tencent cloud

Cloud-init

What is cloud-init?

Cloud-init is an open source tool that runs inside a CVM instance as a non-resident service. It is executed at startup and exits immediately after execution. It does not listen to any ports.
All the Linux public images of Tencent Cloud are pre-installed with the cloud-init service. You need to run the service as the root user because the service is mainly used for the initialization of CVM instances such as configuring DNS, hostname, and IP, and the execution of some custom scripts that users specify to be executed during the first boot when creating the CVM instances.

How do I check whether the cloud-init service inside a Linux instance is working properly?

Troubleshooting cloud-init service errors

Log in to a Linux instance using the standard login method (recommended). Then, run the following commands in sequence and observe whether an error is reported. If the execution result is displayed, the service is running normally. Otherwise, the cause of the error will be reported. You can troubleshoot the error accordingly.

Note

This step only applies to CVM instances created with public Linux images. If you installed cloud-init by yourself, adjust the commands according to the actual situation.

1. Delete the cloud-init cache directory.

   rm -rf /var/lib/cloud
   

2. Perform complete cloud-init initialization.

   /usr/bin/cloud-init init --local
   

3. Pull data from the configured data source.

   /usr/bin/cloud-init init
   

4. Cloud-init initialization involves multiple stages. To ensure sufficient dependency between the stages, config stage is specified for the cloud-init modules.

   /usr/bin/cloud-init modules --mode=config
   

5. Specify final stage for the cloud-init modules.

   /usr/bin/cloud-init modules --mode=final
   

What initialization operations does cloud-init perform on instances?

Tencent Cloud implements all instance initialization operations through cloud-init, ensuring the transparency of the operations inside an instance. The following briefly covers some initialization operations. For more details, see cloud-init documentation.

How can I fix issues related to cloud-init?

1. Error due to the unmounting of the cloud-init dependencies

• Problem description:
  When commands are used to check whether the cloud-init service is working properly, the following error is returned:

  Traceback (most recent call last):
  File "/usr/bin/cloud-init", line 5, in 
   ********
   raise DistributionNotFound(req)
  pkg_resources.DistributionNotFound: pyyaml
  

• Problem analysis:
  "pkg_resources.DistributionNotFound: xxxxx" indicates that the cloud-init dependencies have been uninstalled.

• Solution:

1. Reinstall the dependencies.
2. Follow Checking the operation of cloud-init to see if the error is returned again.

2. Error due to the modification of the default Python interpreter

• Problem description:
  An error is returned when cloud-init is run on startup.
• Problem analysis:
  When cloud-init is installed, Python 2 is used as the default Python interpreter, which means that symbolic links, /usr/bin/python and /bin/python, are linked to Python 2. Users may change the default Python interpreter to Python 3 inside the instance by directing the symbolic links, /usr/bin/python and /bin/python, to Python 3. Due to compatibility issues, an error will be returned when cloud-init is run on startup.
• Solution:

1. Modify the Python interpreter specified in the /usr/bin/cloud-init file by changing #/usr/bin/python or #/bin/python to #! user/bin/python.

   Note

   Do not use symbolic links. Point directly to a specific interpreter.

2. Follow Checking the operation of cloud-init to see if the error is returned again.

Cloudbase-Init

What is Cloudbase-Init?

Like cloud-init, Cloudbase-Init is a bridge by which you can communicate with Windows CVM instances. The Cloudbase-Init service is run when an instance boots up for the first time. The service will read the initialization configuration information of the instance and initialize it. Following operations such as resetting password and modifying IP addresses are also done via Cloudbase-Init.

How do I check whether the Cloudbase-Init service inside a Windows instance is working properly?

Troubleshooting cloudbase-init service errors

1. Log in to the instance.

   Note

   If you forget your password or fail to reset your password because of Cloudbase-Init service exceptions, you can reset your password by following step 2.

2. Open Control panel > Administrative tools > Services.
3. Find the cloudbase-init service, right-click it, and go to Properties.

• Check "Startup type" and make sure it is set to "Automatic". See the figure below.
  
• View "Logon identity" and ensure that "Local System account" is selected. See the figure below.
  
• Manually start the Cloudbase-Init service and see if any error is returned.
  If any error is returned, you need to fix the issue first and check whether you have installed any security software which may stop Cloudbase-Init from performing related operations.
  
• Open the registry, find all "LocalScriptsPlugin", and make sure its value is 2. See the figure below.
  
• Check whether CD-ROM loading is disabled. If there is an optical disc drive as shown in the figure below, it means that the loading has not been disabled; otherwise, it means that it has been disabled and needs to be enabled.
  

How do I fix common issues related to Cloudbase-Init?

Failed to reset password during initialization

• Possible reasons:
• The Cloudbase-Init account password is manually changed, which results in the failure to start the Cloudbase-Init service, which further led to the failure of operations such as resetting password during initialization.
• The Cloudbase-Init service is disabled, which led to the failure of operations such as resetting password during initialization.
• The security software installed stops the Cloudbase-Init service from resetting password so that the operation returns a successful result but actually failed.
• Solution:
  Follow the corresponding solution to each possible reason to fix the issue.

1. Change the Cloudbase-Init service to LocalSystem service. For details, see step 2 in Checking the operation of the Cloudbase-Init service.
2. Change the startup type of the Cloudbase-Init service to automatic. For details, see step 2 in Checking the operation of the Cloudbase-Init service.
3. Uninstall the security software involved or add the relevant operations of the Cloudbase-Init service to the white list of the security software.