Vagrant Rsync Error before provisioning

Question

So I'm having some adventures with the vagrant-aws plugin, and I'm now stuck on the issue of syncing folders. This is necessary to provision the machines, which is the ultimate goal. However, running vagrant provision on my machine yields

[root@vagrant-puppet-minimal vagrant]# vagrant provision
[default] Rsyncing folder: /home/vagrant/ => /vagrant
The following SSH command responded with a non-zero exit status.
Vagrant assumes that this means the command failed! 
mkdir -p '/vagrant'

I'm almost positive the error is caused because ssh-ing manually and running that command yields 'permission denied' (obviously, a non-root user is trying to make a directory in the root directory). I tried ssh-ing as root but it seems like bad practice. (and amazon doesn't like it) How can I change the folder to be rsynced with vagrant-aws? I can't seem to find the setting for that. Thanks!

Answer 1

Most likely you are running into the known vagrant-aws issue #72: Failing with EC2 Amazon Linux Images.

Edit 3 (Feb 2014): Vagrant 1.4.0 (released Dec 2013) and later versions now support the boolean configuration parameter config.ssh.pty. Set the parameter to true to force Vagrant to use a PTY for provisioning. Vagrant creator Mitchell Hashimoto points out that you must not set config.ssh.pty on the global config, you must set it on the node config directly.

This new setting should fix the problem, and you shouldn't need the workarounds listed below anymore. (But note that I haven't tested it myself yet.) See Vagrant's CHANGELOG for details -- unfortunately the config.ssh.pty option is not yet documented under SSH Settings in the Vagrant docs.

Edit 2: Bad news. It looks as if even a boothook will not be "faster" to run (to update /etc/sudoers.d/ for !requiretty) than Vagrant is trying to rsync. During my testing today I started seeing sporadic "mkdir -p /vagrant" errors again when running vagrant up --no-provision. So we're back to the previous point where the most reliable fix seems to be a custom AMI image that already includes the applied patch to /etc/sudoers.d.

Edit: Looks like I found a more reliable way to fix the problem. Use a boothook to perform the fix. I manually confirmed that a script passed as a boothook is executed before Vagrant's rsync phase starts. So far it has been working reliably for me, and I don't need to create a custom AMI image.

Extra tip: And if you are relying on cloud-config, too, you can create a Mime Multi Part Archive to combine the boothook and the cloud-config. You can get the latest version of the write-mime-multipart helper script from GitHub.

Usage sketch:

$ cd /tmp
$ wget https://raw.github.com/lovelysystems/cloud-init/master/tools/write-mime-multipart
$ chmod +x write-mime-multipart
$ cat boothook.sh
#!/bin/bash
SUDOERS_FILE=/etc/sudoers.d/999-vagrant-cloud-init-requiretty
echo "Defaults:ec2-user !requiretty" > $SUDOERS_FILE
echo "Defaults:root !requiretty" >> $SUDOERS_FILE
chmod 440 $SUDOERS_FILE

$ cat cloud-config
#cloud-config

packages:
  - puppet
  - git
  - python-boto

$ ./write-mime-multipart boothook.sh cloud-config > combined.txt

You can then pass the contents of 'combined.txt' to aws.user_data, for instance via:

aws.user_data = File.read("/tmp/combined.txt")

Sorry for not mentioning this earlier, but I am literally troubleshooting this right now myself. :)

Original answer (see above for a better approach)

TL;DR: The most reliable fix is to "patch" a stock Amazon Linux AMI image, save it and then use the customized AMI image in your Vagrantfile. See below for details.

Background

A potential workaround is described (and linked in the bug report above) at https://github.com/mitchellh/vagrant-aws/pull/70/files. In a nutshell, add the following to your Vagrantfile:

aws.user_data = "#!/bin/bash\necho 'Defaults:ec2-user !requiretty' > /etc/sudoers.d/999-vagrant-cloud-init-requiretty && chmod 440 /etc/sudoers.d/999-vagrant-cloud-init-requiretty\nyum install -y puppet\n"

Most importantly this will configure the OS to not require a tty for user ec2-user, which seems to be the root of the problem. I /think/ that the additional installation of the puppet package is not required for the actual fix (although Vagrant may use Puppet for provisioning the machine later, depending on how you configured Vagrant).

My experience with the described workaround

I have tried this workaround but Vagrant still occasionally fails with the same error. It might be a "race condition" where Vagrant happens to run its rsync phase faster than cloud-init (which is what aws.user_data is passing information to) can prepare the workaround for #72 on the machine for Vagrant. If Vagrant is faster you will see the same error; if cloud-init is faster it works.

What will work (but requires more effort on your side)

What definitely works is to run the command on a stock Amazon Linux AMI image, and then save the modified image (= create an image snapshot) as a custom AMI image of yours.

# Start an EC2 instance with a stock Amazon Linux AMI image and ssh-connect to it
$ sudo su - root
$ echo 'Defaults:ec2-user !requiretty' > /etc/sudoers.d/999-vagrant-cloud-init-requiretty
$ chmod 440 /etc/sudoers.d/999-vagrant-cloud-init-requiretty

# Note: Installing puppet is mentioned in the #72 bug report but I /think/ you do not need it
#       to fix the described Vagrant problem.
$ yum install -y puppet

You must then use this custom AMI image in your Vagrantfile instead of the stock Amazon one. The obvious drawback is that you are not using a stock Amazon AMI image anymore -- whether this is a concern for you or not depends on your requirements.

What I tried but didn't work out

For the record: I also tried to pass a cloud-config to aws.user_data that included a bootcmd to set !requiretty in the same way as the embedded shell script above. According to the cloud-init docs bootcmd is run "very early" in the startup cycle for an EC2 instance -- the idea being that bootcmd instructions would be run earlier than Vagrant would try to run its rsync phase. But unfortunately I discovered that the bootcmd feature is not implemented in the outdated cloud-init version of current Amazon's Linux AMIs (e.g. ami-05355a6c has cloud-init 0.5.15-69.amzn1 but bootcmd was only introduced in 0.6.1).