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How to install kubernetes master control-plane on ubuntu Part 1

If you’re using containers, there’s a great possibility you’ve heard of Kubernetes, or K8s (in short). In straightforward language, Kubernetes is an open-source system for orchestrating, automating deployment, scaling, and management of containerized applications. Kubernetes is a tool intended to get your life to lot simpler. Once your infrastructure grows larger and becomes complicated your applications to develop; further Kubernetes is helpful. 

This is in-detailed step by step guide to install kubernetes cluster on Ubuntu OS (linux). There are master node and worker node in the kubernetes architecture, Here I am installing my first master node - control-plane (with roles apiserver, controller manager, scheduler, etcd database). 

kubernetes control plane architecture cluster node

I have my ubuntu servers ready installed, I have assigned static IP and hostname (k8smaster01) to first node. I am running sudo su - to get root access so I don't have to type sudo in front of every command. Do the OS update and upgrade with apt-get update and apt-get upgrade. Install the required application for first phase sudo apt-get install curl apt-transport-https vim wget -y. Package apt-transport-https enables working with http and https in Ubuntu’s repositories, package curl and wget helps to browse and download from internet. Package vim is a text editor.

Command curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - adds kubernetes singing key to Ubuntu node. Add kubernetes repository to ubuntu apt-get package source using echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list.

ubuntu@k8smaster01:~$
ubuntu@k8smaster01:~$ sudo su -
root@k8smaster01:~#
root@k8smaster01:~# apt-get update
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:4 http://security.ubuntu.com/ubuntu focal-security InRelease
Reading package lists... Done
root@k8smaster01:~#
root@k8smaster01:~# apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@k8smaster01:~#
root@k8smaster01:~# sudo apt-get install curl apt-transport-https vim wget -y
Reading package lists... Done
Building dependency tree
Reading state information... Done
curl is already the newest version (7.68.0-1ubuntu2.13).
vim is already the newest version (2:8.1.2269-1ubuntu5.9).
wget is already the newest version (1.20.3-1ubuntu2).
apt-transport-https is already the newest version (2.0.9).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@k8smaster01:~#
root@k8smaster01:~#
root@k8smaster01:~# curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
OK
root@k8smaster01:~#
root@k8smaster01:~# echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
root@k8smaster01:~#

Microsoft kubernetes k8s k3d sudo su - apt-get ubuntu aks eks azure kubernetes services curl instlal apt-transport-https vim wget pod deployment goolg cloud xenial manifest master worker kubeadm kubelet kube-proxy coredns.png

I have added kubernetes online repository in the apt package source, update the repository with command apt-get update -y. Disable swap memory in os kubernetes don't like  where swap is enabled, use command swapoff -a.

Install kubernetes application components apt-get install kubectl kubeadm kubelet kubernetes-cni -y.

kubectl: Command line tool to connect kubernetes cluster and manage.
kubeadm: Using this command you create and initialize kubernetes cluster
kubelet: It is a agent runs on all nodes and handles communication between nodes (runtime).
kubernetes-cni: Enables networking between containers.

