Document elasticsearch container params.

packages/server/src/integrations/tests/utils/elasticsearch.ts

@@ -13,15 +13,26 @@ export async function getDatasource(): Promise<Datasource> {
       new GenericContainer(ELASTICSEARCH_IMAGE)
         .withExposedPorts(9200)
         .withEnvironment({
+          // We need to set the discovery type to single-node to avoid the
+          // cluster waiting for other nodes to join before starting up.
           "discovery.type": "single-node",
+          // We disable security to avoid having to do any auth against the
+          // container, and to disable SSL. With SSL enabled it uses a self
+          // signed certificate that we'd have to ignore anyway.
           "xpack.security.enabled": "false",
         })
         .withWaitStrategy(
           Wait.forHttp(
+            // Single node clusters never reach status green, so we wait for
+            // yellow instead.
             "/_cluster/health?wait_for_status=yellow&timeout=10s",
             9200
           ).withStartupTimeout(60000)
         )
+        // We gave the container a tmpfs data directory. Without this, I found
+        // that the default data directory was very small and the container
+        // easily filled it up. This caused the cluster to go into a red status
+        // and stop responding to requests.
         .withTmpFs({ "/usr/share/elasticsearch/data": "rw" })
     )
   }