What to do if instance user data for a Linux instance does not take effect and a "Failed to run module scripts-user" error appears

User-data scripts are directly run as shell scripts after the scripts are passed into Linux instances. User-data scripts have the following characteristics:

• The first line starts with a combination of a number sign and an exclamation point (#!).

• User-data scripts are run once only on the first boot of an instance.

Example:

#!/bin/sh
echo "Hello World. The time is now $(date -R)!" | tee /root/userdata_test.txt

cloud-config allows you to pre-configure specific services, such as Yellowdog Updater Modified (YUM) repository update, SSH key import, and dependency installation, for instances in a convenient manner. cloud-config data has the following characteristics:

• The first line is #cloud-config, and the header cannot include spaces.

• cloud-config data must follow the YAML syntax.

• The frequency at which the user data is run varies based on the configured module. For example, if you configure the Apt Configure module, the user data is run only once for each instance. If you configure the Bootcmd module, the user data is run each time the instance starts.

Example:

#cloud-config
apt:
 primary:
  - arches: [default]
    uri: https://us.archive.ubuntu.com/ubuntu/
    bootcmd:
     - echo "Hello World. The time is now $(date -R)!" | tee /root/userdata_test.txt

An include file contains one or more script links. Each line contains one script link. When an instance starts, cloud-init reads each script link and script content. If an error occurs when the content of a script is being read, the remaining scripts are not read. Include files have the following characteristics:

• The first line is #include, and the header cannot include spaces.

• Each script cannot exceed 16 KB in size before the script is encoded in Base64.

• The frequency at which the user data is run varies based on the script type and module type.

Example:

#include
https://ecs-image-test.oss-cn-hangzhou.aliyuncs.com/userdata/myscript.sh

If the user-data script, cloud-config data, or include file exceeds 16 KB in size, you can compress the user-data script, cloud-config data, or include file into gzip compressed content (.gz), create a link to the content, and then pass the link in an include file. cloud-init automatically decompresses the gzip compressed content. The result of running the decompressed content is the same as the result of running uncompressed content that is directly passed. Gzip compressed content has the following characteristics:

• The first line is #include, and the header cannot include spaces.

• The size of the gzip compressed content cannot exceed 16 KB before the content is encoded in Base64.

• The frequency at which the user data is run varies based on script type and module type.

Example:

#include
https://ecs-image-test.oss-cn-hangzhou.aliyuncs.com/userdata/myscript.gz

The content of upstart job scripts is stored in a file in the /etc/init directory. Upstart job scripts have the following characteristics:

• The first line is #upstart-job, and the header cannot include spaces.

• Upstart job scripts are run each time the instance starts.

Example:

#upstart-job
description "upstart test"
start on runlevel [2345] #Start at run levels 2, 3, 4, and 5.
stop on runlevel [!2345] #Stop at run levels other than 2, 3, 4, and 5.
exec echo "Hello World. The time is now $(date -R)!" | tee /root/output.txt