"Server Connection Error" Is Displayed After the Kernelgateway Process Is Stopped

Symptom

After the kernelgateway process is stopped, the following error message is displayed and a kernel cannot be selected.

Figure 1 Server Connection Error

Figure 2 Failed to select a kernel

Possible Causes

The fault is caused by misoperations.

Solution

1. Open the terminal window and run the following commands to start the kernelgateway service:

   API_TYPE=kernel_gateway.jupyter_websocket
   LOG_DIR="/home/ma-user/log"
   mkdir -p ${LOG_DIR}
   KERNEL_GATEWAY_LOG_FILE="${LOG_DIR}/kernelgateway-`date +"%Y-%m-%d-%Z-%H-%M-%S"`.log"
   
   jupyter kernelgateway --KernelGatewayApp.ip=${HOST_IP} --KernelGatewayApp.port=8889 --KernelGatewayApp.api=${API_TYPE} --KernelGatewayApp.auth_token=${JPY_AUTH_TOKEN} --JupyterWebsocketPersonality.list_kernels=True --debug >> "${KERNEL_GATEWAY_LOG_FILE}" 2>&1 &
   chmod 640 ${KERNEL_GATEWAY_LOG_FILE}

2. Run the ps -ef command to check whether the process is started.
   Figure 3 Check whether the process is started