Pin k3s version to v1.18.6+k3s1

Closes: #656

ansible/group_vars/all/oas.yml

@@ -47,6 +47,10 @@ userbackend_admin_email: "{{ admin_email }}"
 hydra_system_secret: "{{ lookup('password', '{{ cluster_dir }}/secrets/hydra_system_secret chars=ascii_letters') }}"
 
 # Application versions
+
+k3s:
+  version: 'v1.18.6+k3s1'
+
 helm:
   # helm snap 2.15.0 and 2.15.1 broke for us
   # (https://open.greenhost.net/openappstack/openappstack/issues/338), so we

ansible/roles/setup-kubernetes/tasks/k3s.yml

@@ -10,7 +10,10 @@
 - name: Run k3s installation script
   tags:
     - k3s
-  shell: INSTALL_K3S_EXEC="server --disable traefik --disable local-storage" /tmp/k3s/install.sh
+  environment:
+    INSTALL_K3S_EXEC: "server --disable traefik --disable local-storage"
+    INSTALL_K3S_VERSION: "{{ k3s.version }}"
+  shell: /tmp/k3s/install.sh
 
 - name: Replace hostname in kubeconfig
   tags: