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 mohsen@172.16.0.10 -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