within a Kubernetes cluster. When pods are scheduled to run on nodes in the cluster, they are assigned IP addresses from this CIDR range.

The pod CIDR range is specified when deploying a Kubernetes cluster and is confined within the cluster network. It should not overlap with other IP ranges used within the cluster, such as the service CIDR range.

You will pass flag --pod-network-cidr with value of the virtual network's CIDR to kubeadm init or kubeadm join in order to create or join a cluster.

For example:

kubeadm init --pod-network-cidr=''

will set your kubernetes' pod CIDR range to ''.

(Optional) Choose API server advertising address

If your node for control plane is in multiple subnets (for example you may have installed a tailscale tailnet), when initializing the Kubernetes master with kubeadm init, you can specify the IP address that the API server will advertise with the --apiserver-advertise-address flag. This IP address should be accessible to all nodes in your cluster.

(Optional) Choose alternative node network proxy provider

Node proxy provider like kube-proxy is a network proxy that runs on each node in your cluster, maintaining network rules on nodes to allow network communication to your Pods from network sessions inside or outside of your cluster.

By default kubeadm choose kube-proxy as the node proxy that runs on each node in your cluster.

Container Network Interface (CNI) plugins like cilium offer a complete replacement for kube-proxy.

If you want to use cilium's implementation of node network proxy to fully leverage cilium's network policy feature, you should pass flag --skip-phases=addon/kube-proxy to kubeadm init to skip the install of kube-proxy.

Cilium will install a full replacement during its installation. See this[5] for details.

Create cluster

Before creating a new kubernetes cluster with kubeadm start and enable kubelet.service.

Note: kubelet.service will fail (but restart) until configuration for it is present.

This article or section needs expansion.

  • Example for setup without kubeadm, using kube-apiserver.service, kube-controller-manager.service, kube-proxy.service and kube-scheduler.service.
  • Example for setup with kubeadm using configuration files.
(Discuss in Talk:Kubernetes)

kubeadm without config

When creating a new kubernetes cluster with kubeadm a control-plane has to be created before further worker nodes can join it.

  • If the cluster is supposed to be turned into a high availability cluster (a stacked etcd topology) later on kubeadm init needs to be provided with --control-plane-endpoint=<IP or domain> (it is not possible to do this retroactively!).
  • It is possible to use a config file for kubeadm init instead of a set of parameters.

Initialize control-plane

To initialize control-plane, you need pass the following necessary flags to kubeadm init

If run successfully, kubeadm init will have generated configurations for the kubelet and various control-plane components below /etc/kubernetes/ and /var/lib/kubelet/.

Finally, it will output commands ready to be copied and pasted to setup kubectl and make a worker node join the cluster (based on a token, valid for 24 hours).

To use kubectl with the freshly created control-plane node, setup the configuration (either as root or as a normal user):

$ mkdir -p $HOME/.kube
# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
# chown $(id -u):$(id -g) $HOME/.kube/config

Installing CNI plugins (pod network addon)

Note: You must deploy a Container Network Interface (CNI) based Pod network add-on so that your Pods can communicate with each other. Cluster DNS (CoreDNS) will not start up before a network is installed.

Pod network add-on (CNI plugins) implements the Kubernetes network model[6] differently from simple solutions like flannel to more complicated solutions like calico

An increasingly adopted advanced CNI plugin is cilium, which achieves impressive performance with eBPF[7]. To install cilium as CNI plugin, use cilium-cli:

cilium-cli install

For more details on pod network, see this[8] official document.

kubeadm with config

You will most likely find that creating the control plane requires several attempts find the optimal configuration for your particular setup. To make this easier (and the process with kubeadm more repeatable generally), you may run the initialization step using config files.

Tip: Plan on using two config files, one for inits and one for resets to more rapidly test configurations.

Create the init config

You can create this file anywhere, but we will go with /etc/kubeadm for this example.

# mkdir -pv /etc/kubeadm
# cd /etc/kubeadm
# kubeadm config print init-defaults > init.yaml

This will produce the following file.

apiVersion: kubeadm.k8s.io/v1beta3
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  - signing
  - authentication
kind: InitConfiguration
  bindPort: 6443
  criSocket: unix:///var/run/containerd/containerd.sock
  imagePullPolicy: IfNotPresent
  name: node
  taints: null
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
    dataDir: /var/lib/etcd
imageRepository: registry.k8s.io
kind: ClusterConfiguration
kubernetesVersion: 1.29.0
  dnsDomain: cluster.local
scheduler: {}

Most of the default settings should work, though you will need to update a few of them.

Bootstrap token

Create a token with kubeadm token generate and use it instead of token: abcdef.0123456789abcdef in the config.

The advertiseAddress: should be an IPv4 address of a network interface on the control plane being initialized, probably something in the subnet.

Node name

The default node name can either be left at node and added to your local DNS server or hosts file, or you can change it to an address that is routable on your local network. It should be a DNS-compatible hostname, such as kcp01.example.com. This will allow your control plane to be found on your local network when you join other nodes.

Init the cluster

With all of these changes set, we can initialize our cluster.

# kubeadm init --config /etc/kubeadm/init.yaml

This will produce a good amount of output that will provide instructions on how to join nodes to the cluster, update your kubeconfig to interact with the new cluster, and other tasks.

Use calico for CNI config

The last thing you need before you can start adding nodes and running workloads is a properly configured CNI. This example will use calico for that.

