Add multilinePattern to log driver

Signed-off-by: Andre Kurait <akurait@amazon.com>

deployment/cdk/opensearch-service-migration/lib/service-stacks/migration-service-core.ts

@@ -12,7 +12,8 @@ import {
     ServiceConnectService,
     Ulimit,
     OperatingSystemFamily,
-    Volume
+    Volume,
+    AwsLogDriverMode
 } from "aws-cdk-lib/aws-ecs";
 import {DockerImageAsset} from "aws-cdk-lib/aws-ecr-assets";
 import {RemovalPolicy, Stack} from "aws-cdk-lib";
@@ -130,7 +131,13 @@ export class MigrationServiceCore extends Stack {
             portMappings: props.portMappings,
             logging: LogDrivers.awsLogs({
                 streamPrefix: `${props.serviceName}-logs`,
-                logGroup: serviceLogGroup
+                logGroup: serviceLogGroup,
+                // E.g. "[INFO ] 2024-12-31 23:59:59,99999999"
+                // and  "[ERROR] 2024-12-31 23:59:59,999"
+                // and  "2024-12-31 23:59:59"
+                multilinePattern: "^(\\[[A-Z ]{1,5}\\] )?\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}(,\\d{2,8})?",
+                // Log appenders are non-blocking so defer async behavior to them
+                mode: AwsLogDriverMode.BLOCKING,
             }),
             ulimits: props.ulimits
         });
@@ -169,7 +176,9 @@ export class MigrationServiceCore extends Stack {
                     logGroup: serviceLogGroup
                 })
             },
-            cloudMapOptions: cloudMapOptions
+            cloudMapOptions: cloudMapOptions,
+            minHealthyPercent: 0,
+            maxHealthyPercent: 200
         });
 
         if (props.serviceDiscoveryEnabled) {