Weave Net Troubleshooting FAQ

Weave Net container network configuration can fail for a number of common reasons. Let’s look at some of the common problems and their solutions.

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Here are some common problems and their solutions:

List of Questions

A node cannot join the Weave Net network:
Solution

• Check network connectivity between nodes to ensure they can reach each other via IP addresses.
• Check the node’s firewall settings to ensure that Weave Net traffic is allowed.
• Make sure Weave Net is installed correctly on each node and use the correct commands to join the node to the network.
• Check the status of the Weave Net to ensure that the status of all nodes is “ready”.
• Check the Weave Net logs for more detailed error information.

Containers cannot communicate via Weave Net:
Solution

• Check that the container is properly connected to the Weave Bridge device. The network interface of the container can be checked with the ifconfigor ip a command.
• Make sure the container’s IP address is valid and falls within the Weave Net IP address range.
• Check the container’s firewall settings to make sure Weave Net traffic is allowed.
• Make sure that the host where the container is located has successfully joined the Weave Net network and that the network topology is correct.
• Check that the container has correctly configured network routing rules.

Weave Net control node fails to start:
Solution

• Check whether Docker is installed on the host and the Docker service is running.
• Make sure you have administrator rights when running Weave Net commands.
• Check the host’s network settings to make sure there are no conflicting IP addresses or network configurations.
• Check the Weave Net logs for more detailed error information.

Network performance issues:
Solution

• Check the host’s resource utilization, including CPU, memory, and network bandwidth. Ensure that host resources are sufficient to meet the communication needs between containers.
• Consider using Weave Net’s advanced configuration options, such as enabling encryption, adjusting IP address ranges, and more, to meet your specific network needs.
• If the network topology is large, you can consider increasing the number of Weave Net control nodes to improve performance and stability.
• When encountering a failure situation, it is recommended to refer to Weave Net’s official documentation and community support resources for more detailed troubleshooting guides and solutions.
• When using Weave Net for container network configuration, you may also encounter the following common failure conditions and solutions:

Network connection failure:
Solution

Check network connectivity between hosts to ensure they can reach each other via IP addresses.

Check the configuration of your network devices (switches, routers) to ensure there are no restrictions blocking Weave Net traffic.

Use network diagnostic tools (such as ping, and traceroute) to check the network connection and determine the point of failure.

Low network performance:
Solution

• Check the host’s resource utilization, including CPU, memory, and disk. Ensure that the host has sufficient resources to handle Weave Net’s network traffic.
• Consider adjusting Weave Net configuration parameters, such as MTU size, network timeout, etc., to improve network performance.
• Check whether there are performance bottlenecks in the host’s network devices (network cards, switches). It may be necessary to upgrade the hardware or optimize the network device configuration.

IP address conflict:
Solution

• Check the host and container IP addresses to make sure they do not conflict within the same network segment.
• Make sure that the Weave Net’s IP address range does not overlap with other networks to avoid conflicts.
• Check the network configuration of the host and container to ensure there are no manually configured conflicting IP addresses.

Weave Net version compatibility:
Solution

• Check whether the Weave Net version you are using is compatible with the Kubernetes version. Make sure to use a compatible version combination.
• If you encounter known issues with a specific version, try upgrading the Weave Net or Kubernetes version to get the fixed issues.
• If you encounter a failure situation, it is recommended to refer to Weave Net’s official documentation, community discussions, and support channels for more detailed troubleshooting guides and solutions. In addition, regularly updating the versions of Weave Net and related components can achieve better stability and functionality.

Here are some other possible failure conditions and solutions:

DNS resolution issues:
Solution

• Check whether the container can resolve DNS correctly. Run nslookup the command to test whether the container can resolve the hostname and domain name.
• Make sure the container’s DNS is configured correctly and points to the correct DNS server.
• Check the host’s DNS configuration to ensure that the DNS server is accessible and functioning properly.

Network security policy restrictions :
Solution

• Check the network security policies of the host where the container is located and the Kubernetes cluster, such as Network Policies or firewall rules, to ensure that communication between containers is not restricted.
• Make sure the required ports are open between the container and the host and that network traffic can pass through normally.

Performance issues caused by insufficient resources :
Solution

• Check host and container resource utilization, including CPU, memory, and disk. Insufficient resources may cause network performance to degrade.
• Consider adjusting the container’s resource limits to better meet network demands.

Conflict between container network plug-ins and other components:
Solution

• Network failures may occur if multiple container network plug-ins are used or if the network plug-ins conflict with other components.
• Ensure that the container network plug-in is compatible with other components (such as CNI plug-ins, network policy controllers, etc.) and that there are no conflicting configurations.

Logging and monitoring:
Solution

• Check Weave Net’s logs regularly to catch any errors or anomalies.
• Use appropriate monitoring tools to track network performance and failure conditions so that problems can be identified and resolved promptly.
• If you encounter other failure conditions, it is recommended to refer to Weave Net’s official documentation, community support, and related troubleshooting resources for more detailed guides and solutions.