# cd /etc/cni/net.d
# curl https://raw.githubusercontent.com/projectcalico/calico/v3.27.2/manifests/calico.yaml -O
# kubectl create -f calico.yaml

If this completes successfully, you are ready to start adding nodes and running workloads on your cluster.

Create the reset config

Just in case kubeadm does not land the init the first time, you can also create a config file for use with the reset command:

# kubeadm config print reset-defaults > /etc/kubeadm/reset.yaml

This will create the following file:

apiVersion: kubeadm.k8s.io/v1beta4
certificatesDir: /etc/kubernetes/pki
criSocket: unix:///var/run/containerd/containerd.sock
kind: ResetConfiguration
Reset a cluster

To reset the cluster back to zero, run the following command:

# kubeadm reset --config /etc/kubeadm/reset.yaml

This can be done as many times as required to sort out your cluster's ideal configuration.

Create the join config

Most likely once you init the cluster you'll be able to join any nodes with the command listed in the output of the init command, but if you happen to run in to trouble it will be helpful to have a join config available on the nodes you're joining. You can either create this file on your control plane, or run the command on nodes that you intend to join to the cluster, we'll assume you did the latter.

# kubeadm config print join-defaults > /etc/kubeadm/join.yaml

This will create the following file.

apiVersion: kubeadm.k8s.io/v1beta3
caCertPath: /etc/kubernetes/pki/ca.crt
    apiServerEndpoint: kcp01.example.com:6443
    token: abcdef.0123456789abcdef
    unsafeSkipCAVerification: true
  timeout: 5m0s
  tlsBootstrapToken: abcdef.0123456789abcdef
kind: JoinConfiguration
  criSocket: unix:///var/run/containerd/containerd.sock
  imagePullPolicy: IfNotPresent
  name: node01.example.com
  taints: null
Note: You'll need to create two different tokens for this configuration file, the first for discovery.bootstrapToken.token and the second for the discovery.tlsBootstrapToken attribute.

Join cluster

With the token information generated in #Create cluster it is possible to make another machine join the cluster as worker node with command kubeadm join.

Remember you need to choose a container runtime interface for working nodes as well by passing flag <SOCKET> to command kubeadm join.

For example:

# kubeadm join <api-server-ip>:<port> --token <token> --discovery-token-ca-cert-hash sha256:<hash> --node-name=<name_of_the_node> --cri-socket=<SOCKET>

To generate new bootstrap token,

kubeadm token create --print-join-command

If you are using Cilium and find the working node remains to be NotReady, check the status of working node using:

kubectl describe node <node-id> --namespace=kube-system

If you found the following condition status:

Type                  Status       Reason
----                  ------       ------
NetworkUnavailable    False        CiliumIsUp
Ready                 False        KubeletNotReady container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:Network plugin returns error: cni plugin not initialized

Restart containerd.service and kubelet.service on the working node

Tips and tricks

Tear down a cluster

When it is necessary to start from scratch, use kubectl to tear down a cluster.

kubectl drain <node name> --delete-local-data --force --ignore-daemonsets

Here <node name> is the name of the node that should be drained and reset. Use kubectl get node -A to list all nodes.

Then reset the node:

# kubeadm reset

Operating from behind a proxy

kubeadm reads the https_proxy, http_proxy, and no_proxy environment variables. Kubernetes internal networking should be included in the latest one, for example

export no_proxy=",,"

where the second one is the default service network CIDR.


kubelet fail to start during kubeadm init phase

Disable swap on the host, otherwise kubelet.service will fail to start.

See #Disable swap for an instruction on how to disable swap.

Failed to get container stats

If kubelet.service emits

Failed to get system container stats for "/system.slice/kubelet.service": failed to get cgroup stats for "/system.slice/kubelet.service": failed to get container info for "/system.slice/kubelet.service": unknown container "/system.slice/kubelet.service"

it is necessary to add configuration for the kubelet (see relevant upstream ticket).

systemCgroups: '/systemd/system.slice'
kubeletCgroups: '/systemd/system.slice'

Pods cannot communicate when using Flannel CNI and systemd-networkd

See upstream bug report.

systemd-networkd assigns a persistent MAC address to every link. This policy is defined in its shipped configuration file /usr/lib/systemd/network/99-default.link. However, Flannel relies on being able to pick its own MAC address. To override systemd-networkd's behaviour for flannel* interfaces, create the following configuration file:



Then restart systemd-networkd.service.

If the cluster is already running, you might need to manually delete the flannel.1 interface and the kube-flannel-ds-* pod on each node, including the master. The pods will be recreated immediately and they themselves will recreate the flannel.1 interfaces.

Delete the interface flannel.1:

# ip link delete flannel.1

Delete the kube-flannel-ds-* pod. Use the following command to delete all kube-flannel-ds-* pods on all nodes:

$ kubectl -n kube-system delete pod -l="app=flannel"

CoreDNS Pod pending forever, the control plane node remains "NotReady"

When bootstrap the Kubernetes with kubeadm init on a single machine, and there is no other machine kubeadm join the cluster, the control-plane node is default to be tainted. As a result, no workload will be scheduled on the working machine.

One can confirm the control-plane node is tainted by the following commands:

kubectl get nodes -o json | jq '.items[].spec.taints

To temporarily allow scheduling on the control-plane node, execute:

kubectl taint nodes <your-node-name> node-role.kubernetes.io/control-plane:NoSchedule-

Then restart containerd.service and kubelet.service to apply the updates.

[kubelet-finalize] malformed header: missing HTTP content-type

You may have forgotten to choose systemd cgroup driver. See this GitHub issue reporting this.

See also