Install Cloud-Init on Linux

Introduction

Cloud-init enables you to customize configuration during the first initialization of an instance. If the imported image is not installed with the cloud-init service, instances booted with the image will not be initialized properly, which will result in image import failures. This document describes how to install the cloud-init service.
You can install cloud-init in two ways:

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

Notes

Before importing a Linux image, please make sure you have properly installed the cloud-init service in your image.

Prerequisites

Servers installed with the cloud-init service can visit external IPs.

Directions

Manually downloading cloud-init source package

Downloading the cloud-init source package

The cloud-init-17.1 version is the most compatible with Tencent Cloud, which can ensure that all configuration items of the CVMs created with the image can be initialized properly. It is recommended to 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.

Execute 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. Execute the following command to decompress the cloud-init installation package.

   If your operating system is Ubuntu, please use the root account.

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

2. Execute the following command to enter the directory of the decompressed package, i.e., the cloud-init-17.1 directory.

   cd cloud-init-17.1

3. Install Python-pip according to your OS version.
   • For CentOS 6/7, execute the following command:

     yum install python-pip -y

   • For Ubuntu, execute the following command:

     apt-get install python-pip -y

4. Execute 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 below, please execute pip install 'requests<2.20.0' to install requests version below 2.20.0 before installing the cloud-init dependencies.

   pip install -r requirements.txt

5. Install the cloud-utils components according to your OS version.
   • For CentOS 6, execute the following command:

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

   • For CentOS 7, execute the following command:

     yum install cloud-utils-growpart -y

   • For Ubuntu, execute the following command:

     apt-get install cloud-guest-utils -y

6. Execute the following command to install cloud-init.

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

   Optional parameters for --init-system include: (systemd, sysvinit, sysvinit_deb, sysvinit_freebsd, sysvinit_openrc, sysvinit_suse, upstart) [default: None]. Make a selection based on the current method of managing auto-start services of your OS. If you select a wrong one, the cloud-init service will not auto-start on boot. This document uses the systemd auto-start service manager 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 in /etc/cloud/cloud.cfg with the content of the downloaded cloud.cfg file.

Adding syslog user

Execute the following command to add a syslog user.

useradd syslog

Configuring the auto-start of the cloud-init service on boot

• If your operating system uses systemd to manage auto-start services, execute the following commands to make the configuration.
  1. Execute the following command in Ubuntu or Debian.

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

  2. Execute 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. Execute the following command in CentOS or Redhat.
     Replace the content in /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 in /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 auto-start services, execute the following commands to make the configuration.

  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

Execute the following command to install cloud-init.

apt-get/yum install cloud-init

By default, the cloud-init version installed via apt-get or yum is the default cloud-init version in the software source configured for the current operating system. In the instances created with images whose cloud-init is installed this way, some configuration items may not be initialized as expected. It is recommended to install the service by manually downloading 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 in /etc/cloud/cloud.cfg with the content of the downloaded cloud.cfg file.

Related Operations

Please do not restart the server after you finish the following operations. Otherwise, you will need to perform the following operations again.

1. Execute the following command to see if cloud-init has been configured successfully.

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

2. Execute the following command in Ubuntu or Debian.

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

3. For Ubuntu or Debian, you need to modify the content of /etc/network/interfaces to 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/*