Scenario

Cloud-init allows you to customize configurations during the first initialization of an instance. If the imported image does not have the cloud-init service installed, instances booted through the image cannot be initialized properly. As a result, the image fails to be imported. This document describes how to install the cloud-init service.
You can install cloud-init in two ways:

• Manually downloading the cloud-init source package
• Using the cloud-init package from the software source

Notes

Before importing a Linux image, ensure that you have properly installed the cloud-init service in the image.

Prerequisites

A server with the cloud-init service installed can correctly access external networks.

Directions

Manually downloading the cloud-init source package

Downloading the cloud-init source package

• cloud-init-17.1 is the version best compatible with Tencent Cloud. It ensures that all configuration items of CVMs created through the image can be initialized properly. We recommend that you install cloud-init-17.1.tar.gz. You can also click here to download other versions. This document uses cloud-init-17.1 as an example.
• If the installation fails, manually download the green cloud-init package to install the service.

Run the following command to download the cloud-init source package:

wget https://launchpad.net/cloud-init/trunk/17.1/+download/cloud-init-17.1.tar.gz

Installing cloud-init

1. Run the following command to decompress the cloud-init installation package:

   If you are using the Ubuntu operating system, run this command with the root account.

   tar -zxvf cloud-init-17.1.tar.gz 

2. Run the following command to enter the decompressed cloud-init installation package directory, that is, the cloud-init-17.1 directory:

   cd cloud-init-17.1

3. Install Python-pip according to the operating system version.
   • For CentOS 6 or 7, run the following command:

     yum install python-pip -y

   • For Ubuntu, run the following command:

     apt-get install python-pip -y

4. Run the following command to install dependencies:

   Python 2.6 is not supported when cloud-init uses requests 2.20.0. If the Python interpreter installed in the image environment is Python 2.6 or earlier, run pip install 'requests<2.20.0' to install requests 2.20.0 or later before installing the cloud-init dependencies.

   pip install -r requirements.txt

5. Install the cloud-utils component according to the operating system version.
   • For CentOS 6, run the following command:

     yum install cloud-utils-growpart dracut-modules-growroot -y
     dracut -f

   • For CentOS 7, run the following command:

     yum install cloud-utils-growpart -y

   • For Ubuntu, run the following command:

     apt-get install cloud-guest-utils -y

6. Run the following commands to install cloud-init:

   python setup.py build
   python setup.py install --init-system systemd

   -- Optional parameters of init-system include systemd, sysvinit, sysvinit_deb, sysvinit_freebsd, sysvinit_openrc, sysvinit_suse, and upstart [default: None]. Configure parameters based on the auto-start service management method of the operating system. If incorrect parameters are configured, the cloud-init service cannot automatically start upon system startup. This document uses the systemd self-start service management method as an example.

Modifying the cloud-init configuration file

1. Download cloud.cfg for your operating system.
   • Click here to download cloud.cfg for Ubuntu.
   • Click here to download cloud.cfg for CentOS.
2. Replace the content of /etc/cloud/cloud.cfg with that of the downloaded cloud.cfg file.

Adding a syslog user

Run the following command to add a syslog user:

useradd syslog

Setting the cloud-init service to automatically start upon system startup

• If your operating system uses systemd to manage self-start services, run the following commands.
  1. Run the following command in Ubuntu or Debian:

     ln -s /usr/local/bin/cloud-init /usr/bin/cloud-init 

  2. Run the following commands in all operating systems:

     systemctl enable cloud-init-local.service 
     systemctl start cloud-init-local.service
     systemctl enable cloud-init.service
     systemctl start cloud-init.service
     systemctl enable cloud-config.service
     systemctl start cloud-config.service
     systemctl enable cloud-final.service
     systemctl start cloud-final.service
     systemctl status cloud-init-local.service
     systemctl status cloud-init.service
     systemctl status cloud-config.service
     systemctl status cloud-final.service

  3. Run the following command in CentOS or Redhat.
     Replace the content of /lib/systemd/system/cloud-init-local.service with the following:

     [Unit]
     Description=Initial cloud-init job (pre-networking)
     Wants=network-pre.target
     After=systemd-remount-fs.service
     Before=NetworkManager.service
     Before=network-pre.target
     Before=shutdown.target
     Conflicts=shutdown.target
     RequiresMountsFor=/var/lib/cloud
     [Service]
     Type=oneshot
     ExecStart=/usr/bin/cloud-init init --local
     ExecStart=/bin/touch /run/cloud-init/network-config-ready
     RemainAfterExit=yes
     TimeoutSec=0
     # Output needs to appear in instance console output
     StandardOutput=journal+console
     [Install]
     WantedBy=cloud-init.target

     Replace the content of /lib/systemd/system/cloud-init.service with the following:

     [Unit]
     Description=Initial cloud-init job (metadata service crawler)
     Wants=cloud-init-local.service
     Wants=sshd-keygen.service
     Wants=sshd.service
     After=cloud-init-local.service
     After=systemd-networkd-wait-online.service
     After=networking.service
     After=systemd-hostnamed.service
     Before=network-online.target
     Before=sshd-keygen.service
     Before=sshd.service
     Before=systemd-user-sessions.service
     Conflicts=shutdown.target
     [Service]
     Type=oneshot
     ExecStart=/usr/bin/cloud-init init
     RemainAfterExit=yes
     TimeoutSec=0
     # Output needs to appear in instance console output
     StandardOutput=journal+console
     [Install]
     WantedBy=cloud-init.target

• If your operating system uses sysvinit to manage self-start services, run the following commands:

  chkconfig --add cloud-init-local
  chkconfig --add cloud-init
  chkconfig --add cloud-config
  chkconfig --add cloud-final
  chkconfig cloud-init-local on 
  chkconfig cloud-init on 
  chkconfig cloud-config on 
  chkconfig cloud-final on 

Using the cloud-init package from the software source

Installing cloud-init

Run the following command to install cloud-init:

apt-get/yum install cloud-init

By default, the cloud-init version installed by running apt-get or yum is the default cloud-init version in the software source configured for the operating system. Some configuration items of instances created by using the image whose cloud-init is installed this way may not be initialized as expected. Therefore, we recommend that you install the service by manually downloading the cloud-init source package.

Modifying the cloud-init configuration file

1. Download cloud.cfg for your operating system.
   • Click here to download cloud.cfg for Ubuntu.
   • Click here to download cloud.cfg for CentOS.
2. Replace the content of /etc/cloud/cloud.cfg with that of the downloaded cloud.cfg file.

Relevant Operations

Do not restart the server after performing the following operations. Otherwise, you need to perform them again.

1. Run the following commands to check whether the cloud-init configuration is successful:

   cloud-init init --local
   rm -rf /var/lib/cloud

2. Run the following command in Ubuntu or Debian:

   rm -rf /etc/network/interfaces.d/50-cloud-init.cfg

3. For Ubuntu or Debian, replace the content of /etc/network/interfaces with the following:

   # This file describes the network interfaces available on your system
   # and how to activate them. For more information, see interfaces(5).
   source /etc/network/interfaces.d/*

Appendix

Manually downloading the green cloud-init package

If the cloud-init service fails to be installed by manually downloading the cloud-init source package, complete the following steps to install cloud-init:

1. Click here to obtain the green cloud-init package.
2. Run the following command to decompress the green cloud-init package:

   tar xvf greeninit-x64-beta.tgz 

3. Run the following command to enter the decompressed green cloud-init package directory, that is, the greeninit directory:

   cd greeninit

4. Run the following command to install cloud-init:

   sh install.sh