ansible-k8s

An Ansible role to deploy Kubernetes (k8s) on a cluster of debian based systems.

Table of Contents

• Side notes
• Role Variables
• Dependencies
• Use the Vagrant Playground
  • Requirements
  • How to use it
• Additional Info
  • Reset k8s cluster
  • Get a list of pods and information on them
• License
• Author Information

Side notes

• By default coreos/flannel is used for the pod networking.
• but this role is as well compatible to weaveworks/weave.

Role Variables

defaults/main.yml

Dependencies

None

Use the Vagrant Playground

Included in the Vagrant folder is a testing environment with 3 nodes.

• node0 - K8s Cluster Master (192.168.250.10)
• node1 - K8s Cluster Member (192.168.250.11)
• node2 - K8s Cluster Member (192.168.250.12)

The folder includes an examplary Ansible playbook.

Requirements

Packages installed on your system:

• Ansible
• Vagrant
• Virtualbox

How to use it

cd into that directory and install additional required Ansible roles:

cd Vagrant/
ansible-galaxy install -r requirements.yml

Now you can easily spin this up for learning purposes:

vagrant up

Once the environment spins up you will see the following:

TASK [ansible-k8s : cluster_summary | Displaying Cluster Nodes] ****************
skipping: [node1]
ok: [node0] => {
    "_k8s_cluster_nodes['stdout_lines']": [
        "NAME      STATUS     AGE       VERSION",
        "node0     Ready      1m        v1.14.1",
        "node1     NotReady   4s        v1.14.1",
        "node2     NotReady   6s        v1.14.1"
    ],
    "changed": false
}
skipping: [node2]

Do not worry about the above as the additional nodes did not completely join the cluster before the provisioning completed. You can quickly validate that the additional nodes are up and Ready by running:

ansible-playbook -i hosts playbook.yml --tags k8s_cluster_nodes

The above NotReady should no longer be an issue as we now wait for all nodes in the cluster to become Ready. However, there may be an instance where this may not work as expected.

TASK [ansible-k8s : cluster_summary | Displaying Cluster Nodes] ******************************************************************************************************************
skipping: [node1]
skipping: [node2]
ok: [node0] => {
    "_k8s_cluster_nodes['stdout_lines']": [
        "NAME      STATUS    ROLES     AGE       VERSION",
        "node0     Ready     master    3m        v1.14.3",
        "node1     Ready     <none>    2m        v1.14.3",
        "node2     Ready     <none>    2m        v1.14.3"
    ]
}

Once the cluster is up ssh to node0 and begin playing:

vagrant ssh node0

When you are all done using the environment easily tear it down:

./cleanup.sh

==> node2: Forcing shutdown of VM...
==> node2: Destroying VM and associated drives...
==> node1: Forcing shutdown of VM...
==> node1: Destroying VM and associated drives...
==> node0: Forcing shutdown of VM...
==> node0: Destroying VM and associated drives...

Additional Info

Reset k8s cluster

ansible-playbook -i hosts playbook.yml --tags k8s_reset -e "k8s_reset_cluster=true"

Get a list of pods and information on them

ansible-playbook -i hosts playbook.yml --tags k8s_pods

{
        "containers": [
            {
                "hostIP": "192.168.250.10",
                "image": "gcr.io/google_containers/etcd-amd64:3.1.10",
                "name": "etcd",
                "nodeName": "node0",
                "phase": "Running",
                "podIP": "192.168.250.10",
                "resources": {}
            },
            {
                "hostIP": "192.168.250.10",
                "image": "gcr.io/google_containers/kube-apiserver-amd64:v1.14.3",
                "name": "kube-apiserver",
                "nodeName": "node0",
                "phase": "Running",
                "podIP": "192.168.250.10",
                "resources": {
                    "requests": {
                        "cpu": "250m"
                    }
                }
            },
            /* ... */
        ]
    }
}

License

MIT

Author Information

• Larry Smith Jr.
• Menno van Rahden