如何在AWS中的自定义AMI上设置cloud-init？ （CentOS） [英] How do I set up cloud-init on custom AMIs in AWS? (CentOS)
问题描述
在AWS中为实例定义用户数据对于执行各种引导类型的操作非常有用。不幸的是，我不得不使用一个自定义的CentOS AMI，由于PCI原因，并非源于提供的AMI之一，因此cloud-init尚未安装和配置。我只是真的想要它设置一个主机名，并运行一个小的bash脚本。
Defining userdata for instances in AWS seems really useful for doing all kinds of bootstrap-type actions. Unfortunately, I have to use a custom CentOS AMI that didn't originate from one of the provided AMIs for PCI reasons, so cloud-init is not already installed and configured. I only really want it to set a hostname and run a small bash script. How do I get it working?
推荐答案
cloud-init是一个非常强大，但非常无文档的工具。即使它安装了，有很多模块默认活动，覆盖你可能已经定义在您的AMI的东西。以下是从头开始进行最小设置的说明：
cloud-init is a very powerful, but very undocumented tool. Even once it's installed, there are lot of modules active by default that overwrite things you may have already defined on your AMI. Here are instructions for a minimal setup from scratch:
-
从标准存储库安装cloud-init。如果您担心PCI，您可能不想使用AWS的自定义存储库。
Install cloud-init from a standard repository. If you're worried about PCI, you probably don't want to use AWS's custom repositories.
# rpm -Uvh https://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# yum install cloud-init
编辑 /etc/cloud/cloud.cfg ，一个yaml档案，组态。下面是每个模块的文档的最小配置。
Edit /etc/cloud/cloud.cfg, a yaml file, to reflect your desired configuration. Below is a minimal configuration with documentation for each module.
#If this is not explicitly false, cloud-init will change things so that root
#login via ssh is disabled. If you don't want it to do anything, set it false.
disable_root: false
#Set this if you want cloud-init to manage hostname. The current
#/etc/hosts file will be replaced with the one in /etc/cloud/templates.
manage_etc_hosts: true
#Since cloud-init runs at multiple stages of boot, this needs to be set so
#it can log in all of them to /var/log/cloud-init.
syslog_fix_perms: null
#This is the bit that makes userdata work. You need this to have userdata
#scripts be run by cloud-init.
datasource_list: [Ec2]
datasource:
Ec2:
metadata_urls: ['http://169.254.169.254']
#modules that run early in boot
cloud_init_modules:
- bootcmd #for running commands in pre-boot. Commands can be defined in cloud-config userdata.
- set-hostname #These 3 make hostname setting work
- update-hostname
- update-etc-hosts
#modules that run after boot
cloud_config_modules:
- runcmd #like bootcmd, but runs after boot. Use this instead of bootcmd unless you have a good reason for doing so.
#modules that run at some point after config is finished
cloud_final_modules:
- scripts-per-once #all of these run scripts at specific events. Like bootcmd, can be defined in cloud-config.
- scripts-per-boot
- scripts-per-instance
- scripts-user
- phone-home #if defined, can make a post request to a specified url when done booting
- final-message #if defined, can write a specified message to the log
- power-state-change #can trigger stuff based on power state changes
system_info:
#works because amazon's linux AMI is based on CentOS
distro: amazon
如果 /etc/cloud/cloud.cfg.d / 中有 defaults.cfg
要利用此配置，请为新实例定义以下userdata：
To take advantage of this configuration, define the following userdata for new instances:
#cloud-config
hostname: myhostname
fqdn: myhostname.mydomain.com
runcmd:
- echo "I did this thing post-boot"
- echo "I did this too"
bash脚本替换＃cloud-config 与＃！/ bin / bash 但如果你这样做，你应该从 cloud_init_modules 中删除所有与主机名相关的模块。
You can also simply run a bash script by replacing #cloud-config with #!/bin/bash and putting the bash script in the body, but if you do, you should remove all of the hostname-related modules from cloud_init_modules.
请注意， ，cloud-init能够管理用户，ssh密钥，挂载点等。请参阅下面的参考文档，了解有关这些特定功能的更多文档。
Note that this is a minimal configuration, and cloud-init is capable of managing users, ssh keys, mount points, etc. Look at the references below for more documentation on those specific features.
似乎cloud-init基于指定的模块做的东西。一些模块，如disable-ec2-metadata，只是简单地通过指定。其他的，像runcmd，只有在cloud.cfg或cloud-config userdata中指定参数时才做。下面的大多数文档只告诉你什么参数是可能的每个模块，而不是模块被称为，但默认cloud.cfg应该有一个完整的模块列表开始。
In general, it seems that cloud-init does stuff based on the modules specified. Some modules, like "disable-ec2-metadata", do stuff simply by being specified. Others, like "runcmd", only do stuff if their parameters are specified, either in cloud.cfg, or in cloud-config userdata. Most of the documentation below only tell you what parameters are possible for each module, not what the module is called, but the default cloud.cfg should have a complete module list to begin with. The best way I've found to disable a module is simply to remove it from the list.
在某些情况下，rhel可能更适合distro标签比亚马逊。我没有真正想出什么时候。
In some cases, "rhel" may work better for the "distro" tag than "amazon". I haven't really figured out when.
- 如何安装cloud-init：http：//web.archive.org/web/20140925130743/http：//docs.openstack.org/grizzly/openstack-image/content/centos- image.html
- 模组参考（不完整）： http://cloudinit.readthedocs.org/en/latest/topics/examples.html
- 模组参考（不完整）： https://github.com/number5/cloud-init/blob/master/doc/examples/cloud-config。 txt
- 一般设定说明：http://web.archive.org/web/20150110200930/http://www.scalehorizontally.com/2013/02/24/introduction-to-cloud- init
- 主机名管理： http://web.archive.org/web/20140805225413/http://docs.openstack.org/user-guide/content/user-data.html
- How to install cloud-init: http://web.archive.org/web/20140925130743/http://docs.openstack.org/grizzly/openstack-image/content/centos-image.html
- Modules reference (incomplete): http://cloudinit.readthedocs.org/en/latest/topics/examples.html
- Modules reference (incomplete): https://github.com/number5/cloud-init/blob/master/doc/examples/cloud-config.txt
- General setup instructions: http://web.archive.org/web/20150110200930/http://www.scalehorizontally.com/2013/02/24/introduction-to-cloud-init
- Hostname management: http://web.archive.org/web/20140805225413/http://docs.openstack.org/user-guide/content/user-data.html
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