root@k8smaster01:~# apt-get update -y && apt-get upgrade -y
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:4 http://security.ubuntu.com/ubuntu focal-security InRelease
Get:5 https://packages.cloud.google.com/apt kubernetes-xenial InRelease [9,383 B]
Get:6 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 Packages [60.1 kB]
Fetched 69.5 kB in 2s (29.8 kB/s)
Reading package lists... Done
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@k8smaster01:~#
root@k8smaster01:~# swapoff -a
root@k8smaster01:~#
root@k8smaster01:~# apt-get install kubectl kubeadm kubelet kubernetes-cni -y
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  conntrack cri-tools ebtables socat
Suggested packages:
  nftables
The following NEW packages will be installed:
  conntrack cri-tools ebtables kubeadm kubectl kubelet kubernetes-cni socat
0 upgraded, 8 newly installed, 0 to remove and 0 not upgraded.
Need to get 81.6 MB of archives.
After this operation, 327 MB of additional disk space will be used.
Get:2 http://us.archive.ubuntu.com/ubuntu focal/main amd64 conntrack amd64 1:1.4.5-2 [30.3 kB]
Get:5 http://us.archive.ubuntu.com/ubuntu focal/main amd64 ebtables amd64 2.0.11-3build1 [80.3 kB]
Get:1 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 cri-tools amd64 1.25.0-00 [17.9 MB]
Get:8 http://us.archive.ubuntu.com/ubuntu focal/main amd64 socat amd64 1.7.3.3-2 [323 kB]
Get:3 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubernetes-cni amd64 1.1.1-00 [25.0 MB]
Get:4 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubelet amd64 1.25.2-00 [19.5 MB]
Get:6 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubectl amd64 1.25.2-00 [9,503 kB]
Get:7 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubeadm amd64 1.25.2-00 [9,219 kB]
Fetched 81.6 MB in 2s (46.6 MB/s)
Selecting previously unselected package conntrack.
(Reading database ... 184093 files and directories currently installed.)
Preparing to unpack .../0-conntrack_1%3a1.4.5-2_amd64.deb ...
Unpacking conntrack (1:1.4.5-2) ...
Selecting previously unselected package cri-tools.
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Unpacking cri-tools (1.25.0-00) ...
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Unpacking ebtables (2.0.11-3build1) ...
Selecting previously unselected package kubernetes-cni.
Preparing to unpack .../3-kubernetes-cni_1.1.1-00_amd64.deb ...
Unpacking kubernetes-cni (1.1.1-00) ...
Selecting previously unselected package socat.
Preparing to unpack .../4-socat_1.7.3.3-2_amd64.deb ...
Unpacking socat (1.7.3.3-2) ...
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Unpacking kubelet (1.25.2-00) ...
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Preparing to unpack .../6-kubectl_1.25.2-00_amd64.deb ...
Unpacking kubectl (1.25.2-00) ...
Selecting previously unselected package kubeadm.
Preparing to unpack .../7-kubeadm_1.25.2-00_amd64.deb ...
Unpacking kubeadm (1.25.2-00) ...
Setting up conntrack (1:1.4.5-2) ...
Setting up kubectl (1.25.2-00) ...
Setting up ebtables (2.0.11-3build1) ...
Setting up socat (1.7.3.3-2) ...
Setting up cri-tools (1.25.0-00) ...
Setting up kubernetes-cni (1.1.1-00) ...
Setting up kubelet (1.25.2-00) ...
Created symlink /etc/systemd/system/multi-user.target.wants/kubelet.service → /lib/systemd/system/kubelet.service.
Setting up kubeadm (1.25.2-00) ...
Processing triggers for man-db (2.9.1-1) ...
root@k8smaster01:~#

Linux Ubuntu install kubernetes cluster control plane swapoff apt-get kubectl kubeadm kubelet kubectl kubernetes-cni dependancy cri-tools docker containerization orchestration upgrade apt-get update.png

Disable swap using vim /etc/fstab with this one more step and comment out the line where swap name contains.

Microsoft azure aks eks cat etc fstab dev mapper swap swapoff kubernetes installation k8s docker containerd virtulization containerization orchestration initialization kubeadm kubelet.png

root@k8smaster01:~# vim /etc/fstab
root@k8smaster01:~#
root@k8smaster01:~#
root@k8smaster01:~# cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/mapper/vgubuntu-root /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/sda1 during installation
UUID=74F0-E06C  /boot/efi       vfat    umask=0077      0       1
#/dev/mapper/vgubuntu-swap_1 none            swap    sw              0       0
root@k8smaster01:~#

This is how the file looks inside the vim editor after disabling swap.

Microsoft windows docker static file system configuration kubernetes k8s k3d swap swapoff -a docker containerization container cka orchestration vgubuntu linux pod deployment sts secret cni.png

Ensure bridged network can be viewed by master and worker nodes. Check the status and see required module is loaded, use commands lsmod | grep br_netfilter and modprobe br_netfilter. To enable it command is sysctl net.bridge.bridge-nf-call-iptables=1.

