User-data scripts is not running on my custom AMI, but working in standard Amazon linux

Question

I searched a lot of topic about "user-data script is not working" in these few days, but until now, I haven't gotten any idea about my case yet, please help me to figure out what happened, thanks a lot!

According to AWS User-data explanation:

When you launch an instance in Amazon EC2, you have the option of passing user data to the instance that can be used to perform common automated configuration tasks and even run scripts after the instance starts.

So I tried to pass my own user-data when instance launch, this is my user-data:

\#!/bin/bash

echo 'test' > /home/ec2-user/user-script-output.txt

But there is no file in this path: /home/ec2-user/user-script-output.txt

I checked /var/lib/cloud/instance/user-data.txt, the file is exist and same as my user-data script.

Also I checked the log in /var/log/cloud-init.log, there is no error message.

But the user-data script is working if I launch an new instance with Amazon linux(2014.09.01), but I'm not sure what difference between my AMI (based on Amazon linux) and Amazon linux.

The only different part I saw is if I run this script:

sudo yum list installed | grep cloud-init

My AMI:

cloud-init.noarch 0.7.2-8.33.amzn1 @amzn-main

Amazon linux:

cloud-init.noarch 0.7.2-8.33.amzn1 installed

I'm not sure this is the reason?

If you need more information, I'm glad to provide, please let me know what happened in my own AMI and how to fix it?

many thanks

Update

Just found an answer from this post,

If I add #cloud-boothook in the top of user-data file, it works!

#cloud-boothook
#!/bin/bash
echo 'test' > /home/ec2-user/user-script-output.txt

But still not sure why.

Solution 1

User_data is run only at the first start up. As your image is a custom one, I suppose it have already been started once and so user_data is desactivated.

For windows, it can be done by checking a box in Ec2 Services Properties. I'm looking at the moment how to do that in an automated way at the end of the custom image creation.

For linux, I suppose the mechanism is the same, and user_data needs to be re-activated on your custom image.

The #cloud-boothook make it works because it changes the script from a user_data mechanism to a cloud-boothook one that runs on each start.

---

EDIT :

Here is the code to reactivate start on windows using powershell:

$configFile = "C:\\Program Files\\Amazon\\Ec2ConfigService\\Settings\\Config.xml"
[xml] $xdoc = get-content $configFile
$xdoc.SelectNodes("//Plugin") |?{ $_.Name -eq "Ec2HandleUserData"} |%{ $_.State = "Enabled" }
$xdoc.SelectNodes("//Plugin") |?{ $_.Name -eq "Ec2SetComputerName"} |%{ $_.State = "Enabled" }
$xdoc.OuterXml | Out-File -Encoding UTF8 $configFile

$configFile = "C:\\Program Files\\Amazon\\Ec2ConfigService\\Settings\\BundleConfig.xml"
[xml] $xdoc = get-content $configFile
$xdoc.SelectNodes("//Property") |?{ $_.Name -eq "AutoSysprep"} |%{ $_.Value = "Yes" }
$xdoc.OuterXml | Out-File -Encoding UTF8 $configFile

(I know the question focus linux, but it could help others ...)

Solution 2

As I tested, there were some bootstrap data in /var/lib/cloud directory. After I cleared that directory, User Data script worked normally.

rm -rf /var/lib/cloud/*

Solution 3

I have also faced the same issue on Ubuntu 16.04 hvm AMI. I have raised the issue to AWS support but still I couldn't find exact reason/bug which affects it.

But still I have something which might help you.

Before taking AMI remove /var/lib/cloud directory (each time). Then while creating Image, set it to no-reboot.

If these things still ain't working, you can test it further by forcing user-data to run manually. Also tailf /var/log/cloud-init-output.log for cloud-init status. It should end with something like modules:final to make your user-data run. It should not stuck on modules:config.

sudo rm -rf /var/lib/cloud/* sudo cloud-init init sudo cloud-init modules -m final

I don't have much idea whether above commands will work on CentOS or not. I have tested it on Ubuntu.

In my case, I have also tried removing /var/lib/cloud directory, but still it failed to execute user-data in our scenario. But I have came up with different solution for it. What we have did is we have created script with above commands and made that script to run while system boots.

I have added below line in /etc/rc.local to make it happen.

sudo bash /home/ubuntu/force-user-data.sh || exit 1

But here is the catch, it will execute the script on each boot so which will make your user-data to run on every single boot, just like #cloud-boothook. No worries, you can just tweak it by just removing the force-user-data.sh itself at the end. So your force-user-data.sh will look something like

#!/bin/bash sudo rm -rf /var/lib/cloud/* sudo cloud-init init sudo cloud-init modules -m final sudo rm -f /home/ubuntu/force-user-data.sh exit 0

I will appreciate if someone can put some lights on why it is unable to execute the user-data.

Solution 4

this is the answer as an example: ensure that you have in the headline only #!/bin/bash

#!/bin/bash
yum update -y
yum install httpd mod_ssl
service httpd start
chkconfig httpd on

Solution 5

I was having a lot of trouble with this. I'll provide detailed walk-though.

My added wrinkle is that I'm using terraform to instantiate the hosts via a launch configuration and autoscaling group.

I could NOT get it to work by adding the script inline in lc.tf

user_data                   = DATA <<
"
#cloud-boothook
#!/bin/bash
echo 'some crap'\'
"
DATA

I could fetch it from user data,

wget http://169.254.169.254/latest/user-data

but noticed I was getting it with the quotes still in it.

This is how I got it to work: I moved to pulling it from a template instead since what you see is what you get.

user_data                   = "${data.template_file.bootscript.rendered}"

This means I also need to declare my template file like so:

data "template_file" "bootscript" {
  template = "${file("bootscript.tpl")}"

}

But I was still getting an error in the cloud init logs /var/log/cloud-init.log [WARNING]: Unhandled non-multipart (text/x-not-multipart) userdata: 'Content-Type: text/cloud...'

Then I found this article about user data formatting user That makes sense, if user-data can come in multiple parts, maybe cloud-init needs cloud-init commands in one place and the script in the other.

So my bootscript.tpl looks like this:

Content-Type: multipart/mixed; boundary="//"
MIME-Version: 1.0

--//
Content-Type: text/cloud-config; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cloud-config.txt"

#cloud-config
cloud_final_modules:
- [scripts-user, always]

--//
Content-Type: text/x-shellscript; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="userdata.txt"

#!/bin/bash
echo "some crap"
--//

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Comments

[Kai]

Thanks for answer, sorry about that, the /home/ec2-user/user-script/output.txt is typo, already fixed it, for now I still don't know why it doesn't work if I remove #cloud-boothook, still trying to figure out

[jouell]

amazing. you saved me lots of time!

[Hanno Kolvenbach]

This worked for me on an Ubuntu, however I needed to run sudo rm -r /var/lib/cloud/instances because instances is a directory.

[Elliott B]

Can you explain what this is supposed to do?