Test single-node cluster (techno-tim#78)

* Molecule: Derive overrides.yml location from scenario dir

# Conflicts:
#	molecule/default/molecule.yml
#	molecule/ipv6/molecule.yml

* Molecule: Add single_node scenario

* Fix get_nodes test for the case of empty groups

.github/workflows/test.yml

@@ -15,6 +15,8 @@ jobs:
  matrix:
  scenario:
  - default
+ - single_node
+ fail-fast: false
  env:
  PYTHON_VERSION: "3.10"
 

molecule/README.md

@@ -8,6 +8,8 @@ We have these scenarios:
 
 - **default**:
  A 3 control + 2 worker node cluster based very closely on the [sample inventory](../inventory/sample/).
+- **single_node**:
+ Very similar to the default scenario, but uses only a single node for all cluster functionality.
 
 ## How to execute
 
@@ -29,7 +31,7 @@ Furthermore, the test cluster uses the `192.168.30.0/24` subnet which is [not se
 To set the subnet up for use with VirtualBox, please make sure that `/etc/vbox/networks.conf` exists and that it contains this line:
 
 ```
-* 192.168.30.0/24`
+* 192.168.30.0/24
 ```
 
 ### Install Python dependencies

molecule/default/molecule.yml

@@ -53,8 +53,6 @@ provisioner:
  inventory:
  links:
  group_vars: ../../inventory/sample/group_vars
- env:
- OVERRIDES_FILE: ../default/overrides.yml
 scenario:
  test_sequence:
  - dependency

molecule/resources/converge.yml

@@ -1,7 +1,7 @@
 ---
 - name: Apply overrides
  ansible.builtin.import_playbook: >-
- {{ lookup("ansible.builtin.env", "OVERRIDES_FILE") }}
+ {{ lookup("ansible.builtin.env", "MOLECULE_SCENARIO_DIRECTORY") }}/overrides.yml
 
 - name: Converge
  ansible.builtin.import_playbook: ../../site.yml

molecule/resources/reset.yml

@@ -1,7 +1,7 @@
 ---
 - name: Apply overrides
  ansible.builtin.import_playbook: >-
- {{ lookup("ansible.builtin.env", "OVERRIDES_FILE") }}
+ {{ lookup("ansible.builtin.env", "MOLECULE_SCENARIO_DIRECTORY") }}/overrides.yml
 
 - name: Reset
  ansible.builtin.import_playbook: ../../reset.yml

molecule/resources/verify/from_outside/tasks/test/get-nodes.yml

@@ -12,6 +12,13 @@
  fail_msg: "Expected nodes {{ expected_nodes }}, but found nodes {{ found_nodes }}"
  vars:
  found_nodes: >-
- {{ cluster_nodes | json_query('resources[*].metadata.name') | unique }}
- expected_nodes: >-
- {{ (groups['master'] + groups['node']) | unique }}
+ {{ cluster_nodes | json_query('resources[*].metadata.name') | unique | sort }}
+ expected_nodes: |-
+ {{
+ (
+ ( groups['master'] | default([]) ) +
+ ( groups['node'] | default([]) )
+ )
+ | unique
+ | sort
+ }}

molecule/single_node/molecule.yml

@@ -0,0 +1,48 @@
+---
+dependency:
+ name: galaxy
+driver:
+ name: vagrant
+platforms:
+ - name: control1
+ box: generic/ubuntu2204
+ memory: 4096
+ cpus: 4
+ config_options:
+ # We currently can not use public-key based authentication on Ubuntu 22.04,
+ # see: https://github.com/chef/bento/issues/1405
+ ssh.username: "vagrant"
+ ssh.password: "vagrant"
+ groups:
+ - k3s_cluster
+ - master
+ interfaces:
+ - network_name: private_network
+ ip: 192.168.30.50
+provisioner:
+ name: ansible
+ playbooks:
+ converge: ../resources/converge.yml
+ side_effect: ../resources/reset.yml
+ verify: ../resources/verify.yml
+ inventory:
+ links:
+ group_vars: ../../inventory/sample/group_vars
+scenario:
+ test_sequence:
+ - dependency
+ - lint
+ - cleanup
+ - destroy
+ - syntax
+ - create
+ - prepare
+ - converge
+ # idempotence is not possible with the playbook in its current form.
+ - verify
+ # We are repurposing side_effect here to test the reset playbook.
+ # This is why we do not run it before verify (which tests the cluster),
+ # but after the verify step.
+ - side_effect
+ - cleanup
+ - destroy

molecule/single_node/overrides.yml

@@ -0,0 +1,15 @@
+---
+- name: Apply overrides
+ hosts: all
+ tasks:
+ - name: Override host variables
+ ansible.builtin.set_fact:
+ # See: https://github.com/flannel-io/flannel/blob/67d603aaf45ef80f5dd39f43714fc5e6f8a637eb/Documentation/troubleshooting.md#Vagrant # noqa yaml[line-length]
+ flannel_iface: eth1
+
+ # The test VMs might be a bit slow, so we give them more time to join the cluster:
+ retry_count: 45
+
+ # Make sure that our IP ranges do not collide with those of the default scenario
+ apiserver_endpoint: "192.168.30.223"
+ metal_lb_ip_range: "192.168.30.91-192.168.30.99"