c12s-kubespray/docs/getting-started.md

Getting started

The easiest way to run the deployement is to use the kubespray-cli tool. A complete documentation can be found in its github repository.

Here is a simple example on AWS:

• Create instances and generate the inventory

kubespray aws --instances 3

• Run the deployment

kubespray deploy --aws -u centos -n calico

Building your own inventory

Ansible inventory can be stored in 3 formats: YAML, JSON, or INI-like. There is an example inventory located here.

You can use an inventory generator to create or modify an Ansible inventory. Currently, it is limited in functionality and is only used for configuring a basic Kubespray cluster inventory, but it does support creating inventory file for large clusters as well. It now supports separated ETCD and Kubernetes master roles from node role if the size exceeds a certain threshold. Run python3 contrib/inventory_builder/inventory.py help help for more information.

Example inventory generator usage:

cp -r inventory my_inventory
declare -a IPS=(10.10.1.3 10.10.1.4 10.10.1.5)
CONFIG_FILE=my_inventory/inventory.cfg python3 contrib/inventory_builder/inventory.py ${IPS[@]}

Starting custom deployment

Once you have an inventory, you may want to customize deployment data vars and start the deployment:

IMPORTANT: Edit my_inventory/groups_vars/*.yaml to override data vars

ansible-playbook -i my_inventory/inventory.cfg cluster.yml -b -v \
  --private-key=~/.ssh/private_key

See more details in the ansible guide.

Adding nodes

You may want to add worker nodes to your existing cluster. This can be done by re-running the cluster.yml playbook, or you can target the bare minimum needed to get kubelet installed on the worker and talking to your masters. This is especially helpful when doing something like autoscaling your clusters.

• Add the new worker node to your inventory under kube-node (or utilize a dynamic inventory).
• Run the ansible-playbook command, substituting scale.yml for cluster.yml:

ansible-playbook -i my_inventory/inventory.cfg scale.yml -b -v \
  --private-key=~/.ssh/private_key

Connecting to Kubernetes

By default, Kubespray configures kube-master hosts with insecure access to kube-apiserver via port 8080. A kubeconfig file is not necessary in this case, because kubectl will use http://localhost:8080 to connect. The kubeconfig files generated will point to localhost (on kube-masters) and kube-node hosts will connect either to a localhost nginx proxy or to a loadbalancer if configured. More details on this process are in the HA guide.

Kubespray permits connecting to the cluster remotely on any IP of any kube-master host on port 6443 by default. However, this requires authentication. One could generate a kubeconfig based on one installed kube-master hosts (needs improvement) or connect with a username and password. By default, a user with admin rights is created, named kube. The password can be viewed after deployment by looking at the file PATH_TO_KUBESPRAY/credentials/kube_user. This contains a randomly generated password. If you wish to set your own password, just precreate/modify this file yourself.

For more information on kubeconfig and accessing a Kubernetes cluster, refer to the Kubernetes documentation.

Accessing Kubernetes Dashboard

As of kubernetes-dashboard v1.7.x:

• New login options that use apiserver auth proxying of token/basic/kubeconfig by default
• Requires RBAC in authorization_modes
• Only serves over https
• No longer available at https://first_master:6443/ui until apiserver is updated with the https proxy URL

If the variable dashboard_enabled is set (default is true), then you can access the Kubernetes Dashboard at the following URL, You will be prompted for credentials: https://first_master:6443/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/login

Or you can run 'kubectl proxy' from your local machine to access dashboard in your browser from: http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/login

It is recommended to access dashboard from behind a gateway (like Ingress Controller) that enforces an authentication token. Details and other access options here: https://github.com/kubernetes/dashboard/wiki/Accessing-Dashboard---1.7.X-and-above

Accessing Kubernetes API

The main client of Kubernetes is kubectl. It is installed on each kube-master host and can optionally be configured on your ansible host by setting kubeconfig_localhost: true in the configuration. If enabled, kubectl and admin.conf will appear in the artifacts/ directory after deployment. You can see a list of nodes by running the following commands:

cd artifacts/
./kubectl --kubeconfig admin.conf get nodes

If desired, copy kubectl to your bin dir and admin.conf to ~/.kube/config.