Install Kubernetes 1.31 on Debian 12 with Flannel
Intro
Installation example of Kubernetes Cluster on Debian 11 Hosts used in this sample:
- c3-control-plane
- c3-worker-01
- c3-worker-02
- Host specs:
- VM's with 8CPUs, 16GB Ram each, running Debian12
- Host file example of c2-control-plane
127.0.1.1 c2-control-plane 127.0.0.1 localhost
192.168.2.71 c3-control-plane 192.168.2.88 c3-worker-01 192.168.2.89 c3-worker-02
Installation on Master and on all Nodes
Hostnames
Hostnames used in this Lab, makle sure to add them into /etc/hosts on all machines
- c3-control-plane
- c3-worker-01
- c3-worker-02
Load required modules and set kernel settings
cat << EOF | tee /etc/modules-load.d/containerd.conf overlay br_netfilter EOF
cat << EOF | sudo tee /etc/sysctl.d/99-kubernetes-cri.conf net.ipv4.ip_forward = 1 net.bridge.bridge-nf-call-iptables = 1 net.bridge.bridge-nf-call-ip6tables = 1 EOF
- Turn off swap
sudo sed -i '/swap/d' /etc/fstab
- Apply
modprobe overlay modprobe br_netfilter sysctl --system swapoff -a
- Install an NTP server otherwise etcd will be mad.
apt install -y chrony
Containerd
- Requires the Docker repository
apt install -y curl gpg lsb-release apparmor apparmor-utils curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null
- Update and install
apt update apt-get install -y containerd.io
- Create a default configuration
mkdir -p /etc/containerd containerd config default | tee /etc/containerd/config.toml
- Open /etc/containerd/config.toml
- Search
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
- Underneath add or change to:
SystemdCgroup = true
- Restart and check the service
systemctl restart containerd systemctl status containerd
Kubernetes
Repository
apt-get install -y apt-transport-https ca-certificates curl echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.31/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.31/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg apt-get update
Additional Packages
- Need iptables
apt-get install -y iptables libiptc0/stable libxtables12/stable
- Need the containertools (https://github.com/flannel-io/flannel)
apt-get install containernetworking-plugins
Install and Hold
apt-get install -y kubelet kubeadm kubectl apt-mark hold kubelet kubeadm kubectl
Initialization - MASTER ONLY
Init
ATTENTION As per Flannel requirement: You need to choose the below network
- https://gist.github.com/rkaramandi/44c7cea91501e735ea99e356e9ae7883
- https://stackoverflow.com/questions/48984659/understanding-kubeadm-init-command-for-flannel
root@c3-control-plane:~# sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version 1.31.1 [init] Using Kubernetes version: v1.31.1 [preflight] Running pre-flight checks [preflight] Pulling images required for setting up a Kubernetes cluster [preflight] This might take a minute or two, depending on the speed of your internet connection [preflight] You can also perform this action beforehand using 'kubeadm config images pull' W0924 20:27:37.309409 3434 checks.go:846] detected that the sandbox image "registry.k8s.io/pause:3.8" of the container runtime is inconsistent with that used by kubeadm.It is recommended to use "registry.k8s.io/pause:3.10" as the CRI sandbox image. [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Generating "ca" certificate and key [certs] Generating "apiserver" certificate and key [certs] apiserver serving cert is signed for DNS names [c3-control-plane kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.2.71] [certs] Generating "apiserver-kubelet-client" certificate and key [ certs] Generating "front-proxy-ca" certificate and key [certs] Generating "front-proxy-client" certificate and key [certs] Generating "etcd/ca" certificate and key [certs] Generating "etcd/server" certificate and key [certs] etcd/server serving cert is signed for DNS names [c3-control-plane localhost] and IPs [192.168.2.71 127.0.0.1 ::1] [certs] Generating "etcd/peer" certificate and key [certs] etcd/peer serving cert is signed for DNS names [c3-control-plane localhost] and IPs [192.168.2.71 127.0.0.1 ::1] [certs] Generating "etcd/healthcheck-client" certificate and key [certs] Generating "apiserver-etcd-client" certificate and key [certs] Generating "sa" key and public key [kubeconfig] Using kubeconfig folder "/etc/kubernetes" [kubeconfig] Writing "admin.conf" kubeconfig file [kubeconfig] Writing "super-admin.conf" kubeconfig file [kubeconfig] Writing "kubelet.conf" kubeconfig file [kubeconfig] Writing "controller-manager.conf" kubeconfig file [kubeconfig] Writing "scheduler.conf" kubeconfig file [etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests" [control-plane] Using manifest folder "/etc/kubernetes/manifests" [control-plane] Creating static Pod manifest for "kube-apiserver" [control-plane] Creating static Pod manifest for "kube-controller-manager" [control-plane] Creating static Pod manifest for "kube-scheduler" [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Starting the kubelet [wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests" [kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s [kubelet-check] The kubelet is healthy after 1.002763895s [api-check] Waiting for a healthy API server. This can take up to 4m0s [api-check] The API server is healthy after 7.551840294s [upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config" in namespace kube-system with the configuration for the kubelets in the cluster [upload-certs] Skipping phase. Please see --upload-certs [mark-control-plane] Marking the node c3-control-plane as control-plane by adding the labels: [node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers] [mark-control-plane] Marking the