NetBird Connectivity Issues: Troubleshooting Manual Restarts

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NetBird Intermittent Connectivity Loss: A Deep Dive into Manual Restarts

Experiencing intermittent connectivity issues with your NetBird routing peers? You're not alone! Many users have reported similar problems where connectivity to NetBird routing peers, especially VPC gateway instances, drops intermittently, making valuable infrastructure resources unreachable. The most frustrating part? The only reliable fix often involves manually restarting the NetBird service on the affected peer.

This article dives deep into this issue, exploring the symptoms, potential causes, and troubleshooting steps. We'll also look at user experiences and discuss potential solutions to help you achieve stable and reliable NetBird connectivity.

Understanding the Problem: Intermittent Connectivity Woes

So, what exactly does this intermittent connectivity loss look like? In many cases, users find that their client machines can no longer access resources behind the NetBird routing peers. This is particularly concerning when it affects redundant routing peers simultaneously, even when these peers are hosted on separate EC2 instances with independent network paths. It's like having a backup system that fails at the same time as the primary – definitely not ideal!

The common symptom is that the only consistent way to restore connectivity is by manually executing netbird down && netbird up on the problematic routing peer(s). This is a temporary fix, though. To mitigate the issue, some users have implemented automated daily restarts using cron jobs with retry logic and randomized delays. However, even with these measures, connectivity issues can still pop up randomly between scheduled restarts, often demanding manual intervention from the operations team. This obviously isn't a sustainable solution, especially when aiming for high availability and minimal downtime.

Replicating the Issue: A Step-by-Step Guide

Want to see if you can reproduce this behavior in your own environment? Here's a breakdown of the steps involved:

  1. Set up a self-hosted NetBird environment: This involves configuring routing peers to act as VPC gateways.
  2. Configure redundant routing peers: For high availability, it's common practice to set up two routing peers per VPC.
  3. Connect client machines: These clients will need to access resources through the routing peers.
  4. Initial operation: Everything should work smoothly initially, with clients able to access resources via the routing peers.
  5. The dreaded disconnect: After a random period (which can range from hours to days), clients start losing connectivity to resources behind the routing peers. This is where the frustration kicks in.
  6. Routing peer status: Checking the routing peer status often reveals that it's in an "Idle" or "Connecting" state for the affected client peers, with a tell-tale sign of "Last WireGuard handshake: -". This indicates a breakdown in the secure connection.
  7. Client-side status: On the client side, the NetBird status will show the routing peer in a perpetual "Connecting" state, further confirming the connectivity problem.
  8. The manual fix: The only reliable solution at this point is to SSH into the routing peer and run the netbird down && netbird up command. This effectively restarts the NetBird service and often restores connectivity, albeit temporarily.

Expected Behavior: Stable Connectivity is Key

Ideally, routing peers should maintain a stable and consistent connection with client peers. This is fundamental for reliable access to resources and a smooth user experience. The goal is to eliminate the need for manual intervention and ensure that the network operates without these disruptive connectivity drops.

Self-Hosted vs. Cloud: The Deployment Factor

It's important to note that this issue has been primarily reported in self-hosted NetBird deployments. This means the control plane is deployed on-premise, giving users more control but also increasing the complexity of managing the infrastructure. While NetBird Cloud offers a managed solution, self-hosting is often preferred for organizations with specific security or compliance requirements.

NetBird Versions and the Connectivity Problem

The intermittent connectivity issue seems to persist across different NetBird versions. Reports indicate that it affects a mix of client versions, including 0.59.10, 0.59.11, and 0.59.12. This suggests that the problem isn't tied to a specific version but rather points to a deeper underlying issue within the connection management or network stability.

On the routing peer side, version 0.59.12 on Amazon Linux 2023 seems to be commonly affected. However, the widespread nature across client versions suggests the problem isn't isolated to a particular operating system or NetBird version.

Ruling Out Other VPN Software: A Process of Elimination

One crucial step in troubleshooting is to rule out any conflicts with other VPN software. In most reported cases, users have confirmed that no other VPN software is installed on either the routing peers or the affected clients. This eliminates a potential source of interference and strengthens the focus on NetBird itself as the source of the issue.

Debugging the Issue: Analyzing the Status Output

To understand the problem better, examining the debug output from the routing peer is crucial. A typical scenario involves a peer connection getting stuck, as highlighted in the following anonymized status example:

mac.netbird.selfhosted:
NetBird IP: 100.87.11.0
Public key: hgw6obWwCwEMlURINDahgd+koxBc5gjYVajIINW0k0A=
Status: Connecting
-- detail --
Connection type: -
ICE candidate (Local/Remote): -/-
ICE candidate endpoints (Local/Remote): -/-
Relay server address:
Last connection update: 8 minutes, 21 seconds ago
Last WireGuard handshake: -
Transfer status (received/sent) 0 B/0 B

This output reveals several key details:

  • The peer's status is stuck in "Connecting".
  • There's no recent WireGuard handshake, indicated by "Last WireGuard handshake: -". This is a strong indicator of a broken connection.
  • Zero data transfer (0 B/0 B) further confirms that no communication is happening.

This pattern suggests that the connection establishment or maintenance process is failing, leading to the peer getting stuck in a connecting state without ever completing the handshake.

The Environment: AWS and VPC Gateways

Most users reporting this issue are deploying NetBird within an AWS environment, specifically using EC2 instances as routing peers. These peers often function as VPC gateways, providing access to resources like RDS databases and other EC2 instances within the VPC.

