Add option for unsupported single node with database backend. Issue #27

README.md

@@ -53,6 +53,7 @@ consistency.
 | `k3s_server_manifests_dir`       | Path for place the `k3s_server_manifests_templates`.                                | `/var/lib/rancher/k3s/server/manifests` |
 | `k3s_server_manifests_templates` | A list of Auto-Deploying Manifests Templates.                                       | []                                      |
 | `k3s_use_experimental`           | Allow the use of experimental features in k3s.                                      | `false`                                 |
+| `k3s_use_unsupported_config`     | Allow the use of unsupported configurations in k3s.                                 | `false`                                 |
 | `k3s_non_root`                   | Install k3s as non-root user. See notes below.                                      | `false`                                 |
 | `k3s_control_workers`            | Are control hosts also workers?                                                     | `true`                                  |
 | `k3s_cluster_cidr`               | Network CIDR to use for pod IPs                                                     | 10.42.0.0/16                            |
@@ -133,7 +134,8 @@ To install k3s as non root you must not use `become: true`. The intention of
 this variable is to run a single node development environment. At the time
 of release v1.0.1, rootless is still experimental.
 
-You must also ensure that you set `k3s_use_experimental` to `true`.
+You must also ensure that you set both `k3s_use_experimental`
+and `k3s_use_unsupported_config` to `true`.
 
 Additionally `k3s_install_dir` must be writable by your user.
 
@@ -169,7 +171,7 @@ Below are variables that are set against specific hosts in your inventory.
 #### Important note about `k3s_control_node` and High Availability (HA)
 
 By default only one host will be defined as a control node by Ansible, If you
-do not set a host as a control node, the role will automatically delegate
+do not set a host as a control node, this role will automatically delegate
 the first play host as a control node (master). This is not suitable for use in
 a Production workload.
 
@@ -182,6 +184,10 @@ the play hosts.
 
 See: [High Availability with an External DB](https://rancher.com/docs/k3s/latest/en/installation/ha/)
 
+It is also possible, though not supported, to run a single K3s master with a
+`k3s_datastore_endpoint` defined. As this is not a typically supported
+configuration you will need to set `k3s_use_unsupported_config` to `true`.
+
 Since K3s v1.0.0 it is possible to use DQLite as the backend database, and this
 is done by setting `k3s_dqlite_datastore` to true. As this is an experimental
 feature you will also need to set `k3s_use_experimental` to true.

defaults/main.yml

@@ -29,6 +29,9 @@ k3s_server_manifests_templates: []
 # Use experimental features in k3s?
 k3s_use_experimental: false
 
+# Allow for unsupported configurations in k3s?
+k3s_use_unsupported_config: false
+
 # Use a database or etcd cluster to enable HA. Examples below:
 # MySQL:
 #   k3s_datastore_endpoint "mysql://username:password@tcp(hostname:3306)/database-name"

tasks/build/preconfigure-k3s.yml

@@ -46,6 +46,7 @@
       @@@
       P_{{ hostvars[item].k3s_primary_control_node | default(False) }}
     create: true
+    regexp: "^{{ item }} @@@ {{ hostvars[item].ansible_host | default(hostvars[item].ansible_fqdn) }}"
   loop: "{{ play_hosts }}"
   when: hostvars[item].k3s_control_node is defined
 

tasks/validate/check-master-count.yml

@@ -9,6 +9,7 @@
     success_msg: "Control plane configuration is valid."
     fail_msg: "Control plane configuration is invalid. Please see notes about k3s_control_node and HA in README.md."
   when: k3s_controller_count | length == 1
+        and not k3s_use_unsupported_config
 
 - name: Check the conditions when multiple controllers are defined
   assert:

tasks/validate/main.yml

@@ -3,6 +3,8 @@
 - import_tasks: check-variables.yml
 - import_tasks: check-experimental-variables.yml
 - import_tasks: check-unsupported-rootless.yml
-  when: k3s_non_root is defined and k3s_non_root
+  when: k3s_non_root is defined
+        and k3s_non_root
+        and k3s_use_unsupported_config
 - import_tasks: check-master-count.yml
   when: k3s_build_cluster is defined and k3s_build_cluster