k8s: Provide an option to disable PXC operator installer

This change introduces an option to disable operator built-in PXC
installer because it may not be desirable in some cases.  In the
process, we move the check+install code into PXC#maybe_install()

Because the helm chart provides a way to install and manage the PXC
operator as a sub-chart, this change disables the operator's PXC
installer in the chart.

Change-Id: I48685f29be33ba1c40dea7f4b343bdf7573b62e8

helm/zuul-operator/templates/090-Deployment.yaml

@@ -39,6 +39,11 @@ spec:
           resources:
             {{- toYaml .Values.resources | nindent 12 }}
           {{- end }}
+          {{- if not ( index .Values "pxc-operator" "operatorManaged" ) }}
+          env:
+            - name: ZUUL_INSTALL_PXC
+              value: "0"
+          {{- end }}
       {{- with .Values.nodeSelector }}
       nodeSelector:
         {{- toYaml . | nindent 8 }}

helm/zuul-operator/values.yaml

@@ -69,3 +69,6 @@ cert-manager:
 
 pxc-operator:
   enabled: false
+
+  # cert manager should be managed by the operator
+  operatorManaged: false

zuul_operator/operator.py

@@ -14,6 +14,8 @@
 
 import asyncio
 import collections
+import distutils
+import os
 
 import kopf
 import pykube
@@ -56,6 +58,12 @@ def memoize_secrets(memo, logger):
 
 @kopf.on.startup()
 def startup(memo, logger, **kwargs):
+    logger.info("Loading operator config")
+    memo.operator_config = {
+        'install_pxc': distutils.util.strtobool(
+            os.environ.get('ZUUL_INSTALL_PXC', '1')),
+    }
+
     # Operator handlers (like this one) get a single global memo
     # object; resource handlers (like update) get a memo object for
     # that specific resource with items shallow-copied from the global
@@ -108,7 +116,8 @@ def create_fn(spec, name, namespace, logger, memo, **kwargs):
     zuul = Zuul(namespace, name, logger, spec)
     # Get DB installation started first; it's slow and has no
     # dependencies.
-    zuul.install_db()
+    zuul.install_db(install_pxc=memo.operator_config['install_pxc'])
+
     # Install Cert-Manager and request the CA cert before installing
     # ZK because the CRDs must exist.
     zuul.install_cert_manager()
@@ -142,7 +151,7 @@ def update_fn(name, namespace, logger, old, new, memo, **kwargs):
         logger.info("Database changed")
         conf_changed = True
         # redo db stuff
-        zuul.install_db()
+        zuul.install_db(install_pxc=memo.operator_config['install_pxc'])
         zuul.wait_for_db()
 
     if new.get('zookeeper') != old.get('zookeeper'):

zuul_operator/pxc.py

@@ -47,6 +47,13 @@ class PXC:
         # the operator seems like the better choice.
         utils.apply_file(self.api, 'pxc-bundle.yaml', _adopt=False)
 
+    def maybe_install(self):
+        if self.is_installed():
+            return
+
+        self.log.info("Installing PXC operator")
+        self.create_operator()
+
     def create_cluster(self, small):
         kw = {'namespace': self.namespace}
         kw['anti_affinity_key'] = small and 'none' or 'kubernetes.io/hostname'

zuul_operator/zuul.py

@@ -145,7 +145,7 @@ class Zuul:
 
     # A two-part process for PXC so that this can run while other
     # installations are happening.
-    def install_db(self):
+    def install_db(self, install_pxc=True):
         if not self.manage_db:
             self.log.info("DB is externally managed")
             return
@@ -154,9 +154,9 @@ class Zuul:
 
         self.log.info("DB is internally managed")
         self.pxc = pxc.PXC(self.api, self.namespace, self.log, self.name)
-        if not self.pxc.is_installed():
-            self.log.info("Installing PXC operator")
-            self.pxc.create_operator()
+
+        if install_pxc:
+            self.pxc.maybe_install()
 
         self.log.info("Creating PXC cluster")
         self.pxc.create_cluster(small)