Kubernetes Role

This ansible role installs a Kubernetes cluster.

Role Variables

The variables that can be passed to this role and a brief description about them are as follows:

# Version to install or latest
kube_version: 1.28.7
# Type of node front or wn
kube_type_of_node: front
# IP address or name of the Kube front node
kube_server: "{{ ansible_default_ipv4.address }}"
# Security Token
kube_token: "kube01.{{ lookup('password', '/tmp/tokenpass chars=ascii_lowercase,digits length=16') }}"
# Token TTL duration (0 do not expire)
kube_token_ttl: 0
# POD network cidr
kube_pod_network_cidr: 10.244.0.0/16
# Kubelet extra args
kubelet_extra_args: ''
# Flag to set HELM to be installed
kube_install_helm: true
# If true, running kubernetes etcd in ramdisk
etcd_in_RAM: true
# Deploy the Dashboard
kube_deploy_dashboard:  true
# value to pass to the kubeadm init --apiserver-advertise-address option
kube_api_server: 0.0.0.0
# A set of git repos and paths to be applied in the cluster. Following this format:
# kube_apply_repos: [{repo: "https://github.com/kubernetes-incubator/metrics-server", version: "master", path: "deploy/1.8+/"}]
kube_apply_repos: []
# Flag to set Metrics-Server to be installed
kube_install_metrics: false
# Flag to enable GPU support
enable_gpu: false
# Name (and version) of the Ansible role to include if `enable_gpu == true'
gpu_support_role: git+https://baltig.infn.it/infn-cloud/ansible-role-gpu-support,vX.Y.Z

Dependencies

ansible-role-gpu-support (if enable_gpu == true)
ansible-role-containerd (by geerlingguy)

ETCD in RAM

Requirements

The cluster must be using containerd as the container runtime and etcd must be running as a pod in the kubernetes cluster such as with a kubeadm cluster setup.

Manual setup for an existing cluster

First, download nerdctl from here and move the executable to /usr/local/bin. Then, copy the contents of the files_etcdRAM folder as follows:

files_etcdRAM/usr/lib/systemd/system/kubelet.service.d ---> /usr/lib/systemd/system/kubelet.service.d
files_etcdRAM/etc/cron.d ---> /etc/cron.d
files_etcdRAM/opt/etcdRAM/bin ---> /opt/etcdRAM/bin

Restart daemon and update crontab:

systemctl daemon-reload
crontab /etc/cron.d/etcdRAM-etcd

To mount the storage directory /var/lib/etcd as a ramdisk requires adding a single line to /etc/fstab:

tmpfs                       /var/lib/etcd        tmpfs   defaults,noatime,size=2g  0 0

Finally remove all contents from the /var/lib/etcd directory and mount the ramdisk:

rm -rf /var/lib/etcd/*
mount -a

Credits

See also the post and the original repository, where this was described.