Kubernetes cluster installation lsmod grep br_netfilter modprobe sysctl net.bridge.bridege-nf-call-iptables k8s k3d docker container orchestration pod deployment pv pvc persistant volume claime.png

root@k8smaster01:~#
root@k8smaster01:~# lsmod | grep br_netfilter
root@k8smaster01:~#
root@k8smaster01:~# modprobe br_netfilter
root@k8smaster01:~#
root@k8smaster01:~# sysctl net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-iptables = 1
root@k8smaster01:~#
root@k8smaster01:~# lsmod | grep br_netfilter
br_netfilter           28672  0
bridge                307200  1 br_netfilter
root@k8smaster01:~#
root@k8smaster01:~# modprobe br_netfilter
root@k8smaster01:~#

Now prepare node to install Docker runtime on the ubuntu system. Install supporting packages using apt-get install ca-certificates gnupg lsb-release. Package ca-certificates is a digital certificate that is used to verify the identity of 3rd parties, and encrypt data between you and said 3rd party. Package gnupg allows you to encrypt and sign your data and communications; it features a versatile key management system, along with access modules for all kinds of public key directories. The lsb_release command prints certain LSB (Linux Standard Base) and Distribution information.

Add docker signing key to ubuntu node using curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg. Add docker package repository inside ubuntu apt-get repo with command echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null. Update apt-get package source repository apt-get update -y. I see repos are added.

apt-get install ca-certificates gnupg lsb-release curl docker containerd cri-o rkt rocket deb soruce apt-get kubernetes k8s installation master control-plane apiserver replication controller scheduler etcd ctl kubectl.png

root@k8smaster01:~#
root@k8smaster01:~# apt-get install ca-certificates gnupg lsb-release
Reading package lists... Done
Building dependency tree
Reading state information... Done
lsb-release is already the newest version (11.1.0ubuntu2).
lsb-release set to manually installed.
ca-certificates is already the newest version (20211016~20.04.1).
ca-certificates set to manually installed.
gnupg is already the newest version (2.2.19-3ubuntu2.2).
gnupg set to manually installed.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@k8smaster01:~#
root@k8smaster01:~# curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
root@k8smaster01:~#
root@k8smaster01:~# echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
>   $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
root@k8smaster01:~#
root@k8smaster01:~# sudo apt-get update -y
Get:1 https://download.docker.com/linux/ubuntu focal InRelease [57.7 kB]
Hit:2 http://us.archive.ubuntu.com/ubuntu focal InRelease
Get:4 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:5 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Get:6 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Get:3 https://packages.cloud.google.com/apt kubernetes-xenial InRelease [9,383 B]
Get:7 https://download.docker.com/linux/ubuntu focal/stable amd64 Packages [18.5 kB]
Fetched 422 kB in 3s (168 kB/s)
Reading package lists... Done
root@k8smaster01:~#

Install Docker/Containerd runtime with sudo apt-get install docker-ce docker-ce-cli containerd.io -y. Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications.

Microsoft Azure aks kubernetes services as services download docker images docker-ce-cli focal packages k8s k3d plugins modules container orchestration sworm sts statefulset daemonsets deployment services clusterip ngress.png

