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Oct 13, 2025 by wbrum.org 129 views

DNS Resolution Spam for Registry.npmjs.org: A Critical Issue in Hoarder Container

In the world of software development, containerization has become a crucial aspect of deploying and managing applications. Docker containers, in particular, have gained immense popularity due to their lightweight and portable nature. However, with the increasing use of containers, issues like DNS resolution spam have started to surface. In this article, we will delve into the problem of DNS resolution spam for registry.npmjs.org in the Hoarder container and explore possible solutions to mitigate this issue.

Thanks to my Pi-hole setup, I was able to identify a significant issue with the Hoarder container. It was sending around 3-4 DNS resolution queries for registry.npmjs.org per second. This excessive DNS traffic is undesirable, as it can cause CPU usage issues on the DNS resolver (Pi-hole) and may also overwhelm DNS request limits for other providers. The root cause of this issue is still unclear, but I suspect it is related to the Hoarder container rather than the Meilisearch or Chrome containers.

To reproduce this issue, follow these steps:

Spin up a Hoarder Docker Container: Start a new instance of the Hoarder container using the following command:

docker run -d --name hoarder hoarder:0.22.0

2. **Use `tcpdump` to Monitor DNS Request Traffic**: Run the following command to capture DNS request traffic:
   ```bash
tcpdump -i any -n -s 0 -c 100 -w dns_traffic.pcap port 53

This will capture 100 DNS packets and save them to a file named dns_traffic.pcap. 3. Observe DNS Resolution Requests: Analyze the captured DNS traffic using a tool like Wireshark or tcpdump. You should see the DNS resolution requests being spammed for registry.npmjs.org.

The expected behavior is that the Hoarder container should not send excessive DNS resolution requests for registry.npmjs.org. The container should only send necessary DNS requests to resolve package dependencies.

Unfortunately, I do not have any screenshots or additional context to provide, as this issue is related to DNS traffic and cannot be visually represented.

The issue was observed on a Debian 12 VM running the Hoarder Docker container.

The Hoarder version used to reproduce this issue is 0.22.0.

Yes, I have checked the troubleshooting guide and have not found a solution to this problem.

To mitigate this issue, consider the following possible solutions:

Configure DNS caching: Configure the DNS resolver to cache DNS responses for a longer period. This can help reduce the number of DNS requests sent to the DNS server.
Use a DNS proxy: Use a DNS proxy like Pi-hole to cache and filter DNS requests. This can help reduce the load on the DNS server and prevent excessive DNS traffic.
Optimize DNS settings: Optimize DNS settings on the Hoarder container to reduce the number of DNS requests sent. This can include configuring the DNS timeout, DNS retry count, and DNS cache size.
Upgrade Hoarder version: Upgrade the Hoarder version to the latest available version, which may include bug fixes and performance improvements.

In conclusion, the issue of DNS resolution spam for registry.npmjs.org in the Hoarder container is a critical problem that can cause CPU usage issues and overwhelm DNS request limits. By following the steps to reproduce this issue and exploring possible solutions, developers can mitigate this problem and ensure smooth operation of their applications.
DNS Resolution Spam for Registry.npmjs.org: A Critical Issue in Hoarder Container - Q&A

In our previous article, we discussed the issue of DNS resolution spam for registry.npmjs.org in the Hoarder container. This problem can cause CPU usage issues and overwhelm DNS request limits, leading to performance degradation and potential downtime. In this article, we will address some frequently asked questions (FAQs) related to this issue and provide additional insights to help developers mitigate this problem.

A: DNS resolution spam refers to the excessive and unnecessary DNS requests sent to a DNS server. In the case of the Hoarder container, it is sending around 3-4 DNS resolution queries for registry.npmjs.org per second, which is undesirable and can cause performance issues.

A: DNS resolution spam can cause CPU usage issues on the DNS resolver and may also overwhelm DNS request limits for other providers. This can lead to performance degradation, potential downtime, and increased costs.

A: The possible causes of DNS resolution spam in the Hoarder container are still unclear, but it is suspected to be related to the Hoarder container rather than the Meilisearch or Chrome containers. Further investigation is required to determine the root cause of this issue.

A: To reproduce this issue, follow these steps:

Spin up a Hoarder Docker container.
Use tcpdump to monitor DNS request traffic.
You'll see the DNS resolution requests being spammed for registry.npmjs.org.

A: The expected behavior is that the Hoarder container should not send excessive DNS resolution requests for registry.npmjs.org. The actual behavior is that the Hoarder container sends around 3-4 DNS resolution queries for registry.npmjs.org per second.

A: Consider the following possible solutions:

Configure DNS caching.
Use a DNS proxy like Pi-hole.
Optimize DNS settings on the Hoarder container.
Upgrade Hoarder version.

A: To configure DNS caching, you can use a DNS caching library like dnscache or unbound. You can also configure the DNS resolver to cache DNS responses for a longer period.

A: To use a DNS proxy like Pi-hole, you can install Pi-hole on your system and configure it to cache and filter DNS requests. This can help reduce the load on the DNS server and prevent excessive DNS traffic.

A: To optimize DNS settings on the Hoarder container, you can configure the DNS timeout, DNS retry count, and DNS cache size. You can also use a DNS settings library like dnssettings to simplify the process.

A: To upgrade Hoarder version, you can check the official Hoarder documentation for the latest version and follow the upgrade instructions. This may involve updating the Docker image or reinstalling the Hoarder container.

In conclusion, the issue of DNS resolution spam for registry.npmjs.org in the Hoarder container is a critical problem that can cause CPU usage issues and overwhelm DNS request limits. By understanding the possible causes and solutions to this issue, developers can mitigate this problem and ensure smooth operation of their applications.