Error handling - Function Compute - Alibaba Cloud Documentation Center

This topic describes common errors in custom runtimes and how to troubleshoot the errors.

Failed to start a function instance

Example

The function cannot be started. Failed to start function instance. Error: the file /code/bootstrap is not exist

Troubleshooting

A function instance may fail to be started due to an exception that occurred in the startup command or the absence of the startup command.

By default, Function Compute uses /code/bootstrap as the startup command if the Startup Command parameter is not configured. If the file is not contained in the code package, you can add the /code/bootstrap script or modify the Startup Command parameter.
If the Startup Command parameter is configured, check whether the specified file exists by referring to the error message, which may indicate that the file does not exist (example: "Error: the file xxx is not exist").

For more information about how to configure Startup Command, see Principles.

Function instance health check failed

Example

Function instance health check failed on port 9001 in 120 seconds.\nLogs:

Troubleshooting

If a function instance fails to pass the health check, a possible cause is that the listening IP address or port that is specified in the code is incorrect. After a function instance is started, Function Compute performs a Layer-4 connectivity check based on the port configured for the function. If the check fails within the timeout period, a "Function instance health check failed" error is reported.

To avoid this issue, ensure that the listening IP address and port meet the following requirements:

Listening IP address
The listening IP address that is configured in the code must be 0.0.0.0 or *, and cannot be set to 127.0.0.0 or localhost.
Listening port
The listening port must be the same as the listening port that is configured for the function. The default listening port for a custom runtime is 9000.
- If you use the default port, make sure that the port on which the HTTP server listens in the code is also 9000.
- If you have configured the Listening Port parameter for your function, make sure that the port on which the HTTP server listens in the code is consistent with the value of Listening Port.

For more information about how to configure Listening Port, see Requirements for HTTP server configurations.

Function instance exited unexpectedly

Example

Function instance exited unexpectedly(code 2, message:no such file or directory) with start command '/code/bootstrap '.
Logs:

Function instance exited unexpectedly: A function instance unexpectedly exited.
code 2, message:no such file or directory: The Linux exit code of the instance startup process and description of the code.
with start command '/code/bootstrap ': The startup command of the instance.

Note

The exit code and the description of the exit code are provided only for reference. In some cases, the code does not carry the conventional meaning in any way.