root@k8smaster01:~# sudo apt-get install docker-ce docker-ce-cli containerd.io -y
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  docker-ce-rootless-extras docker-scan-plugin git git-man liberror-perl pigz slirp4netns
Suggested packages:
  aufs-tools cgroupfs-mount | cgroup-lite git-daemon-run | git-daemon-sysvinit git-doc git-el git-email git-gui gitk gitweb git-cvs git-mediawiki git-svn
The following NEW packages will be installed:
  containerd.io docker-ce docker-ce-cli docker-ce-rootless-extras docker-scan-plugin git git-man liberror-perl pigz slirp4netns
0 upgraded, 10 newly installed, 0 to remove and 0 not upgraded.
Need to get 108 MB of archives.
After this operation, 436 MB of additional disk space will be used.
Get:1 https://download.docker.com/linux/ubuntu focal/stable amd64 containerd.io amd64 1.6.8-1 [28.1 MB]
Get:2 http://us.archive.ubuntu.com/ubuntu focal/universe amd64 pigz amd64 2.4-1 [57.4 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu focal/main amd64 liberror-perl all 0.17029-1 [26.5 kB]
Get:4 http://us.archive.ubuntu.com/ubuntu focal-updates/main amd64 git-man all 1:2.25.1-1ubuntu3.5 [886 kB]
Get:5 http://us.archive.ubuntu.com/ubuntu focal-updates/main amd64 git amd64 1:2.25.1-1ubuntu3.5 [4,557 kB]
Get:6 http://us.archive.ubuntu.com/ubuntu focal/universe amd64 slirp4netns amd64 0.4.3-1 [74.3 kB]
Get:7 https://download.docker.com/linux/ubuntu focal/stable amd64 docker-ce-cli amd64 5:20.10.18~3-0~ubuntu-focal [41.5 MB]
Get:8 https://download.docker.com/linux/ubuntu focal/stable amd64 docker-ce amd64 5:20.10.18~3-0~ubuntu-focal [20.4 MB]
Get:9 https://download.docker.com/linux/ubuntu focal/stable amd64 docker-ce-rootless-extras amd64 5:20.10.18~3-0~ubuntu-focal [8,392 kB]
Get:10 https://download.docker.com/linux/ubuntu focal/stable amd64 docker-scan-plugin amd64 0.17.0~ubuntu-focal [3,521 kB]
Fetched 108 MB in 3s (37.7 MB/s)
Selecting previously unselected package pigz.
(Reading database ... 184186 files and directories currently installed.)
Preparing to unpack .../0-pigz_2.4-1_amd64.deb ...
Unpacking pigz (2.4-1) ...
Selecting previously unselected package containerd.io.
Preparing to unpack .../1-containerd.io_1.6.8-1_amd64.deb ...
Unpacking containerd.io (1.6.8-1) ...
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Preparing to unpack .../2-docker-ce-cli_5%3a20.10.18~3-0~ubuntu-focal_amd64.deb ...
Unpacking docker-ce-cli (5:20.10.18~3-0~ubuntu-focal) ...
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Preparing to unpack .../7-git-man_1%3a2.25.1-1ubuntu3.5_all.deb ...
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Preparing to unpack .../8-git_1%3a2.25.1-1ubuntu3.5_amd64.deb ...
Unpacking git (1:2.25.1-1ubuntu3.5) ...
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Preparing to unpack .../9-slirp4netns_0.4.3-1_amd64.deb ...
Unpacking slirp4netns (0.4.3-1) ...
Setting up slirp4netns (0.4.3-1) ...
Setting up docker-scan-plugin (0.17.0~ubuntu-focal) ...
Setting up liberror-perl (0.17029-1) ...
Setting up containerd.io (1.6.8-1) ...
Created symlink /etc/systemd/system/multi-user.target.wants/containerd.service → /lib/systemd/system/containerd.service.
Setting up docker-ce-cli (5:20.10.18~3-0~ubuntu-focal) ...
Setting up pigz (2.4-1) ...
Setting up git-man (1:2.25.1-1ubuntu3.5) ...
Setting up docker-ce-rootless-extras (5:20.10.18~3-0~ubuntu-focal) ...
Setting up docker-ce (5:20.10.18~3-0~ubuntu-focal) ...
Created symlink /etc/systemd/system/multi-user.target.wants/docker.service → /lib/systemd/system/docker.service.
Created symlink /etc/systemd/system/sockets.target.wants/docker.socket → /lib/systemd/system/docker.socket.
Setting up git (1:2.25.1-1ubuntu3.5) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for systemd (245.4-4ubuntu3.18) ...
root@k8smaster01:~#

If folder does not exists /etc/docker create one with mkdir /etc/docker. Docker installs “cgroupfs” as the cgroup driver. Kubernetes recommends that Docker should run with “systemd” as the driver. Use below command to create daemon.json file, below is the configuration file.

cat <<EOF | sudo tee /etc/docker/daemon.json
{ "exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts":
{ "max-size": "100m" },
"storage-driver": "overlay2"
}
EOF

Command systemctl enable docker will make sure it auto start docker daemon after every reboot. Start docker service using systemctl restart docker and check status with systemctl status docker.