node c3-control-plane as control-plane by adding the taints [node-role.kubernetes.io/control-plane:NoSchedule] [bootstrap-token] Using token: lh8xc6.3sko0430n0rz8awq [bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles [bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to get nodes [bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials [bootstrap-token] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token [bootstrap-token] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster [bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace [kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key [addons] Applied essential addon: CoreDNS [addons] Applied essential addon: kube-proxy Your Kubernetes control-plane has initialized successfully! To start using your cluster, you need to run the following as a regular user: mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config Alternatively, if you are the root user, you can run: export KUBECONFIG=/etc/kubernetes/admin.conf You should now deploy a pod network to the cluster. Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at: https://kubernetes.io/docs/concepts/cluster-administration/addons/ Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.168.2.71:6443 --token lh8xc6.3sko0430n0rz8awq \ --discovery-token-ca-cert-hash sha256:cfc8aa385d1898a567a0370a3b9ed9331aae78e13c9414917fe5f5acb62851df
Regular user setup
Switch to a normal, non root user
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
Before Flannel
Before Flannel
vmadmin@c3-control-plane:~$ kubectl get nodes NAME STATUS ROLES AGE VERSION c3-control-plane NotReady control-plane 35m v1.31.1
Apply Flannel
vmadmin@c3-control-plane:~$ kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml namespace/kube-flannel created serviceaccount/flannel created clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created configmap/kube-flannel-cfg created daemonset.apps/kube-flannel-ds created
After Flannel
After Flannel - This may take a while
vmadmin@c3-control-plane:~$ kubectl get nodes NAME STATUS ROLES AGE VERSION c3-control-plane Ready control-plane 35m v1.31.1
Join the worker nodes
Node01
root@c3-worker-01:~# kubeadm join 192.168.2.71:6443 --token lh8xc6.3sko0430n0rz8awq \ --discovery-token-ca-cert-hash sha256:cfc8aa385d1898a567a0370a3b9ed9331aae78e13c9414917fe5f5acb62851df [preflight] Running pre-flight checks [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Starting the kubelet [kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s [kubelet-check] The kubelet is healthy after 1.002183203s [kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap This node has joined the cluster: * Certificate signing request was sent to apiserver and a response was received. * The Kubelet was informed of the new secure connection details. Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
Node02
root@c3-worker-02:~# kubeadm join 192.168.2.71:6443 --token lh8xc6.3sko0430n0rz8awq \ --discovery-token-ca-cert-hash sha256:cfc8aa385d1898a567a0370a3b9ed9331aae78e13c9414917fe5f5acb62851df [preflight] Running pre-flight checks [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Starting the kubelet [kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s [kubelet-check] The kubelet is healthy after 1.00237113s [kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap This node has joined the cluster: * Certificate signing request was sent to apiserver and a response was received. * The Kubelet was informed of the new secure connection details. Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
Show Results
# kubectl get nodes vmadmin@c3-control-plane:~$ kubectl get nodes NAME STATUS ROLES AGE VERSION c3-control-plane Ready control-plane 32m v1.31.1 c3-worker-01 Ready <none> 4m54s v1.31.1 c3-worker-02 Ready <none> 112s v1.31.1
Optional Labeling
vmadmin@c3-control-plane:~$ kubectl label node c3-worker-01 node-role.kubernetes.io/worker=worker node/c3-worker-01 labeled vmadmin@c3-control-plane:~$ kubectl label node c3-worker-02 node-role.kubernetes.io/worker=worker node/c3-worker-02 labeled vmadmin@c3-control-plane:~$ kubectl get nodes NAME STATUS ROLES AGE VERSION c3-control-plane Ready control-plane 19m v1.31.1 c3-worker-01 Ready worker 8m18s v1.31.1 c3-worker-02 Ready worker 94s v1.31.1
References
- Self installation using calico
https://www.howtoforge.de/anleitung/kubernetes-cluster-mit-kubeadm-auf-debian-11-einrichten/
https://www.linuxtechi.com/install-kubernetes-cluster-on-debian/
https://www.oueta.com/linux/create-a-debian-11-kubernetes-cluster-with-kubeadm/
- About calico
https://www.inovex.de/de/blog/kubernetes-networking-2-calico-cilium-weavenet/#
- Interesting about installation via Ansible:
https://www.linuxsysadmins.com/install-kubernetes-cluster-with-ansible/
- About Container Network Interface (CNI) - Add Ons
https://kubernetes.io/docs/concepts/cluster-administration/addons/
https://platform9.com/blog/the-ultimate-guide-to-using-calico-flannel-weave-and-cilium/
https://kubevious.io/blog/post/comparing-kubernetes-container-network-interface-cni-providers
https://www.linux-magazin.de/ausgaben/2017/08/netz-in-kubernetes/
https://ronaknathani.com/blog/2020/08/how-a-kubernetes-pod-gets-an-ip-address/
- Nice cheat sheet https://spacelift.io/blog/kubernetes-cheat-sheet
- Troubleshoot Flannel
https://www.continualintegration.com/miscellaneous-articles/how-do-you-solve-the-kubernetes-error-networkplugin-cni-failed-to-set-up-pod-network-open-run-flannel-subnet-env-no-such-file-or-directory/
https://www.programmersought.com/article/7824768991/
- Continue from Flannel
https://github.com/Thoorium/kubernetes-local-cluster-flannel-metallb-traefik