fix(ec2): use regional private DNS names by aniketshukla1 · Pull Request #5033 · floci-io/floci

aniketshukla1 · 2026-10-03T21:40:25Z

Summary

Closes #4959.

Centralize the EC2 private DNS domain rule: us-east-1 uses ec2.internal and other regions use the regional compute.internal domain.
Apply it to instance, primary and secondary network-interface, container-backed instance, ECS metadata and EKS node names.
Resolve regional EC2 IP hostnames in the embedded DNS server while rejecting invalid region IDs.
Add EC2 Query protocol integration and focused unit coverage.

Type of change

Bug fix (fix:)
New feature (feat:)
Breaking change (feat!: or fix!:)
Docs / chore

AWS Compatibility

Previously RunInstances and CreateNetworkInterface returned the us-east-1 private DNS suffix in every region. The integration test validates both us-east-1 and us-west-2 through the existing EC2 Query protocol. No live AWS comparison was run.

Checklist

./mvnw test passes locally
New or updated integration test added
Commit messages follow Conventional Commits
I have no more than 2 open, non-draft pull requests in this repository (maintainers and dependency bots are exempt).

greptile-apps · 2026-10-05T14:56:17Z

Confidence Score: 4/5

[Medium risk] EC2 private DNS names now include the request region.

The PR’s DNS behavior appears sound, but the repository’s SDK-validation requirement should be satisfied before merging.

Findings

SDK validation is missing ▶

Summary

The PR centralizes regional EC2 private DNS naming across instances, network interfaces, ECS, and EKS, and extends embedded DNS resolution to regional names.

The previous region-catalog restriction and inline class qualification have been addressed.
The new management-API integration coverage uses handcrafted requests rather than SDK validation.

_{Reviews (2) · Last reviewed commit: "fix(ec2): resolve private DNS for patter..."}

pgermosen

@aniketshukla1 Thanks, pulling the domain rule into one helper is a nice cleanup.

Greptile's DNS point holds up, though. Floci accepts requests for any region that fits a partition's naming pattern, not just the published ones, so EC2 can hand out a name like ip-10-0-0-5.us-new-1.compute.internal that the new isRegionId check then refuses to resolve. Using the same check the request gate uses, RegionResolver.isKnownRegion, would keep the two in step.

Two small things while you're in there: the inline org.hamcrest.Matchers.equalTo in the integration test wants an import, and removing the search-domain constant in EcsTaskMetadataController left its doc comment behind on its own.

greptile-apps · 2026-10-05T17:43:07Z

+            ExtractableResponse<Response> instanceResponse = given().formParam("Action", "RunInstances")
+                    .formParam("ImageId", "ami-0abcdef1234567890")
+                    .formParam("InstanceType", "t3.micro")
+                    .formParam("MinCount", "1")
+                    .formParam("MaxCount", "1")
+                    .formParam("SubnetId", subnetId)
+                    .header("Authorization", auth)
+                    .when().post("/").then().statusCode(200).extract();


SDK validation is missing

This new test checks DescribeSubnets, RunInstances, DescribeInstances, and CreateNetworkInterface only with handcrafted Query requests. The repository guide calls for SDK-based validation where possible, particularly for management APIs. Please satisfy that requirement before merging so the test also checks that an EC2 SDK client can consume the regional private DNS names.

Context Used: AGENTS.md (source)

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

pgermosen

@aniketshukla1 Thanks, all three look right, and the us-new-1 test pins the DNS part. No need for the SDK test Greptile asked for: this changes a value, not the wire shape. I dropped the draft note and put the checklist back to the template in the description, since it becomes the squash commit.

… and the master (#5169) * fix(emr): use the cluster's regional private DNS domain for instances and the master ListInstances built every synthetic instance's PrivateDnsName as ip-10-0-0-N.ec2.internal, the us-east-1 domain, in every region, while RunJobFlow set MasterPublicDnsName to <region>.compute.internal, which is wrong in us-east-1. Both now use the shared EC2 helper, so names end in ec2.internal in us-east-1 and <region>.compute.internal elsewhere, as EC2 itself does since #5033. * fix(emr): report the regional master DNS name for a cluster stored before the fix DescribeCluster returned the stored MasterPublicDnsName, so a us-east-1 cluster persisted before the previous commit kept reporting <region>.compute.internal after an upgrade. The name is now derived from the cluster's region when the response is built.

* fix(ec2): use regional private DNS names * fix(ec2): resolve private DNS for pattern regions Signed-off-by: Matheus Oliveira <matheus.6148@gmail.com>

… and the master (floci-io#5169) * fix(emr): use the cluster's regional private DNS domain for instances and the master ListInstances built every synthetic instance's PrivateDnsName as ip-10-0-0-N.ec2.internal, the us-east-1 domain, in every region, while RunJobFlow set MasterPublicDnsName to <region>.compute.internal, which is wrong in us-east-1. Both now use the shared EC2 helper, so names end in ec2.internal in us-east-1 and <region>.compute.internal elsewhere, as EC2 itself does since floci-io#5033. * fix(emr): report the regional master DNS name for a cluster stored before the fix DescribeCluster returned the stored MasterPublicDnsName, so a us-east-1 cluster persisted before the previous commit kept reporting <region>.compute.internal after an upgrade. The name is now derived from the cluster's region when the response is built. Signed-off-by: Matheus Oliveira <matheus.6148@gmail.com>

fix(ec2): use regional private DNS names

83c316a

hectorvent added bug Something isn't working ec2 Amazon Elastic Compute Cloud (EC2) ecs Amazon Elastic Container Service (ECS) eks Amazon Elastic Kubernetes Service (EKS) labels Oct 4, 2026

aniketshukla1 marked this pull request as ready for review October 5, 2026 14:52

aniketshukla1 requested review from hectorvent and pgermosen as code owners October 5, 2026 14:52

greptile-apps Bot reviewed Oct 5, 2026

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Comment thread src/main/java/io/github/hectorvent/floci/core/common/dns/EmbeddedDnsServer.java Resolved

Comment thread src/test/java/io/github/hectorvent/floci/services/ec2/Ec2PrivateDnsRegionIntegrationTest.java Resolved

pgermosen reviewed Oct 5, 2026

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pgermosen added the waiting-author Review posted; waiting on the PR author to respond label Oct 5, 2026

fix(ec2): resolve private DNS for pattern regions

f48e798

greptile-apps Bot reviewed Oct 5, 2026

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pgermosen approved these changes Oct 5, 2026

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pgermosen removed the waiting-author Review posted; waiting on the PR author to respond label Oct 5, 2026

pgermosen merged commit 4fb52e0 into floci-io:main Oct 5, 2026
27 checks passed

hectorvent mentioned this pull request Oct 6, 2026

fix(emr): use the cluster's regional private DNS domain for instances and the master #5169

Merged

5 of 8 tasks

qodo-code-review Bot mentioned this pull request Oct 14, 2026

fix(partitions): source the China CloudFront suffix and GovCloud API Gateway zones #5618

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fix(ec2): use regional private DNS names - #5033

fix(ec2): use regional private DNS names#5033
pgermosen merged 2 commits into
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aniketshukla1:fix/ec2-private-dns-4959

aniketshukla1 commented Oct 3, 2026 •

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Summary

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AWS Compatibility

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Confidence Score: 4/5

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aniketshukla1 commented Oct 3, 2026 •

edited by pgermosen

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greptile-apps Bot commented Oct 5, 2026 •

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