etc docker mkdir daemon containerd cgroupdriver systemd systemctl kubernetes kubeadm kubectl kubelet kube-proxy k8s k3d kube apt-get aks azure kuberenetes services acr container registry.png

root@k8smaster01:~# mkdir /etc/docker
mkdir: cannot create directory ‘/etc/docker’: File exists
root@k8smaster01:~#
root@k8smaster01:~# cat <<EOF | sudo tee /etc/docker/daemon.json
> { "exec-opts": ["native.cgroupdriver=systemd"],
> "log-driver": "json-file",
> "log-opts":
> { "max-size": "100m" },
> "storage-driver": "overlay2"
> }
> EOF
{ "exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts":
{ "max-size": "100m" },
"storage-driver": "overlay2"
}
root@k8smaster01:~#
root@k8smaster01:~#
root@k8smaster01:~# systemctl enable docker
Synchronizing state of docker.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable docker
root@k8smaster01:~#
root@k8smaster01:~# systemctl start docker
root@k8smaster01:~#
root@k8smaster01:~# systemctl status docker
● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
     Active: active (running) since Sun 2022-09-25 14:25:45 IST; 21min ago
TriggeredBy: ● docker.socket
       Docs: https://docs.docker.com
   Main PID: 141281 (dockerd)
      Tasks: 8
     Memory: 21.7M
     CGroup: /system.slice/docker.service
             └─141281 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
​Sep 25 14:25:44 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:44.866260223+05:30" level=warning msg="Your kernel does not support CPU realtime scheduler"
Sep 25 14:25:44 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:44.866290980+05:30" level=warning msg="Your kernel does not support cgroup blkio weight"
Sep 25 14:25:44 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:44.866304552+05:30" level=warning msg="Your kernel does not support cgroup blkio weight_device"
Sep 25 14:25:44 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:44.867240439+05:30" level=info msg="Loading containers: start."
Sep 25 14:25:45 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:45.338255004+05:30" level=info msg="Default bridge (docker0) is assigned with an IP address 172.1>
Sep 25 14:25:45 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:45.522733102+05:30" level=info msg="Loading containers: done."
Sep 25 14:25:45 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:45.643885527+05:30" level=info msg="Docker daemon" commit=e42327a graphdriver(s)=overlay2 version>
Sep 25 14:25:45 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:45.644876492+05:30" level=info msg="Daemon has completed initialization"
Sep 25 14:25:45 k8smaster01 systemd[1]: Started Docker Application Container Engine.
Sep 25 14:25:45 k8smaster01 dockerd[141281]: time="2022-09-25T14:25:45.687264393+05:30" level=info msg="API listen on /run/docker.sock"
root@k8smaster01:~#

Create a folder /etc/containerd with mkdir -p /etc/containerd. Configure containerd service and restart it with containerd config default > /etc/containerd/config.toml and restart deamon systemctl restart containerd.

Kubernetes resources kubeadm installation containerd config runtime config toml yaml yml metadata manifest aks k8s k3d netflix.png

root@k8smaster01:~#
root@k8smaster01:~# mkdir -p /etc/containerd
root@k8smaster01:~# containerd config default > /etc/containerd/config.toml
root@k8smaster01:~#
root@k8smaster01:~# systemctl restart containerd
root@k8smaster01:~#

Platform is ready to deploy kubernetes cluster with the command kubeadm init --pod-network-cidr=10.244.0.0/16. This will initialize the first kubernetes master in the cluster. Note down kubernetes join command which I will use in next article to join kubernetes worker node to master in the cluster.

Kubernetes k8s kubeadm init cidr kubelet kube-proxy kube-apiserver kube-controller-manager kube-scheduler bootstrap rbac rules coredns kubeconfig podnetwork configmap token discovery jon cert hash.png

root@k8smaster01:~#
root@k8smaster01:~# kubeadm init --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.25.2
[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 in beforehand using 'kubeadm config images pull'
[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 [k8smaster01 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.34.61]
[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 [k8smaster01 localhost] and IPs [192.168.34.61 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8smaster01 localhost] and IPs [192.168.34.61 127.0.0.1 ::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 "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[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
[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"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 14.004808 seconds
[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 k8smaster01 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 k8smaster01 as control-plane by adding the taints [node-role.kubernetes.io/control-plane:NoSchedule]
[bootstrap-token] Using token: pryngq.9uyua66107320l6a
[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 192.168.34.61:6443 --token pryngq.9uyua66107320l6a \
        --discovery-token-ca-cert-hash sha256:1a7ce7f1bbbdac289749e0b4c62c6bba3eae98f9678fa710a97e96e26b4d8d92
Enable firewall node to allow 6443 TCP port. By default, the Kubernetes API server listens on port 6443 on the first non-localhost network interface, protected by TLS.

