How to create Kubernetes Cluster fast using Kubespray?

Step-1: Create the nodes (skip if you already have a bunch of VMs ready)

Create the controller and worker nodes using vagrant, virtual box, or any other tool. I have created one controller node and one worker node in this example. I am not covering how to create a virtual machine here.

Step-2: Create an ansible controller node(could be a virtual machine or any existing node with ansible)

Create an additional virtual machine that we will use to communicate to the controller and worker nodes. 

Step-3: Install git and pip3 

sudo apt update && sudo apt-get -y install python3-pip git -y

Step-4: Clone the git repo

techie@ansible-controller:~$ git clone https://github.com/kubernetes-sigs/kubespray.git
Cloning into 'kubespray'...
remote: Enumerating objects: 59019, done.
remote: Counting objects: 100% (770/770), done.
remote: Compressing objects: 100% (444/444), done.
remote: Total 59019 (delta 282), reused 656 (delta 237), pack-reused 58249
Receiving objects: 100% (59019/59019), 17.39 MiB | 16.49 MiB/s, done.
Resolving deltas: 100% (33160/33160), done.
techie@ansible-controller:~$

Step-5: Install the requirements for kubespray

techie@ansible-controller:~$ cd kubespray/
techie@ansible-controller:~/kubespray$ sudo pip3 install -r requirements.txt

Step-6: Make a list of the IP address of the nodes

 Here store all the note IPs in the bash array called IPS. Here, 1st IP is the master IP and 2nd IP is the worker IP. Here , We also copy sample inventory data to a new directory called mycluster. 

techie@ansible-controller:~/kubespray$ declare -a IPS=(192.168.122.51 192.168.122.100 192.168.122.250 192.168.122.150 192.168.122.139 192.168.122.98)
techie@ansible-controller:~/kubespray$ cp -rfp inventory/sample inventory/mycluster
techie@ansible-controller:~/kubespray$ echo ${IPS[@]}
192.168.122.51 192.168.122.100 192.168.122.250 192.168.122.150 192.168.122.139 192.168.122.98
techie@ansible-controller:~/kubespray$

Step-7: Built the inventory file using the list IP address

Here Kubespray would build an inventory file for us based on the number of nodes we provided. In the following steps, we supplied the list of nodes via ${IPS[@]}.  However, this does not mean that we cannot design our cluster. We can and should design the cluster by modifying the inventory file in the next step.

techie@ansible-controller:~/kubespray$ CONFIG_FILE=inventory/mycluster/hosts.yaml python3 contrib/inventory_builder/inventory.py ${IPS[@]}
DEBUG: Adding group all
DEBUG: Adding group kube_control_plane
DEBUG: Adding group kube_node
DEBUG: Adding group etcd
DEBUG: Adding group k8s_cluster
DEBUG: Adding group calico_rr
DEBUG: adding host node1 to group all
DEBUG: adding host node2 to group all
DEBUG: adding host node3 to group all
DEBUG: adding host node4 to group all
DEBUG: adding host node5 to group all
DEBUG: adding host node6 to group all
DEBUG: adding host node1 to group etcd
DEBUG: adding host node2 to group etcd
DEBUG: adding host node3 to group etcd
DEBUG: adding host node1 to group kube_control_plane
DEBUG: adding host node2 to group kube_control_plane
DEBUG: adding host node1 to group kube_node
DEBUG: adding host node2 to group kube_node
DEBUG: adding host node3 to group kube_node
DEBUG: adding host node4 to group kube_node
DEBUG: adding host node5 to group kube_node
DEBUG: adding host node6 to group kube_node

Step-8: Vizualize the automatically created inventory file

Check the inventory file and note that all the nodes are added to the inventory file. A few are assigned to the “kube_control_plane” host group, and others are assigned to the “kube_node” group. This essentially means that The nodes belonging to “kube_control_plane” would be controller nodes, while the nodes assigned to “kube_node” would be worker nodes. 

cat  inventory/mycluster/hosts.yaml
all:
  hosts:
    node1:
      ansible_host: 192.168.122.51
      ip: 192.168.122.51
      access_ip: 192.168.122.51
    node2:
      ansible_host: 192.168.122.100
      ip: 192.168.122.100
      access_ip: 192.168.122.100
    node3:
      ansible_host: 192.168.122.250
      ip: 192.168.122.250
      access_ip: 192.168.122.250
    node4:
      ansible_host: 192.168.122.150
      ip: 192.168.122.150
      access_ip: 192.168.122.150
    node5:
      ansible_host: 192.168.122.139
      ip: 192.168.122.139
      access_ip: 192.168.122.139
    node6:
      ansible_host: 192.168.122.98
      ip: 192.168.122.98
      access_ip: 192.168.122.98
  children:
    kube_control_plane:
      hosts:
        node1:
        node2:
    kube_node:
      hosts:
        node1:
        node2:
        node3:
        node4:
        node5:
        node6:
    etcd:
      hosts:
        node1:
        node2:
        node3:
    k8s_cluster:
      children:
        kube_control_plane:
        kube_node:
    calico_rr:
      hosts: {}