feat(PFP-102): Make Elasticsearch use 1 master node by default (acryldata#283)

Our dependencies chart is setup to use 3 ES nodes in 3 AZ-equivalents, but
is broadly intended for use as a test harness which often runs in single-node events.

So let's fix this and have it be single-node by default

Author: meyerkev

README.md

@@ -76,8 +76,6 @@ You should get a result similar to below.
 ```
 NAME                                               READY   STATUS      RESTARTS   AGE
 elasticsearch-master-0                             1/1     Running     0          62m
-elasticsearch-master-1                             1/1     Running     0          62m
-elasticsearch-master-2                             1/1     Running     0          62m
 prerequisites-cp-schema-registry-cf79bfccf-kvjtv   2/2     Running     1          63m
 prerequisites-kafka-0                              1/1     Running     2          62m
 prerequisites-mysql-0                              1/1     Running     1          62m
@@ -108,8 +106,6 @@ datahub-elasticsearch-setup-job-8dz6b              0/1     Completed   0
 datahub-kafka-setup-job-6blcj                      0/1     Completed   0          4m40s
 datahub-mysql-setup-job-b57kc                      0/1     Completed   0          4m7s
 elasticsearch-master-0                             1/1     Running     0          97m
-elasticsearch-master-1                             1/1     Running     0          97m
-elasticsearch-master-2                             1/1     Running     0          97m
 prerequisites-cp-schema-registry-cf79bfccf-kvjtv   2/2     Running     1          99m
 prerequisites-kafka-0                              1/1     Running     2          97m
 prerequisites-mysql-0                              1/1     Running     1          97m

charts/prerequisites/Chart.yaml

@@ -4,7 +4,7 @@ description: A Helm chart for packages that Datahub depends on
 type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
-version: 0.0.14
+version: 0.0.15
 dependencies:
   - name: elasticsearch
     version: 7.17.3

charts/prerequisites/values.yaml

@@ -2,14 +2,17 @@
 # Copy this file and update to the configuration of choice
 elasticsearch:
   enabled: true   # set this to false, if you want to provide your own ES instance.
-  replicas: 3
+
+  # If you're running in production, set this to 3 and comment out antiAffinity below
+  # Or alternatively if you're running production, bring your own ElasticSearch
+  replicas: 1
   minimumMasterNodes: 1
   # Set replicas to 1 and uncomment this to allow the instance to be scheduled on
   # a master node when deploying on a single node Minikube / Kind / etc cluster.
-  # antiAffinity: "soft"
+  antiAffinity: "soft"
 
-  # # If your running a single replica cluster add the following helm value
-  # clusterHealthCheckParams: "wait_for_status=yellow&timeout=1s"
+  # # If you are running a multi-replica cluster, comment this out
+  clusterHealthCheckParams: "wait_for_status=yellow&timeout=1s"
 
   # # Shrink default JVM heap.
   esJavaOpts: "-Xmx384m -Xms384m"