[K8S series] Common problems and solutions for Weave Net troubleshooting

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When using Weave Net for container network configuration, there are some common failure scenarios you may encounter. Here are some common problems and their solutions:

List of Questions

1 Node cannot join the Weave Net network

solution

Check the network connectivity between nodes to make sure they can reach each other by IP address.

Check the node's firewall settings to make sure Weave Net traffic is allowed through.

Make sure Weave Net is properly installed on each node and use the correct command to join the node to the network.

Check the status of Weave Net to make sure all nodes are "ready".

Check Weave Net's logs for more detailed error messages.

2 Containers cannot communicate via Weave Net :

 solution

Check that the container is properly connected to the Weave Bridge device. The container's network interface can be checked with  ifconfig the or  ip a command.

Make sure the IP address of the container is valid and is 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 is properly configured with network routing rules.

3 Weave Net control node fails to start :

solution

Check if Docker is installed on the host and the Docker service is running.

Make sure you have administrator privileges when running the Weave Net commands.

Check the host's network settings to make sure there are no conflicting IP addresses or network configurations.

Check Weave Net's logs for more detailed error messages.

4 Network performance issues :

solution

Check the host's resource utilization, including CPU, memory, and network bandwidth. Make sure that the host resources are sufficient for the communication needs between the containers.

Consider using Weave Net's advanced configuration options, such as enabling encryption, adjusting IP address ranges, etc., to meet specific network needs.

If the network topology is large, 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 guidelines and solutions.

When using Weave Net for container network configuration, you may also encounter some of the following common failure scenarios and solutions:

5 Network connection failure :

solution

Check the network connectivity between the hosts to make sure they can reach each other by IP address.

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

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

6 Poor network performance :

solution

Check the host's resource utilization, including CPU, memory, and disk. Make sure the host has enough resources to handle Weave Net's network traffic.

Consider adjusting Weave Net's configuration parameters, such as MTU size, network timeout, etc., to improve network performance.

Check whether there is a performance bottleneck in the network device (network card, switch) of the host. It may be necessary to upgrade the hardware or optimize the configuration of the network device.

7 IP address conflict :

solution

Check the host and container IP addresses to make sure they are on the same network segment without conflicts.

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 that there are no manually configured conflicting IP addresses.

8 Weave Net Version Compatibility :

solution

Check that the version of Weave Net being used is compatible with the Kubernetes version. Make sure to use compatible version combinations.

If you encounter known issues with a specific version, try upgrading your Weave Net or Kubernetes version to get 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. Also, regularly update the version of Weave Net and related components for better stability and functionality.

Here are some other possible failure conditions and solutions:

9 DNS resolution problem :

solution

Check that the container is able to 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, pointing to the correct DNS server.

Check the host's DNS configuration to make sure the DNS server is reachable and working properly.

10 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.

11 Performance problems caused by insufficient resources :

solution

Check host and container resource utilization, including CPU, memory, and disk. Insufficient resources may result in degraded network performance.

Consider adjusting the container's resource limits to better meet network demands.

12 Conflicts between the container network plugin and other components :

solution

If you are using more than one container network plugin or if the network plugin conflicts with other components, it may cause network failures.

Make sure the container network plugin is compatible with other components (such as CNI plugins, Network Policy Controller, etc.) and that there are no conflicting configurations.

13 Logs and Monitoring :

solution

Check Weave Net's logs periodically 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 in a timely manner.

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 guidance and solutions.

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