diff --git a/plugins/discovery-ec2/README.md b/plugins/discovery-ec2/README.md
new file mode 100644
index 0000000000000..6daeb6305b988
--- /dev/null
+++ b/plugins/discovery-ec2/README.md
@@ -0,0 +1,94 @@
+# discovery-ec2
+
+The discovery-ec2 plugin allows OpenSearch to find the master-eligible nodes in a cluster running on AWS EC2 by querying the AWS Instance Metadata Service ([IMDS](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html)) API for the addresses of the EC2 instances running these nodes.
+
+This is typically configured as follows in `opensearch.yml`.
+
+```yml
+cluster.initial_cluster_manager_nodes: ["seed"]
+discovery.seed_providers: ec2
+discovery.ec2.tag.role: my-cluster-manager
+```
+
+The implementation in the discovery-ec2 plugin queries for instances of a given type (e.g. private or public IP), with a tag, or running in a specific availability zone.
+
+## Testing
+
+### Unit and Integration Tests
+
+```
+./gradlew :plugins:discovery-ec2:check
+```
+
+### Manual Testing
+
+The following instructions manually exercise the plugin.
+
+Setup a 5-node (Ubuntu) cluster on EC2, with 3 of them tagged with `role: my-cluster-manager`, and a custom TCP rule to expose ports 9200 to 9300 to allow TCP traffic. Default EC2 configuration only allows SSH TCP traffic and hence only exposes port 22.
+
+Set the following properties.
+
+- `network.host`: Set this to the IP of the eth0 network adapter, can be fetched by `ipconfig` or by running `hostname -I` on Linux hosts.
+- `discovery.seed_hosts`: List of all nodes in the cluster.
+- `cluster.initial_cluster_manager_nodes`: List of all initial cluster manager nodes.
+- `discovery.seed_providers`: Set this to `ec2` for EC2 IMDS based discovery.
+- `discovery.ec2.tag.role: my-cluster-manager`: Filter out only those nodes with value `my-cluster-manager` for the `role` tag.
+- `discovery.ec2.region`: Optionally set to your region, e.g. `us-east-1`, by default the plugin uses the region of the current EC2 instance.
+
+While sending the request to IMDS, specified discovery settings for finding master-eligible nodes are being set. You will see the following in the logs.
+
+```
+[2023-05-31T15:22:39,274][DEBUG][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] using host_type [private_ip], tags [{role=[my-cluster-manager]}], groups [[]] with any_group [true], availability_zones [[]]
+```
+
+The nodes getting added as eligible masters are ones with the role tag set to `my-cluster-manager`.
+
+```
+[2023-05-31T15:23:03,676][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] finding seed nodes...
+[2023-05-31T15:23:03,677][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] adding i-01fa1736e8566c693, address 172.31.73.184, transport_address 172.31.73.184:9300
+[2023-05-31T15:23:03,677][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] adding i-03d70a4521045cc3b, address 172.31.74.169, transport_address 172.31.74.169:9300
+[2023-05-31T15:23:03,677][TRACE][o.o.d.e.AwsEc2SeedHostsProvider] [ip-172-31-73-184] adding i-0c6ffdd10ebd3c2f1, address 172.31.74.156, transport_address 172.31.74.156:9300
+```
+
+## Troubleshooting
+
+### Trace Level Logs
+
+Enable `TRACE`-level logging in `opensearch.yml` to see more output.
+
+```yml
+logger.org.opensearch.discovery.ec2: trace
+```
+
+### Sample IMDS Query
+
+You may need to query IMDS without running OpenSearch. Use [this sample](https://github.com/dblock/aws-imds-sample) or copy the following code that makes a query to IMDS that looks for `running`, `pending` or `stopped` instances.
+
+```java
+DefaultCredentialsProvider credentialsProviderChain = DefaultCredentialsProvider.create();
+
+RetryPolicy retryPolicy = RetryPolicy.builder()
+  .numRetries(10)
+  .build();
+
+Ec2Client client = Ec2Client.builder()
+  .httpClientBuilder(ApacheHttpClient.builder())
+  .credentialsProvider(credentialsProviderChain)
+  .build();
+
+DescribeInstancesRequest describeInstancesRequest = DescribeInstancesRequest.builder()
+  .filters(
+    Filter.builder()
+      .name("instance-state-name")
+      .values("running", "pending", "stopped")
+      .build()
+  ).build();
+
+DescribeInstancesResponse describeInstancesResponse = client.describeInstances(describeInstancesRequest);
+for (final Reservation reservation : describeInstancesResponse.reservations()) {
+  System.out.println(reservation.reservationId());
+  for (final Instance instance : reservation.instances()) {
+    System.out.println("\t" + instance.publicDnsName());
+  }
+}
+```
diff --git a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java
index 4a78572e2e18f..3f7a8e1e03353 100644
--- a/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java
+++ b/plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/Ec2NameResolver.java
@@ -117,7 +117,7 @@ public InetAddress[] resolve(Ec2HostnameType type) throws IOException {
 
                 String metadataResult = urlReader.readLine();
                 if (metadataResult == null || metadataResult.length() == 0) {
-                    throw new IOException("no gce metadata returned from [" + url + "] for [" + type.configName + "]");
+                    throw new IOException("no ec2 metadata returned from [" + url + "] for [" + type.configName + "]");
                 }
                 logger.debug("obtained ec2 hostname from ec2 meta-data url {}: {}", url, metadataResult);
                 // only one address: because we explicitly ask for only one via the Ec2HostnameType
diff --git a/plugins/repository-s3/README.md b/plugins/repository-s3/README.md
new file mode 100644
index 0000000000000..03007e03b633e
--- /dev/null
+++ b/plugins/repository-s3/README.md
@@ -0,0 +1,25 @@
+# repository-s3
+
+The repository-s3 plugin enables the use of S3 as a place to store snapshots.
+
+## Testing
+
+### Unit Tests
+
+```
+./gradlew :plugins:repository-s3:test
+```
+
+### Integration Tests
+
+Integration tests require several environment variables.
+
+-  `amazon_s3_bucket`: Name of the S3 bucket to use.
+-  `amazon_s3_access_key`: The access key ID (`AWS_ACCESS_KEY_ID`) with r/w access to the S3 bucket.
+-  `amazon_s3_secret_key`: The secret access key (`AWS_SECRET_ACCESS_KEY`).
+-  `amazon_s3_base_path`: A relative path inside the S3 bucket, e.g. `opensearch`.
+-  `AWS_REGION`: The region in which the S3 bucket was created. While S3 buckets are global, credentials must scoped to a specific region and cross-region access is not allowed. (TODO: rename this to `amazon_s3_region` in https://github.com/opensearch-project/opensearch-build/issues/3615 and https://github.com/opensearch-project/OpenSearch/pull/7974.)
+
+```
+AWS_REGION=us-west-2 amazon_s3_access_key=$AWS_ACCESS_KEY_ID amazon_s3_secret_key=$AWS_SECRET_ACCESS_KEY amazon_s3_base_path=path amazon_s3_bucket=dblock-opensearch ./gradlew :plugins:repository-s3:s3ThirdPartyTest
+```