The architecture typically involves deploying two routing peers per VPC for redundancy, aiming for high availability. However, the simultaneous failure of both peers highlights a critical flaw in the failover mechanism, suggesting that the issue might be systemic rather than isolated to individual instances.

The network configuration often involves placing the routing peers behind an AWS Network Load Balancer (NLB) with an HTTP2Optional ALPN policy to support gRPC, which is used for communication within NetBird. While this setup is generally recommended for performance and scalability, it also introduces potential complexities that might contribute to the connectivity issues.

Mitigation Attempts: What Hasn't Worked?

Several mitigation attempts have been made to address this intermittent connectivity problem, but none have provided a complete solution:

  • Automated Daily Reconnections: Implementing cron jobs to periodically restart NetBird with retry attempts was an early attempt to mitigate the issue. While this helped reduce the frequency of manual interventions, it didn't eliminate the problem entirely.
  • Redundant Routing Peers: Deploying redundant routing peers was intended to provide failover capabilities. However, the fact that both peers can become unreachable simultaneously defeats this purpose, indicating a more fundamental problem.

These failed attempts underscore the complexity of the issue and highlight the need for a deeper understanding of the root cause.

Pattern Observations: Key Clues to the Root Cause

Analyzing the patterns of the intermittent connectivity issue reveals several crucial observations:

  • Random User Impact: The issue affects users randomly, regardless of the NetBird client version they're using. This suggests that the problem isn't tied to a specific client configuration or version.
  • Simultaneous Peer Failure: Both routing peers can fail simultaneously, even though they reside on separate instances. This points towards a systemic issue affecting the overall NetBird deployment rather than individual peer failures.
  • Manual Restart as a Temporary Fix: The fact that a manual netbird down && netbird up on the routing peer immediately resolves connectivity suggests a state management issue. The restart likely clears out stale connections or resets a faulty state, but the underlying cause remains unaddressed.

Potential Causes: A Hypothesis

Based on these observations, a leading hypothesis is that the issue stems from a connection state management problem within NetBird. It appears that NetBird may not be effectively detecting or recovering from stale peer connections automatically. This could be due to various factors, including:

  • Network Instability: Transient network issues or hiccups might disrupt the connection, leaving the peers in a confused state.
  • NAT Traversal Challenges: Network Address Translation (NAT) can sometimes interfere with peer-to-peer connections, especially if the NAT mappings expire prematurely.
  • Keepalive Mechanisms: The keepalive mechanisms within WireGuard or NetBird might not be aggressive enough to maintain the connection in the face of network fluctuations.
  • gRPC Issues: The use of gRPC over HTTP2Optional ALPN introduces complexities, and potential issues with the NLB configuration or gRPC implementation could contribute to the problem.

Troubleshooting Steps Taken: A Process of Elimination

Users experiencing this issue have already taken several troubleshooting steps, demonstrating a proactive approach to resolving the problem:

  • Reviewed NetBird Documentation: The official NetBird troubleshooting guide (https://docs.netbird.io/how-to/troubleshooting-client) has been consulted for common solutions.
  • Checked for Newer Versions: Users have confirmed they are running the latest 0.59.x version, ruling out version-specific bugs.
  • Searched for Similar Issues: Online forums and GitHub issues have been searched for similar reports, indicating a broader community awareness of the problem.
  • Restarted the NetBird Client: Restarting the client often provides a temporary fix, reinforcing the idea of a connection state issue.
  • Disabled Other VPN Software: The absence of other VPN software eliminates potential conflicts.
  • Checked Firewall Settings: Firewall settings, including the NLB ALPN policy, have been verified to ensure they are correctly configured.

Have You Seen This Before? Seeking Community Wisdom

One of the key questions raised by users is whether this pattern has been observed in other NetBird deployments. This highlights the importance of community knowledge and shared experiences in troubleshooting complex issues.

It seems like a connection state management issue where NetBird doesn't detect or recover from stale peer connections automatically. This is a critical point that warrants further investigation.

Moving Forward: Potential Solutions and Next Steps

Addressing this intermittent connectivity issue requires a multi-pronged approach:

  1. Deeper Dive into Logs: A thorough examination of NetBird logs on both the client and routing peer sides is crucial. Look for error messages, warnings, or any anomalies that might shed light on the connection failures.
  2. Network Analysis: Tools like tcpdump or Wireshark can help capture network traffic and analyze the communication between peers. This can reveal potential network-level issues or misconfigurations.
  3. Keepalive Tuning: Experimenting with different keepalive settings in WireGuard or NetBird might help maintain connections more effectively. This involves adjusting the frequency and timeout values for keepalive packets.
  4. gRPC Investigation: If gRPC is suspected, investigate the NLB configuration and gRPC implementation for potential issues. Ensure that the ALPN policy is correctly configured and that gRPC connections are being handled properly.
  5. NetBird Configuration Review: Double-check the NetBird configuration for any potential misconfigurations or suboptimal settings. Pay close attention to routing rules, DNS settings, and peer configurations.
  6. Community Engagement: Continue engaging with the NetBird community, sharing your experiences and seeking advice from other users and developers. Collaboration is key to finding solutions.

Conclusion: Towards Stable NetBird Connectivity

The intermittent connectivity issue with NetBird routing peers is a frustrating problem, but it's not insurmountable. By understanding the symptoms, exploring potential causes, and systematically troubleshooting the environment, you can work towards achieving stable and reliable NetBird connectivity.

Remember, this is a journey, and persistence is key. Share your findings, collaborate with the community, and don't hesitate to seek help when needed. Together, we can unlock the full potential of NetBird and build secure, reliable networks.