AWS (that is, Amazon Web Services) is a cloud service platform provided by Amazon; its free account provides one year of free service.
By default, the EC2 Linux server only opens port 22, the SSH service port (allowing inbound connections from all IPs). For any other managed services with a specific port, you need to manually open the corresponding port on the AWS firewall; for example, tomcat deployed on EC2 listens to port 8181, starts mysql, and listens to port 3306, you need to manually open the corresponding port as shown in the figure:
1. Click "Network and Security" - "Security Group" on the left menu
2. Then set the port in the pop-up port setting:
3. If a specific port is not set, such as 3306 of mysql, mysql startup will not report an error, but the local program cannot connect to port 3306.
Supplement: Port configuration, which can be configured when an instance is created.