thuydang/k8s-cluster-ansible

Quick k8s cluster with Flannel pod network

k8s-controller-node

Cloud lab

These playbooks are run on a controller node to install k8s on a baremetal/VM cluster based on this post https://linuxconfig.org/how-to-install-kubernetes-on-ubuntu-20-04-focal-fossa-linux. After initialized with playbook, all hosts will have admin user and PK authentication.

hosts: user: admin nopw

Keys

Change permission for key fiels in the keys folder. chmod 700 .ssh chmod 600 .ssh/authorized_keys chmod 600 keys/id*

Usage

These playbooks are applied to Ubuntu 20.04 baremetals or VMs.

Host group

Default host group is k8s-all. Set the --extra-vars "variable_hosts=newtargets" in ansible-playbook command to override it.

Update masters and workers nodes IP, root password in inventory file ./ansible/hosts.

Step 0 - Setup baremetal nodes

Make sure br_netfilter kernel module is loaded. Auto loaded in playbook.

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

1. Run playbook for user and keys:

   ansible-playbook --extra-vars "variable_hosts=k8s-all" ./playbooks/0_setup_baremetal.yml

2. Set hostname

   sudo hostnamectl set-hostname host_name sudo vim /etc/hosts

3. Disable UFW, Ubuntu firewall

   systemctl stop ufw systemctl disable ufw

4. Optional: Firewall rules. Run firewall.sh, check default net dev

Step 1 - Setup container backend

 ansible-playbook --extra-vars "variable_hosts=k8s-all" ./playbooks/1_1_setup_container.yml

Step 2 - Setup k8s

 ansible-playbook --extra-vars "variable_hosts=k8s-all" ./playbooks/1_2_kube_dependencies.yml
 ansible-playbook --extra-vars "variable_hosts=k8s-all" ./playbooks/2_master.yml
 ansible-playbook --extra-vars "variable_hosts=k8s-all" ./playbooks/3_workers.yml

Step 3 - Test the setup

 ssh admin@master -i ../keys/id_rsa
 kubectl get nodes -o wide

Tips

Rerun the playbook from tasks: use --start-at-task "name_string" to skip the preceeding tasks.

Security

• https://gist.github.com/thuydang/68904d3b7699b000e3b0
• https://stackoverflow.com/questions/39293441/needed-ports-for-kubernetes-cluster

History

20220523: installed k8s using playbooks.