Implement Readiness Probe

operator/operator.yaml

@@ -16,6 +16,7 @@ tasks:
       - cassandra-env-sh.yaml
       - jvm-options.yaml
       - stateful-set.yaml
+      - cassandra-healthcheck-sh.yaml
 
 plans:
   deploy:

operator/params.yaml

@@ -701,3 +701,15 @@ JVM_OPT_MAX_GC_PAUSE_MILLIS:
 JVM_OPT_G1R_SET_UPDATING_PAUSE_TIME_PERCENT:
   description: "Have the JVM do less remembered set work during STW, instead preferring concurrent GC. Reduces p99.9 latency."
   default:
+
+READINESS_CHECK_INITIAL_DELAY:
+  description: "An amount of time in seconds to wait before starting the readiness check attempts."
+  default: "0"
+
+READINESS_CHECK_PERIOD:
+  description: "The period in seconds to wait after the last readiness check has completed to start the next check."
+  default: "5"
+
+READINESS_CHECK_TIMEOUT:
+  description: "An amount of time in seconds to wait for a readiness check to succeed."
+  default: "60"

operator/templates/cassandra-healthcheck-sh.yaml

@@ -0,0 +1,7 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cassandra-healthcheck-sh
+data:
+  cassandra-healthcheck.sh: |
+    echo "Hello!"

operator/templates/stateful-set.yaml

@@ -62,6 +62,13 @@ spec:
                 command:
                   - nodetool
                   - drain
+          readinessProbe:
+            exec:
+              command:
+                - nodetool status -p {{ .Params.JMX_PORT }}
+            initialDelaySeconds: {{ .Params.READINESS_CHECK_INITIAL_DELAY }}
+            periodSeconds: {{ .Params.READINESS_CHECK_PERIOD }}
+            timeoutSeconds: {{ .Params.READINESS_CHECK_TIMEOUT }}
           command:
             - cassandra
             - -f
@@ -133,6 +140,9 @@ spec:
             - name: jvm-options
               mountPath: /etc/cassandra/jvm.options
               subPath: jvm.options
+            - name: cassandra-healthcheck-sh
+              mountPath: /etc/cassandra/cassandra-healthcheck.sh
+              subPath: cassandra-healthcheck.sh
       volumes:
         # Overwriting /etc/cassandra/ available in the Docker image.
         - name: etc-cassandra
@@ -146,6 +156,9 @@ spec:
         - name: jvm-options
           configMap:
             name: {{ .Name }}-jvm-options
+        - name: cassandra-healthcheck-sh
+          configMap:
+            name: {{ .Name }}-cassandra-healthcheck-sh
   volumeClaimTemplates:
     - metadata:
         name: var-lib-cassandra

templates/operator/operator.yaml.template

@@ -16,6 +16,7 @@ tasks:
       - cassandra-env-sh.yaml
       - jvm-options.yaml
       - stateful-set.yaml
+      - cassandra-healthcheck-sh.yaml
 
 plans:
   deploy: