To troubleshoot the issue of services failing to start after a reboot of your CN2 VPS in Japan, you first need to identify several common causes of service startup failures. The most common cause is that the service isn't configured to start automatically at boot. Many software programs don't automatically load into the system's startup list after installation and only run after manually executing the startup command. If the service doesn't have the startup configuration configured, it won't load with the system. This problem often manifests as running normally before the reboot but completely stopping afterward.
Another possible cause is improperly loaded dependencies. Most services don't run in isolation; they rely on system components, drivers, or other services. For example, database services rely on mounted storage volumes, and web services rely on properly configured network and firewall rules. If certain dependencies aren't loaded promptly during system startup, the target service may fail to start. This is particularly common in VPS environments with additional mounted disks or complex network configurations.
Configuration file errors are also a common culprit. Some service configuration files may not be detected during runtime, but when the system reboots and reloads, syntax errors, path errors, or parameter conflicts can cause the service to fail to start. These issues are typically recorded in system logs or the service's own error logs.
Intervention by security mechanisms is also crucial. In distributions like CentOS and Rocky Linux, SELinux and firewalls (firewalld, iptables) may prevent services from running properly. If the administrator has manually adjusted service rules before a reboot, but these adjustments are not persistent, then when the system restores the default security policy after a reboot, the service may fail to start due to blocked ports or restricted permissions.
For Japan CN2 VPSs, the specificities of virtualization environments must also be considered. The virtualization technology used by some service providers may reassign network cards, disk mount points, or kernel modules upon reboot. If applications that rely on these resources don't dynamically adapt, startup failures can occur. For example, some older applications hard-code network card names. If the network card naming convention changes after a VPS reboot, this can cause configuration discrepancies.
Administrators should adopt a systematic approach to troubleshooting these issues. The first step is to check the service status. You can use systemctl status service_name or service service_name status to get the current running status of the service. If it displays "failed" or "inactive," you should further review the log information. Detailed error messages for most services can be found in journalctl -xe , which often directly point to the root cause of the problem.
The second step is to check the automatic startup configuration. For systemd-based systems, use systemctl enable service_name to add the service to the startup list and then verify the successful setup with systemctl is-enabled service_name . If the service still fails to start, use systemctl list-dependencies multi-user.target to check the dependencies and confirm that other dependent services are running properly.
The third step is to verify the configuration file. For Nginx, for example, you can use nginx -t to check the configuration file syntax. For MySQL, you can check /var/log/mysqld.log or /var/log/mysql/error.log for specific error messages. Often, incorrect configuration file paths or permissions are the direct cause of service startup failure.
The fourth step is to check the firewall and SELinux. Use firewall-cmd --list-all to view open ports and confirm whether the service port is included. Use getenforce to check the SELinux status. If it is in Enforcing mode, use the audit2allow tool to generate policy rules to allow the relevant service to access resources. If the service starts normally with SELinux disabled but fails after enabling it, the problem lies with policy restrictions.
The fifth step is to monitor system resources and dependencies. In some cases, insufficient memory or disk space on the VPS can cause service startup failures. Use free -m to check memory usage and df -h to check free disk space. If insufficient resources are the problem, consider expanding capacity or optimizing the application. Additionally, if the database or storage volume a service depends on is not mounted, manually mount the disk using mount -a or check whether /etc/fstab is configured correctly.
Some applications fail to start after a reboot because the log directory or PID file was not properly cleaned up. Many services check for the presence of PID files during startup. If a residual file doesn't correspond to a running process, the service will mistakenly believe it's already running, ultimately causing startup failure. The solution is to manually delete the residual PID file, for example, by running rm -f /var/run/service-name/*.pid, and then restart.
After resolving the specific issue, administrators should also implement long-term prevention and optimization measures. First, ensure that all critical services are configured to automatically start at boot and verify them regularly. Second, standardize the configuration file modification process, for example, by using Git to track configuration changes to prevent startup failures caused by errors. Third, strengthen the monitoring system by using tools like Zabbix and Prometheus to monitor service status in real time. This will provide immediate alerts if a service fails to start after a restart.
In addition, it's recommended to implement multi-node redundancy on the Japan CN2 VPS to prevent a single server failure from causing overall service unavailability. For example, a load balancer can be set up across multiple VPSs to ensure that even if a node fails to recover after a reboot, other nodes can still take over traffic. For database services, deploying master-slave replication or a high-availability architecture can improve overall reliability.
It's worth emphasizing that while service failure after a reboot is common, it often reflects deficiencies in system configuration and operational standards. In production environments, server reboots should be avoided during peak hours, and thorough verification and pre-emptive planning should be conducted beforehand. For example, you can use systemctl daemon-reexec to simulate a partial service reload rather than directly rebooting the entire server. If a reboot is necessary, carefully check dependencies and configurations beforehand to ensure they are fully functional.
