Komodo Deployment Failures In VLANs: Git-Sourced Compose Files

Nov 26, 2025 by Alex Johnson 63 views

Troubleshooting Komodo Deployments on Separate VLANs with Git-Sourced Compose Files

Are you encountering deployment issues with Komodo when your periphery servers reside on a different VLAN, specifically when using Git-sourced Compose files? You're not alone. This article dives deep into the potential causes and solutions for this frustrating problem, offering insights and troubleshooting steps to get your deployments running smoothly. Let's explore why deployments might fail in this scenario and how to rectify it.

Understanding the Issue: VLANs, Git, and Komodo

At its core, this issue arises when deploying applications using Komodo, where the infrastructure spans multiple VLANs, and the deployment configurations are sourced from a Git repository. A VLAN (Virtual Local Area Network) logically separates network traffic, enhancing security and network management. In this context, the Komodo core server and Git server exist on one VLAN, while the periphery servers reside on another. The crucial detail is that while the core and Git servers can communicate with the periphery VLAN, the periphery VLAN is restricted from initiating connections back to the core and Git server VLAN.

The problem manifests specifically when the Compose files, which define the application deployment, are sourced from a Git repository. Deployments work perfectly fine when the Compose files are stored directly within the Komodo UI. This discrepancy hints at a communication pattern triggered by Git-sourced deployments that doesn't occur with UI-stored configurations. Understanding this difference is key to resolving the issue.

Potential Causes for Deployment Failure

Several factors could contribute to this deployment failure. Let's break down the most likely culprits:

1. Git Repository Access and Connectivity

The most obvious potential cause is a connectivity issue between the periphery server and the Git repository. When using Git-sourced Compose files, the periphery server needs to access the Git repository to fetch the necessary configuration files. If the periphery VLAN is restricted from initiating connections to the Git server's VLAN, this fetch operation will fail. This is especially true if the Git repository uses protocols like SSH or HTTPS, which require bidirectional communication for authentication and data transfer.

To verify this, you can try basic network connectivity tests from the periphery server, such as ping or telnet, to the Git server. If these tests fail, it confirms a network connectivity issue. Moreover, check the firewall rules and network policies to ensure that the periphery VLAN is explicitly allowed to access the Git server on the necessary ports (e.g., SSH port 22, HTTPS port 443).

2. Komodo Agent Communication

Komodo uses agents on the periphery servers to manage deployments. These agents typically communicate with the core server to receive instructions and report status. While the core server initiates most of this communication, there might be scenarios where the agent needs to send data back to the core server, especially during Git-related operations. For instance, after fetching the Compose file, the agent might need to notify the core server of the successful retrieval or report any errors.

If the periphery VLAN cannot initiate connections to the core server's VLAN, these communications might be blocked, leading to deployment failures. To troubleshoot this, examine the Komodo agent logs on the periphery server for any error messages related to connectivity or communication failures. Additionally, ensure that the firewall rules allow the Komodo agent to communicate with the core server on the designated ports.

3. DNS Resolution Issues

DNS resolution is another critical aspect to consider. The periphery server needs to resolve the hostname of the Git server and the Komodo core server to their respective IP addresses. If the DNS server configured on the periphery VLAN cannot resolve these hostnames, the deployment will fail. This issue is more likely to occur if you're using internal hostnames that are only resolvable within the core VLAN.

To diagnose DNS issues, use the nslookup or dig commands on the periphery server to query the hostnames of the Git server and the Komodo core server. If the resolution fails, verify the DNS settings on the periphery VLAN and ensure that the correct DNS servers are configured. You might need to add DNS entries to an internal DNS server or use a DNS forwarder to resolve external hostnames.

4. Git Submodules and Dependencies

If your Git repository includes submodules or relies on external dependencies fetched during the deployment process, these could introduce additional communication requirements. For example, if the Compose file references other Git repositories as submodules, the periphery server will need to access these submodules. Similarly, if the deployment process involves downloading artifacts from external sources, such as package repositories, the periphery server must be able to reach these sources.

To address this, ensure that the periphery VLAN has access to all necessary external resources. This might involve whitelisting specific IP addresses or domains in the firewall rules or configuring a proxy server for the periphery servers to use.

