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](https://github.com/kubespray/kubespray-cli).

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](https://github.com/kubernetes-incubator/kubespray/blob/master/inventory/inventory.example).

You can use an
[inventory generator](https://github.com/kubernetes-incubator/kubespray/blob/master/contrib/inventory_builder/inventory.py)
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](ansible.md).

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](https://docs.ansible.com/ansible/intro_dynamic_inventory.html)).
- 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](ha.md).

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](https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/).

Accessing Kubernetes Dashboard
------------------------------

If the variable `dashboard_enabled` is set (default is true), then you can
access the Kubernetes Dashboard at the following URL:

  https://kube:_kube-password_@_host_:6443/ui/

To see the password, refer to the section above, titled *Connecting to
Kubernetes*. The host can be any kube-master or kube-node or loadbalancer
(when enabled).

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.