CentOS 7.x服务器重启后自动执行指定命令的实现方法咨询

Hey there! Let me walk you through a couple of reliable ways to get those commands running automatically right after your CentOS 7 server reboots. I’ll cover two methods—one quick and straightforward, another more robust for better control.

CentOS 7 still supports the classic rc.local approach for post-boot scripts, though you need to make sure it’s properly enabled first. Here’s how to set it up:

1. Open the rc.local file in your editor of choice:

   vi /etc/rc.d/rc.local
   

2. Scroll to the bottom and add your three commands in order:

   getenforce
   setenforce 0
   systemctl start httpd.service
   

   Note: getenforce will just output the current SELinux state, which will be logged in the rc-local service logs if you ever need to check it.
3. Give the file executable permissions—this is a crucial step since CentOS 7 disables this by default:

   chmod +x /etc/rc.d/rc.local
   

4. Enable and start the rc-local service to activate the setup:

   systemctl enable rc-local.service
   systemctl start rc-local.service
   

If you want better control over the task, proper logging, and standard service management, a custom systemd service is the way to go. This is the modern approach recommended for CentOS 7:

1. Create a new service file (we’ll name it post-boot-tasks.service):

   vi /etc/systemd/system/post-boot-tasks.service
   

2. Paste the following configuration into the file:

   [Unit]
   Description=Post-boot tasks: Check SELinux state, set to permissive, start httpd
   After=network.target
   
   [Service]
   Type=oneshot
   ExecStart=/usr/sbin/getenforce
   ExecStart=/usr/sbin/setenforce 0
   ExecStart=/usr/bin/systemctl start httpd.service
   RemainAfterExit=yes
   
   [Install]
   WantedBy=multi-user.target
   

   Let me break down a few key parts:
   • After=network.target: Ensures the tasks run after the network is up, which makes sense since httpd often relies on network connectivity.
   • Type=oneshot: Tells systemd this is a one-time task that finishes once all commands run.
   • RemainAfterExit=yes: Keeps the service marked as "active" even after the commands complete, which helps with status checks.
3. Reload systemd to recognize the new service:

   systemctl daemon-reload
   

4. Enable the service so it runs on every boot:

   systemctl enable post-boot-tasks.service
   

5. (Optional) Test it out manually to make sure everything works before rebooting:

   systemctl start post-boot-tasks.service
   

   You can check the logs anytime with:

   journalctl -u post-boot-tasks.service
   

If you want to permanently disable SELinux instead of just setting it to permissive on each boot, edit /etc/selinux/config and change SELINUX=enforcing to SELINUX=disabled. Then reboot—this way you won’t need the setenforce 0 command anymore. Also, if you’ve already run systemctl enable httpd.service, the systemctl start httpd command is redundant (but harmless to include anyway).

内容的提问来源于stack exchange，提问作者Zac Ram