single-machine: downscale assert fix (#1216)

* single-machine: disabling downscale assert (fix)

* docs/CLUSTER: markdown fix + adding "any" provider example with haproxy

* updating changelog for v0.6.1

CHANGELOG-0.6.md

@@ -7,6 +7,7 @@
 - [#1154](https://github.com/epiphany-platform/epiphany/issues/1154) - Node exporter is not installed on logging vms
 - [#1135](https://github.com/epiphany-platform/epiphany/issues/1135) - 2ndquadrant yum repos remain enabled on repository host after teardown
 - [#1169](https://github.com/epiphany-platform/epiphany/issues/1169) - Task 'Get token from master' fails on-prem when calico plugin is used
+- [#1182](https://github.com/epiphany-platform/epiphany/issues/1182) - Re-run single machine installation may fail
 
 ### Updates
 

core/src/epicli/cli/engine/ApplyEngine.py

@@ -93,22 +93,29 @@ def validate(self):
         return 0
 
     def assert_no_master_downscale(self):
+        components = self.cluster_model.specification.components
+
+        # Skip downscale assertion for single machine clusters
+        if ('single_machine' in components) and (int(components['single_machine']['count']) > 0):
+            return
+
         cluster_name = self.cluster_model.specification.name
         inventory_path = get_inventory_path(cluster_name)
 
-        if os.path.exists(inventory_path):
+        if os.path.isfile(inventory_path):
             existing_inventory = InventoryManager(loader=DataLoader(), sources=inventory_path)
 
-            sanity_check = all([
+            both_present = all([
                 'kubernetes_master' in existing_inventory.list_groups(),
-                'kubernetes_master' in self.cluster_model.specification.components,
+                'kubernetes_master' in components,
             ])
-            if sanity_check:
+
+            if both_present:
                 prev_master_count = len(existing_inventory.list_hosts(pattern='kubernetes_master'))
-                next_master_count = int(self.cluster_model.specification.components['kubernetes_master']['count'])
+                next_master_count = int(components['kubernetes_master']['count'])
 
                 if prev_master_count > next_master_count:
-                    raise Exception("ControlPlane downscale is not supported yet. Please revert your kubernetes_master count to previous value or increase it to scale up kubernetes.")
+                    raise Exception("ControlPlane downscale is not supported yet. Please revert your 'kubernetes_master' count to previous value or increase it to scale up kubernetes.")
 
     def apply(self):
         self.process_input_docs()

docs/home/howto/CLUSTER.md

@@ -358,6 +358,84 @@ specification:
   - name: auth-service
     enabled: yes # set to yest to enable authentication service
     ... # add other authentication service configuration as needed
+```
+
+To create a single machine cluster using the "any" provider (with extra load\_balancer config included) use the following template below:
+
+```yaml
+kind: epiphany-cluster
+title: "Epiphany cluster Config"
+provider: any
+name: single
+specification:
+  name: single
+  admin_user:
+    name: ubuntu
+    key_path: /shared/id_rsa
+  components:
+    kubernetes_master:
+      count: 0
+    kubernetes_node:
+      count: 0
+    logging:
+      count: 0
+    monitoring:
+      count: 0
+    kafka:
+      count: 0
+    postgresql:
+      count: 0
+    load_balancer:
+      count: 1
+      configuration: default
+      machines: [single-machine]
+    rabbitmq:
+      count: 0
+    single_machine:
+      count: 1
+      configuration: default
+      machines: [single-machine]
+---
+kind: configuration/haproxy
+title: HAProxy
+provider: any
+name: default
+specification:
+  version: '1.8'
+  service_port: 30001
+  logs_max_days: 60
+  self_signed_certificate_name: self-signed-fullchain.pem
+  self_signed_private_key_name: self-signed-privkey.pem
+  self_signed_concatenated_cert_name: self-signed-test.tld.pem
+  haproxy_log_path: /var/log/haproxy.log
+  stats:
+    enable: true
+    bind_address: 127.0.0.1:9000
+    uri: /haproxy?stats
+    user: operations
+    password: your-haproxy-stats-pwd
+  frontend:
+  - name: https_front
+    port: 443
+    https: yes
+    backend:
+    - http_back1
+  backend: # example backend config below
+  - name: http_back1
+    server_groups:
+    - kubernetes_master
+      # servers: # Definition for server to that hosts the application.
+      # - name: "node1"
+      #   address: "epiphany-vm1.domain.com"
+    port: 30104
+---
+kind: infrastructure/machine
+provider: any
+name: single-machine
+specification:
+  hostname: x1a1
+  ip: 10.20.2.10
+```
 
 ## How to create custom cluster components