5. SSH Key Management and Authentication

When using SSH to access the Git repository, proper SSH key management is crucial. The periphery server needs to have the correct SSH keys configured to authenticate with the Git server. If the SSH keys are not correctly set up or if the Git server's SSH configuration restricts access from the periphery VLAN, deployments will fail.

Verify that the Komodo agent on the periphery server has the necessary SSH keys and that these keys are authorized on the Git server. Check the SSH logs on both the periphery server and the Git server for any authentication errors. Additionally, ensure that the Git server's known_hosts file contains the correct SSH host key for the Git server.

Troubleshooting Steps and Solutions

Now that we've explored the potential causes, let's outline a systematic approach to troubleshooting and resolving the issue:

Verify Network Connectivity: Start by confirming basic network connectivity between the periphery server and the Git server. Use ping and telnet to check if the periphery server can reach the Git server on the necessary ports (e.g., 22 for SSH, 443 for HTTPS). If connectivity is an issue, adjust firewall rules and network policies to allow traffic between the VLANs.
Check DNS Resolution: Use nslookup or dig on the periphery server to resolve the hostnames of the Git server and the Komodo core server. If DNS resolution fails, verify the DNS settings on the periphery VLAN and ensure that the correct DNS servers are configured.
Examine Komodo Agent Logs: Inspect the Komodo agent logs on the periphery server for any error messages related to connectivity, communication failures, or Git operations. These logs often provide valuable clues about the root cause of the problem.
Test Git Access: Try to clone the Git repository manually from the periphery server using the git clone command. This will help isolate any issues related to Git access and authentication. If the clone operation fails, verify SSH key configuration and Git server access permissions.
Review Firewall Rules: Carefully review the firewall rules and network policies between the periphery VLAN and the core/Git VLANs. Ensure that traffic is allowed in both directions on the necessary ports. Pay special attention to any rules that might be blocking communication initiated from the periphery VLAN.
Simplify the Deployment: As a troubleshooting step, try simplifying the deployment by removing any Git submodules or external dependencies. This can help determine if these factors are contributing to the issue.
Use Komodo UI Storage as a Control: Since deployments work correctly when Compose files are stored in the Komodo UI, use this as a control. Compare the deployment process when using UI-stored files versus Git-sourced files to identify any differences in communication patterns or resource access.

Solutions and Workarounds

Based on the troubleshooting steps, here are some potential solutions and workarounds:

Adjust Firewall Rules: The most common solution is to adjust firewall rules to allow the periphery VLAN to communicate with the core and Git VLANs on the necessary ports. This might involve creating specific rules to allow traffic from the periphery servers to the Git server (e.g., SSH port 22, HTTPS port 443) and the Komodo core server (on the agent communication port).
Configure a Proxy Server: If direct communication between the VLANs is not feasible, you can configure a proxy server in the core VLAN and configure the Komodo agents on the periphery servers to use this proxy for Git access and other external communication. This allows the periphery servers to access external resources without directly initiating connections to the core VLAN.
Use a Git Mirror: Another approach is to set up a Git mirror within the periphery VLAN. This mirror would periodically synchronize with the main Git repository and the periphery servers would then access the mirror instead of the main repository. This reduces the need for cross-VLAN communication.
Implement a Pull-Based Deployment: Instead of having the Komodo core server initiate deployments, you could implement a pull-based deployment strategy where the periphery servers periodically check for updates in the Git repository and initiate deployments themselves. This shifts the communication direction and reduces the need for the core server to initiate connections to the periphery VLAN.
Centralized Artifact Storage: If the deployment process involves downloading artifacts from external sources, consider setting up a centralized artifact storage within the core VLAN. The Komodo core server can then distribute these artifacts to the periphery servers, eliminating the need for them to access external sources directly.

Conclusion

Troubleshooting deployment failures in multi-VLAN environments requires a systematic approach. By understanding the communication pathways involved and the potential points of failure, you can effectively diagnose and resolve the issue. Remember to verify network connectivity, check DNS resolution, examine agent logs, and review firewall rules. By implementing the solutions and workarounds discussed in this article, you can ensure smooth and reliable Komodo deployments across your entire infrastructure.

For further reading on network troubleshooting and VLAN configurations, you might find valuable resources on trusted websites like Cisco's Networking Documentation.