Bootstrap Kubernetes

the hard way & kubeadm

KaLUG 1809 @ Tady Coffee

Shawn Wang shawn111@gmail.com

k8s Components

   +------------------------------+  +--------------------+
   | master                       |  |node                |
   |   kube-apiserver             |  |   kubelet          |
   |   etcd                       |  |   kube-proxy       |
   |   kube-scheduler             |  |   Container Runtime|
   |   kube-controller-manager    |  +--------------------+
   |                              | ......................
   |   [cloud-controller-manager] | :AddOn               :
   +------------------------------+ :   DNS              :
                                    :   Dashboard        :
                                    :   monitor/log/...  :
    [drawn by textik.com]           ......................

the hard way

Bootstrap k8s the hard way on GCP. No scripts.

• Prepare cluster
  • resources / ssh
  • ca / keys
• setup masters / k8s Control Plane
  • etcd, kube-apiserver, kube-controller-manager, kube-scheduler
• setup nodes / k8s Worker Nodes
• others: config kubectl, cni, …

the easy way?

1. minikube: supported VM drivers
   • none/virtualbox/vmwarefusion/kvm/…
2. kops: supported clouds
   • AWS, GCE or DigitalOcean
   • installation, reconfiguration of your cluster, upgrading kubernetes, and eventual cluster deletion.
3. kubespray (ansible)
4. magnum (openstack/heat): container orchestration engines (COE) k8s/swarm
5. bootkube

• KataCoda: Learn Kubernetes using Interactive Browser-Based Scenarios

kubeadm

• v1.5 force on bootstrap as beginning
• provide kubeadm config / kubeadm upgrade
• kubernetes beta features
• kubeadm init –config (expr)

before kubeadm

• prepare your cluster
  • nodes (cpu/memery > 2G)
  • kubelet, runctime (docker/containerd/cri-o) ready
  • swapoff
• choice cni
  • network br_netfilter

kubeadm

• init (master)
• join (node)
• reset
• upgrade
• config
  • kubeadm config images list
  • kubeadm config images pull

Network Plugins

• Calico
• Canal
• Cilium
• Flannel
• Kube-router
• Romana
• Weave Net
• JuniperContrail/TungstenFabric

kubeadm to create HA cluster

https://kubernetes.io/docs/setup/independent/high-availability/

• masters
  • create kubeadm-config.yaml
    • apiServer
    • etcd
• worker join (similar just change master host)
  • kubeadm join ha.k8s.example.com:6443 …

k8s terms

  - Pod           - ReplicaSet
  - Service       - Deployment
  - Volume        - Stateful
  - Namespace     - DaemonSet
                  - Job