Exit Code
退出状态码（Exit Code） 是 Linux 中进程退出的原因指引。状态码在 0～255 之间，0 表示正常退出；状态码在 1～128 之间表示程序因为自身原因退出；状态码区间为 129 - 255 表示因外界中断导致程序退出。
常见的 退出状态码 如下所示 [1]：
| Code | Name | What it means |
|---|---|---|
| Exit Code 0 | Purposely stopped | Used by developers to indicate that the container was automatically stopped |
| Exit Code 1 | Application error | Container was stopped due to application error or incorrect reference in the image specification |
| Exit Code 125 | Container failed to run error | The docker run command did not execute successfully |
| Exit Code 126 | Command invoke error | A command specified in the image specification could not be invoked |
| Exit Code 127 | File or directory not found | File or directory specified in the image specification was not found |
| Exit Code 128 | Invalid argument used on exit | Exit was triggered with an invalid exit code (valid codes are integers between 0-255) |
| Exit Code 134 | Abnormal termination (SIGABRT) | The container aborted itself using the abort() function. |
| Exit Code 137 | Immediate termination (SIGKILL) | Container was immediately terminated by the operating system via SIGKILL signal |
| Exit Code 139 | Segmentation fault (SIGSEGV) | Container attempted to access memory that was not assigned to it and was terminated |
| Exit Code 143 | Graceful termination (SIGTERM) | Container received warning that it was about to be terminated, then terminated |
| Exit Code 255 | Exit Status Out Of Range | Container exited, returning an exit code outside the acceptable range, meaning the cause of the error is not known |
如果 退出状态码 大于等于 128，表示进程被接收到的信号杀死，退出状态码 减去 128 就是信号值。比如 退出状态码 为 137 表示收到 SIGKILL（信号值为 9）。
可以通过 Linux Man Page 查看所有的信号值。
What are Container Exit Codes
Exit codes are used by container engines, when a container terminates, to report why it was terminated.[1:1]