Problem description
An overflow in the UDP cache of a Linux instance may affect the network performance of the Linux instance and thus the instance cannot connect remotely.
Cause
The value of the /etc/sysctl.conf
in the net.ipv4.udp_mem
file is set too low. The /etc/sysctl.conf
file stores system configuration information. If parameters are incorrectly configured, the network performance of Linux instances may be affected.
Solution
Alibaba Cloud reminds you that:
- Before you perform operations that may cause risks, such as modifying instance configurations or data, we recommend that you check the disaster recovery and fault tolerance capabilities of the instances to ensure data security.
- You can modify the configurations and data of instances including but not limited to Elastic Compute Service (ECS) and Relational Database Service (RDS) instances. Before the modification, we recommend that you create snapshots or enable RDS log backup.
- If you have authorized or submitted sensitive information such as the logon account and password in the Alibaba Cloud Management Console, we recommend that you modify such information in a timely manner.
- Remotely log on to the Linux instance through VNC. For more information about how to log on remotely, see ECS connection methods overview.
- Run the following command to edit the
/etc/sysctl.conf
file:Note: back up the data before modifying the configuration file.
vim /etc/sysctl.conf
- Press A to adjust the value of the
net.ipv4.udp_mem
parameter as needed. Then, press Esc to exit the edit mode. Enter: WQ
and pressEnter
. Save and exit.Description
A similar output is displayed.: WQ
in colon:
Need to pressShift
+:
Key output.- In this topic, the value of the
net.ipv4.udp_mem
parameter is819213107267108864
. Adjust the value as needed.
- Run the following command to make the configuration take effect.
sysctl -p
Application scope
- Elastic Compute Service