Getting Started with Kubernetes

My personal introduction to kubernetes

Nodes

Hostname	IP address
manager1	172.16.0.10
worker01	172.16.0.11
worker02	172.16.0.12
worker03	172.16.0.13

Deploy VMs

Network

• /etc/network/interfaces :

auto br0
iface br0 inet static
      address 172.16.0.1
      netmask 255.255.255.0
      network 172.16.0.0
      broadcast 172.16.0.255
      bridge_ports lo
      bridge_stp off
      bridge_maxwait 0

• SNAT:

iptables -t nat -A POSTROUTING --dst 172.16.0.0/24   -j ACCEPT
iptables -t nat -A POSTROUTING --src 172.16.0.0/24 -j MASQUERADE
iptables-save > /etc/iptables/rules.v4
systemctl enable netfilter-persistent.service

KVM

virt-install --name=manager1 \
--vcpus=2 \
--memory=4096 \
--cdrom=/home/mohsen/Downloads/ubuntu-20.04.4-live-server-amd64.iso \
--disk size=50 \
--os-variant=ubuntu20.04 \
--network bridge=br0

virt-install --name=worker01 \
--vcpus=2 \
--memory=2048 \
--cdrom=/home/mohsen/Downloads/ubuntu-20.04.4-live-server-amd64.iso \
--disk size=50 \
--os-variant=ubuntu20.04 \
--network bridge=br0

virt-install --name=worker02 \
--vcpus=2 \
--memory=2048 \
--cdrom=/home/mohsen/Downloads/ubuntu-20.04.4-live-server-amd64.iso \
--disk size=50 \
--os-variant=ubuntu20.04 \
--network bridge=br0

virt-install --name=worker03 \
--vcpus=2 \
--memory=2048 \
--cdrom=/home/mohsen/Downloads/ubuntu-20.04.4-live-server-amd64.iso \
--disk size=50 \
--os-variant=ubuntu20.04 \
--network bridge=br0

Ansible

inventory

[masters]
manager1 ansible_host=manager1.localkube

[workers]
worker01 ansible_host=worker01.localkube
worker02 ansible_host=worker02.localkube
worker03 ansible_host=worker03.localkube


[all:vars]
K8S_VERSION_APT = 1.25.9-1.1
K8S_VERSION_APT_repo = v1.25
host_key_checking = false
ansible_user=
ansible_ssh_port=22
# ansible_ssh_pass=
ansible_become=yes
ansible_ssh_private_key_file=
ansible_ssh_common_args='-o StrictHostKeyChecking=no'
CONFIG_DIR_TASKS=../../configs/
CONFIG_DIR_PLAYS=../configs/
TASKS_DIR_PLAYS=./tasks/
master_endpoint=192.168.20.17:6443
# token=
# discovery_token_ca_cert_hash=

run these:

apt list -a kubeadm
cd ./ansible/plays/
ansible-playbook -i ../inventory install_containerd.yml
ansible-playbook -i ../inventory configure_containerd.yml
ansible-playbook -i ../inventory disable_swap.yml

check macs and product_uuids: (OPTIONAL only if you are using virtual machines)

cd ../../scripts/
./check_macs.sh   
./check_product_uuids.sh

run these:

cd ../ansible/plays/
# ansible-playbook -i ../inventory set_shecan.yml # if needed
ansible-playbook -i ../inventory add_kube_apt.yml
ansible-playbook -i ../inventory install_kubectl.yml
ansible-playbook -i ../inventory install_kubelet.yml
ansible-playbook -i ../inventory install_kubeadm.yml
# ansible-playbook -i ../inventory config_file_kubeadm.yml # optional if you have a kubeadm config
ansible-playbook -i ../inventory enable_routing.yml
ansible-playbook -i ../inventory config_file_sysctl_kubernetes_cni.yml

initiate the control plane node

I'd rather to do this one manually to see the logs for now. doing these will initiate the control plane node on 172.16.0.10.

ssh [email protected] -i /home/mohsen/.ssh/github-mohsen-local-laptop -t sudo -i
kubeadm init  --apiserver-advertise-address=172.16.0.10  --pod-network-cidr=10.10.0.0/16 --kubernetes-version=1.25.9
# or # kubeadm init --config /etc/kubernetes/kubeadm-config.yaml
echo "KUBECONFIG=/etc/kubernetes/admin.conf" >> /etc/bash.bashrc
echo "cp /etc/kubernetes/admin.conf /root/.kube/config" >> /etc/bash.bashrc

you'll be prompted with the command to initiate the workers. save the master_endpoint, token and discovery_token_ca_cert_hash variables in the inventory file.

print join command:

kubeadm token create --print-join-command

before initiating the workers you need to deploy a pod network to the cluster:

install flannel/calico network pod plugin

ansible-playbook -i ../inventory install_flannel.yml

or read the file ansible/plays/install_calico.yml to get an understanding of how to install calico.

customize the calico config before kubectl create -f on it.

initiate workers

run:

ansible-playbook -i ../inventory initialize_the_workers.yml