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Clean-up references to inventory_builder in docs

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Max Gautier
2024-11-26 14:54:12 +01:00
parent 56e41f0647
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5 changed files with 32 additions and 116 deletions
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docs/ansible/ansible.md
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@@ -34,91 +34,23 @@ Based on the table below and the available python version for your ansible host
|-----------------|----------------|
| >= 2.16.4 | 3.10-3.12 |
## Inventory
The inventory is composed of 3 groups:
## Customize Ansible vars
* **kube_node** : list of kubernetes nodes where the pods will run.
* **kube_control_plane** : list of servers where kubernetes control plane components (apiserver, scheduler, controller) will run.
* **etcd**: list of servers to compose the etcd server. You should have at least 3 servers for failover purpose.
When _kube_node_ contains _etcd_, you define your etcd cluster to be as well schedulable for Kubernetes workloads.
If you want it a standalone, make sure those groups do not intersect.
If you want the server to act both as control-plane and node, the server must be defined
on both groups _kube_control_plane_ and _kube_node_. If you want a standalone and
unschedulable control plane, the server must be defined only in the _kube_control_plane_ and
not _kube_node_.
There are also two special groups:
* **calico_rr** : explained for [advanced Calico networking cases](/docs/CNI/calico.md)
* **bastion** : configure a bastion host if your nodes are not directly reachable
Lastly, the **k8s_cluster** is dynamically defined as the union of **kube_node**, **kube_control_plane** and **calico_rr**.
This is used internally and for the purpose of defining whole cluster variables (`<inventory>/group_vars/k8s_cluster/*.yml`)
Below is a complete inventory example:
```ini
## Configure 'ip' variable to bind kubernetes services on a
## different ip than the default iface
node1 ansible_host=95.54.0.12 ip=10.3.0.1
node2 ansible_host=95.54.0.13 ip=10.3.0.2
node3 ansible_host=95.54.0.14 ip=10.3.0.3
node4 ansible_host=95.54.0.15 ip=10.3.0.4
node5 ansible_host=95.54.0.16 ip=10.3.0.5
node6 ansible_host=95.54.0.17 ip=10.3.0.6
[kube_control_plane]
node1
node2
[etcd]
node1
node2
node3
[kube_node]
node2
node3
node4
node5
node6
```
## Group vars and overriding variables precedence
The group variables to control main deployment options are located in the directory ``inventory/sample/group_vars``.
Optional variables are located in the `inventory/sample/group_vars/all.yml`.
Mandatory variables that are common for at least one role (or a node group) can be found in the
`inventory/sample/group_vars/k8s_cluster.yml`.
There are also role vars for docker, kubernetes preinstall and control plane roles.
According to the [ansible docs](https://docs.ansible.com/ansible/latest/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable),
those cannot be overridden from the group vars. In order to override, one should use
the `-e` runtime flags (most simple way) or other layers described in the docs.
Kubespray uses only a few layers to override things (or expect them to
be overridden for roles):
Kubespray expects users to use one of the following variables sources for settings and customization:
| Layer | Comment |
|----------------------------------------|------------------------------------------------------------------------------|
| **role defaults** | provides best UX to override things for Kubespray deployments |
| inventory vars | Unused |
| **inventory group_vars** | Expects users to use ``all.yml``,``k8s_cluster.yml`` etc. to override things |
| inventory host_vars | Unused |
| playbook group_vars | Unused |
| playbook host_vars | Unused |
| **host facts** | Kubespray overrides for internal roles' logic, like state flags |
| play vars | Unused |
| play vars_prompt | Unused |
| play vars_files | Unused |
| registered vars | Unused |
| set_facts | Kubespray overrides those, for some places |
| **role and include vars** | Provides bad UX to override things! Use extra vars to enforce |
| block vars (only for tasks in block) | Kubespray overrides for internal roles' logic |
| task vars (only for the task) | Unused for roles, but only for helper scripts |
| inventory vars | |
| - **inventory group_vars** | most used |
| - inventory host_vars | host specifc vars overrides, group_vars is usually more practical |
| **extra vars** (always win precedence) | override with ``ansible-playbook -e @foo.yml`` |
[!IMPORTANT]
Extra vars are best used to override kubespray internal variables, for instances, roles/vars/.
Those vars are usually **not expected** (by Kubespray developpers) to be modified by end users, and not part of Kubespray
interface. Thus they can change, disappear, or break stuff unexpectedly.
## Ansible tags
The following tags are defined in playbooks: