add scale.yml to do minimum needed for a node bootstrap

docs/getting-started.md

@@ -55,3 +55,15 @@ ansible-playbook -i my_inventory/inventory.cfg cluster.yml -b -v \
 ```
 
 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
+```

scale.yml

@@ -0,0 +1,34 @@
+---
+
+##Bootstrap any new workers
+- hosts: kube-node
+  any_errors_fatal: "{{ any_errors_fatal | default(true) }}"
+  gather_facts: false
+  vars:
+    ansible_ssh_pipelining: false
+  roles:
+    - { role: kargo-defaults}
+    - { role: bootstrap-os, tags: bootstrap-os}
+
+##We still have to gather facts about our masters and etcd nodes
+- hosts: k8s-cluster:etcd:calico-rr
+  any_errors_fatal: "{{ any_errors_fatal | default(true) }}"
+  vars:
+    ansible_ssh_pipelining: true
+  gather_facts: true
+
+##Target only workers to get kubelet installed and checking in on any new nodes
+- hosts: kube-node
+  any_errors_fatal: "{{ any_errors_fatal | default(true) }}"
+  roles:
+    - { role: kargo-defaults}
+    - { role: kernel-upgrade, tags: kernel-upgrade, when: kernel_upgrade is defined and kernel_upgrade }
+    - { role: kubernetes/preinstall, tags: preinstall }
+    - { role: docker, tags: docker }
+    - role: rkt
+      tags: rkt
+      when: "'rkt' in [etcd_deployment_type, kubelet_deployment_type, vault_deployment_type]"
+    - { role: etcd, tags: etcd, etcd_cluster_setup: false }
+    - { role: vault, tags: vault, when: "cert_management == 'vault'"}
+    - { role: kubernetes/node, tags: node }
+    - { role: network_plugin, tags: network }