Troubleshooting

No executable permissions for the startup command
```
The function cannot be started. Function instance exited unexpectedly(code 13, message:permission denied) with start command '/code/bootstrap '.
```
In most cases, code 13, message:permission denied is reported if no executable permissions are configured for the instance startup command. You can run the chmod 755 bootstrap, chmod 777 bootstrap, or chmod +x bootstrap command to grant the executable permissions to the file before you package the code.
File does not exist
```
Function instance exited unexpectedly(code 2, message:no such file or directory) with start command 'python3 not_exist_file.py '.
Logs:xxx
```
In most cases, code 2, message:no such file or directory is reported if the file in the startup parameters does not exist. In some cases, code 2, message:no such file or directory may not be reported. In these cases, you must troubleshoot the error based on error logs.
The following section describes the error messages that are returned for different programming languages when the file specified in the startup command does not exist.
- Python
  If the instance startup command is python3 not_exist_file.py, code 2, message:no such file or directory is reported.
  If you add the startup command to a shell script and change the startup command to /code/bootstrap, an error message that indicates the /code/not_exist_file.py file does not exist is reported.
  Example shell script
  #!/bin/bash python3 not_exist_file.py
  Error message
  Function instance exited unexpectedly(code 2, message:no such file or directory) with start command '/code/bootstrap '. Logs:python3: can't open file '/code/not_exist_file.py': [Errno 2] No such file or directory
- Node.js
  The following error message is reported if you set the instance startup command to npm run start and the script startup command in package.json to node ./not_exist_file.js:
```
Function instance exited unexpectedly(code 1, message:operation not permitted) with start command 'npm run start '.
Logs:> nodejs-express@0.0.0 start /code
> node ./not_exist_file.js

internal/modules/cjs/loader.js:905
  throw err;
  ^

Error: Cannot find module '/code/not_exist_file.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:902:15)
    at Function.Module._load (internal/modules/cjs/loader.js:746:27)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:75:12)
    at internal/main/run_main_module.js:17:47 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}
npm ERR!  code ELIFECYCLE
npm ERR!  errno 1
 ERR!  nodejs-express@0.0.0 start: `node ./not_exist_file.js`
 npm ERR!
 ERR!  Failed at the nodejs-express@0.0.0 start script.
npm ERR!  This is probably not a problem with npm. There is likely additional logging output above.

npm ERR!  A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2022-10-31T08_02_29_434Z-debug.log
```
  The error log message "Error: Cannot find module '/code/not_exist_file.js'" indicates that the error is caused by the absence of the /code/not_exist_file.js file. The exit code is code 1, message:operation not permitted.
  A similar error is reported if the instance startup command is set to node ./not_exist_file.js.
- Java
  The following error message is reported if you set the instance startup command to java -Dserver.port=9000 -jar target/not_exist_file.jar:
```
Function instance exited unexpectedly(code 1, message:operation not permitted) with start command 'java -Dserver.port=9000 -jar target/not_exist_file.jar '.
Logs:Error: Unable to access jarfile target/not_exist_file.jar
```
  The error log message "Unable to access jarfile target/not_exist_file.jar" indicates that the error is caused by the absence of the target/not_exist_file.jar file. The exit code is code 1, message:operation not permitted.
- PHP
  The following error message is reported if you set the instance startup command to php not_exist_file.php:
```
Function instance exited unexpectedly(code 1, message:operation not permitted) with start command 'php not_exist_file.php '.
Logs:Could not open input file: not_exist_file.php
```
  The error log message "Could not open input file: not_exist_file.php" indicates that the error is caused by the absence of the not_exist_file.php file. The exit code is code 1, message:operation not permitted.
- .NET Core
  The following error message is reported if you set the instance startup command to dotnet ./target/NotExistFile.dll:
```
Function instance exited unexpectedly(code 145) with start command 'dotnet ./target/NotExistFile.dll '.
Logs:Could not execute because the application was not found or a compatible .NET SDK is not installed.
Possible reasons for this include:
  * You intended to execute a .NET program:
      The application './target/NotExistFile.dll' does not exist.
  * You intended to execute a .NET SDK command:
      It was not possible to find any installed .NET SDKs.
      Install a .NET SDK from:
        https://aka.ms/dotnet-download
```
  The error log provides detailed troubleshooting methods and indicates that the ./target/NotExistFile.dll file does not exist or . NET SDK is not installed. The exit code is code 145.
- Ruby
  The following error message is reported if you set the instance startup command to ruby not_exist_file.rb:
```
Function instance exited unexpectedly(code 1, message:operation not permitted) with start command 'ruby not_exist_file.rb '.
Logs:Traceback (most recent call last):
ruby: No such file or directory -- not_exist_file.rb (LoadError)
```
  The error log message "No such file or directory -- not_exist_file.rb" indicates that the error is caused by the absence of the not_exist_file.rb file. The exit code is code 1, message:operation not permitted.
Invalid file format
```
Function instance exited unexpectedly(code 8, message:exec format error) with start command '/code/bootstrap '.
Logs:
```
A custom runtime runs on x86-64-based Linux. Make sure that your startup files are compatible with the system environment. If the startup command is a shell script, make sure that the file follows the Linux syntax and includes the #! line (shebang) at the beginning of the script. If the startup command is a binary executable file, make sure that it is an executable and linkable format (ELF) file that is compatible with Linux operating systems. The following section describes the file format errors.
- Shebang error of shell script in the startup command
  In most cases, 8 exec format error is reported as the exit code if the shell script lacks a valid shebang. To avoid the error, you must add a valid shebang to the first line of the shell script.
  If you want to use bash to run the script, you can add #!/usr/bin/env bash or #!/bin/bash to the first line of the file. We recommend that you use #!/usr/bin/env bash. By default, /bin/sh in a custom runtime is /bin/bash. Therefore, you can run the #!/usr/bin/env sh or #!/bin/sh command.
- Shell script in startup command in Windows syntax
  Run the following test script:
```
#!/usr/bin/env bash
node /code/index.js
```
  The following error message is returned:
```
Function instance exited unexpectedly(code 127, message:key has expired) with start command '/code/bootstrap '.
Logs:/usr/bin/env: 'bash\r': No such file or directory
```
  The error log message "bash\r" indicates that the bash command is followed by a carriage return character (\r). This is a characteristic of Windows file syntax, which uses \r\n to denote line breaks, whereas Unix files use \n. Therefore, it is likely that the file was created on a Windows system and follows Windows syntax.
  If you create your script on a Windows OS, you must convert it to a format compatible with UNIX OSs. You can run the dos2unix command in a Linux OS or use WebIDE of Function Compute to convert the script. For more information, see How to convert file formats by using WebIDE provided by Function Compute?
- A binary executable file used as the startup command
  If the startup command is an executable file, make sure that it is an ELF file, which is compatible with Linux OSs. For example, if you compile Golang code on a Mac that is equipped with M1 chips by using the default configuration GOOS=darwin GOARCH=arm64, the following error message is reported after the code is packaged, uploaded, and tested:
```
Function instance exited unexpectedly(code 8, message:exec format error) with start command './main '.
Logs:
```
  The instance exit code is 8 exec format error, which indicates that the file format is invalid. You must add GOOS=linux GOARCH=amd64 during the compilation. For more information, see Compile and deploy code packages.
  Expand to see how to check the format of an executable file
  - The following sample code shows an example on how to check the format of an executable file that is compiled by using GOOS=darwin GOARCH=arm64:
    $ file main main: Mach-O 64-bit arm64 executable, flags:<|DYLDLINK|PIE>
    In this example, the file format is Mach-O and the CPU architecture is arm64, which is incompatible with the underlying environment of custom runtimes.
  - The following sample code shows an example on how to check the format of an executable file that is compiled by using GOOS=linux GOARCH=amd64:
    $ file main main: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, Go BuildID=xxx, not stripped
    In this example, the file format is ELF and the CPU architecture is x86-64, which is compatible with the underlying environment of custom runtimes.
  Note
  Typically, executable files of Linux OSs are in the ELF format.
  Executable files of Mac OSs are in the Mach-O format.
  Executable files of Windows OSs are in the portable executable (PE) format.
Common exit codes
The following section describes other common exit codes.
- Exit Code 137
  The program receives SIGKILL and exceptionally exits. In most case, this issue is caused by OOMKilled(Out of Memory). In this case, you can upgrade the memory configuration for the function.

Additional information

If any error that is not listed in this topic occurs, see Custom Runtime FAQ.