kubernetes firewaall ufw allow 6443 ssl tcp rules sudo k8s k3d docker container orchestration virtualization vmware vshere openshift automation devops kubeadm init configuration aks.png

root@k8smaster01:~# sudo ufw allow 6443
Rules updated
Rules updated (v6)
root@k8smaster01:~# sudo ufw allow 6443/tcp

Rules updated
Rules updated (v6)
root@k8smaster01:~#

Kubernetes cluster with first master node and control-plane is installed successfully. Use kubectl get nodes to connect k8s cluster and get the nodes list. It will error as I haven't setup kubeconfig file to connect to kubernetes cluster yet. Use the command as mentioned after running kubeadm init command to setup kubeconfig file

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

Verify nodes, I am able to connect it successfully. There is only one node with control-plane not ready status.

kubernetes kubectl get nodes locallhost 8080 refused port chown notready cluster kubernetes control-plane version internal ip external ip kubeconfig.png

root@k8smaster01:~#
root@k8smaster01:~# kubectl get nodes
The connection to the server localhost:8080 was refused - did you specify the right host or port?
root@k8smaster01:~#
root@k8smaster01:~# mkdir -p $HOME/.kube
root@k8smaster01:~# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
root@k8smaster01:~# sudo chown $(id -u):$(id -g) $HOME/.kube/config
root@k8smaster01:~#
root@k8smaster01:~# kubectl get nodes
NAME          STATUS     ROLES           AGE   VERSION
k8smaster01   NotReady   control-plane   14m   v1.25.2
root@k8smaster01:~#

Check the pods status inside kube-system with command kubectl get pods -n kube-system -o wide. There is coredns pods which are in pending status, it need to be fix.

Kubernetes kubectl get pod kube-system public coredns etcd apiserver controller manager kube-proxy scheduler master node worker control-plane pending running ready failed error imagepullback.png

root@k8smaster01:~# kubectl get pods -n kube-system -o wide
NAME                                  READY   STATUS    RESTARTS   AGE   IP              NODE          NOMINATED NODE   READINESS GATES
coredns-565d847f94-8vqbx              0/1     Pending   0          32m   <none>          <none>        <none>           <none>
coredns-565d847f94-w6ms8              0/1     Pending   0          32m   <none>          <none>        <none>           <none>
etcd-k8smaster01                      1/1     Running   0          32m   192.168.34.61   k8smaster01   <none>           <none>
kube-apiserver-k8smaster01            1/1     Running   0          32m   192.168.34.61   k8smaster01   <none>           <none>
kube-controller-manager-k8smaster01   1/1     Running   0          32m   192.168.34.61   k8smaster01   <none>           <none>
kube-proxy-vdtn9                      1/1     Running   0          32m   192.168.34.61   k8smaster01   <none>           <none>
kube-scheduler-k8smaster01            1/1     Running   0          32m   192.168.34.61   k8smaster01   <none>           <none>
root@k8smaster01:~#

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. Also there won't be pod communication working until you have networking in place.

For this I am using project calico networking cni plugin. Use command kubectl create -f https://docs.projectcalico.org/manifests/tigera-operator.yaml. Next download one more k8s manifest using command wget https://docs.projectcalico.org/manifests/custom-resources.yaml. Edit file with command vim custom-resources.yaml. change the section cidr with the earlier used IP block while installing kubernetes cluster using kubeadm init - 10.244.0.0/16. Once the file is edited create resources on k8s cluster using kubectl create -f custom-resources.yaml.

kubernetes k8s api extensions customresourcedefinition ipam felix networksets tiger calico manifest yaml yml declaration operator tigera io.png

