feat(ecs): add ability to set DNS servers and ephemeral storage size

- --container-dns-servers can now be used to set the dnsServers setting
  for the Artillery container
- --ephemeral-storage can now be used to set the amount of ephemeral storage for the worker task

packages/artillery/lib/cmds/run-fargate.js

@@ -129,6 +129,16 @@ RunCommand.flags = {
     description:
       'JSON to customize launch configuration of ECS/Fargate tasks (see https://www.artillery.io/docs/reference/cli/run-fargate#using---launch-config)'
   }),
+  'container-dns-servers': Flags.string({
+    description:
+      'Comma-separated list of DNS servers for Artillery container. Maps to dnsServers parameter in ECS container definition'
+  }),
+  'task-ephemeral-storage': Flags.string({
+    description:
+      'Ephemeral storage in GiB for the worker task. Maps to ephemeralStorage parameter in ECS container definition. Fargate-only.',
+    type: 'integer',
+  }),
+
   'subnet-ids': Flags.string({
     description:
       'Comma-separated list of AWS VPC subnet IDs to launch Fargate tasks in'

packages/artillery/lib/platform/aws-ecs/legacy/run-cluster.js

@@ -1203,6 +1203,10 @@ async function ensureTaskExists(context) {
       }
     };
 
+    if (context.cliOptions.containerDnsServers) {
+      artilleryContainerDefinition.dnsServers = context.cliOptions.containerDnsServers.split(',');
+    }
+
     let taskDefinition = {
       family: context.taskName,
       containerDefinitions: [artilleryContainerDefinition],
@@ -1495,6 +1499,12 @@ async function generateTaskOverrides(context) {
     overrides.taskRoleArn = context.customRoleArn;
   }
 
+  if (context.cliOptions.taskEphemeralStorage) {
+    overrides.ephemeralStorage = {
+      sizeInGiB: context.cliOptions.taskEphemeralStorage
+    };
+  }
+
   overrides.containerOverrides[0].environment.push({
     name: 'USE_V2',
     value: 'true'