root@k8smaster01:~#
root@k8smaster01:~# kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
namespace/kube-flannel created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
root@k8smaster01:~#
root@k8smaster01:~# kubectl get nodes
NAME          STATUS   ROLES           AGE   VERSION
k8smaster01   Ready    control-plane   10m   v1.25.2
root@k8smaster01:~#
root@k8smaster01:~# kubectl create -f https://docs.projectcalico.org/manifests/tigera-operator.yaml
namespace/tigera-operator created
customresourcedefinition.apiextensions.k8s.io/bgpconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgppeers.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/blockaffinities.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/caliconodestatuses.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/clusterinformations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/felixconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworksets.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/hostendpoints.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamblocks.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamconfigs.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamhandles.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ippools.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipreservations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/kubecontrollersconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networksets.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/apiservers.operator.tigera.io created
customresourcedefinition.apiextensions.k8s.io/imagesets.operator.tigera.io created
customresourcedefinition.apiextensions.k8s.io/installations.operator.tigera.io created
customresourcedefinition.apiextensions.k8s.io/tigerastatuses.operator.tigera.io created
serviceaccount/tigera-operator created
clusterrole.rbac.authorization.k8s.io/tigera-operator created
clusterrolebinding.rbac.authorization.k8s.io/tigera-operator created
deployment.apps/tigera-operator created
root@k8smaster01:~#
root@k8smaster01:~# wget https://docs.projectcalico.org/manifests/custom-resources.yaml
--2022-09-25 18:32:49--  https://docs.projectcalico.org/manifests/custom-resources.yaml
Resolving docs.projectcalico.org (docs.projectcalico.org)... 2600:1f18:2489:8201:aeea:87a5:6524:10fd, 2600:1f18:2489:8200:a007:6646:1f31:908c, 52.203.36.44, ...
Connecting to docs.projectcalico.org (docs.projectcalico.org)|2600:1f18:2489:8201:aeea:87a5:6524:10fd|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 827 [text/yaml]
Saving to: ‘custom-resources.yaml’

custom-resources.yaml                     100%[===================================================================================>]     827  --.-KB/s    in 0s

2022-09-25 18:32:49 (40.8 MB/s) - ‘custom-resources.yaml’ saved [827/827]

root@k8smaster01:~#
root@k8smaster01:~# vim custom-resources.yaml
root@k8smaster01:~#
root@k8smaster01:~# kubectl create -f custom-resources.yaml
installation.operator.tigera.io/default created
apiserver.operator.tigera.io/default created
root@k8smaster01:~#

This is for your reference, this is the content of custom-resources.yaml and where you need to make the cidr changes.

kubernetes operator calico network ippools vxlan nodeselector apiserver tegera.io api container custom-resources networking coredns pod deployment default kube-system.png

This is the last step to verify pods in the cluster with command kubectl get pod -A. I see few networking pods are deployed successfully, everything is ready and in running status. CoreDNS pods are running. Check the nodes status with kubectl get nodes. Node is in ready status.

Kubernetes pods deployments calico apiserver calico system kube-flannel kube0system coredns typha kube controller manager proxy tigera kubectl get nod pod -A namesapces status running ready restarts control-plane cordon.png

root@k8smaster01:~#
root@k8smaster01:~# kubectl get pod -A
NAMESPACE          NAME                                       READY   STATUS    RESTARTS   AGE
calico-apiserver   calico-apiserver-7b7bb9494d-7lpgw          1/1     Running   0          8m
calico-apiserver   calico-apiserver-7b7bb9494d-ph9pj          1/1     Running   0          8m
calico-system      calico-kube-controllers-85666c5b94-8j7tz   1/1     Running   0          9m2s
calico-system      calico-node-ccsgx                          1/1     Running   0          9m3s
calico-system      calico-typha-58465c55-xz4cm                1/1     Running   0          9m3s
calico-system      csi-node-driver-pnd5j                      2/2     Running   0          9m2s
kube-flannel       kube-flannel-ds-tzk9j                      1/1     Running   0          32m
kube-system        coredns-5d5fd9958b-bm6kv                   1/1     Running   0          21m
kube-system        coredns-5d5fd9958b-mslrj                   1/1     Running   0          21m
kube-system        etcd-k8smaster01                           1/1     Running   1          42m
kube-system        kube-apiserver-k8smaster01                 1/1     Running   1          42m
kube-system        kube-controller-manager-k8smaster01        1/1     Running   0          42m
kube-system        kube-proxy-9zmjv                           1/1     Running   0          42m
kube-system        kube-scheduler-k8smaster01                 1/1     Running   1          42m
tigera-operator    tigera-operator-6675dc47f4-h2kjx           1/1     Running   0          12m
root@k8smaster01:~#
root@k8smaster01:~#
root@k8smaster01:~# kubectl get nodes
NAME          STATUS   ROLES           AGE   VERSION
k8smaster01   Ready    control-plane   43m   v1.25.2

In the next article I will join Kubernetes worker node into this master node. How to install kubernetes worker node on ubuntu Part 2

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