Vagrant vsftp and other tricks

As I previously wrote, I’ve been busy with Vagrant on Fedora with libvirt, and have even been submitting, patches and issues! (This “closed” issue needs solving!) Here are some of the tricks that I’ve used while hacking away.

Default provider:

I should have mentioned this in my earlier article but I forgot: If you’re always using the same provider, you might want to set it as the default. In my case I’m using vagrant-libvirt. To do so, add the following to your .bashrc:

export VAGRANT_DEFAULT_PROVIDER=libvirt

This helps you avoid having to add --provider=libvirt to all of your vagrant commands.

Aliases:

All good hackers use shell (in my case bash) aliases to make their lives easier. I normally keep all my aliases in .bash_aliases, but I’ve grouped them together with some other vagrant related items in my .bashrc:

alias vp='vagrant provision'
alias vup='vagrant up'
alias vssh='vagrant ssh'
alias vdestroy='vagrant destroy'

Bash functions:

There are some things aliases just can’t do. For those situations, a bash function might be most appropriate. These go inside your .bashrc file. I’d like to share two with you:

Vagrant logging:

Sometimes it’s useful to get more information from the vagrant command that is running. To do this, you can set the VAGRANT_LOG environment variable to info, or debug.

function vlog {
	VAGRANT_LOG=info vagrant "$@" 2> vagrant.log
}

This is usually helpful for debugging a vagrant issue. When you use the vlog command, it works exactly as the normal vagrant command, but it spits out a vagrant.log logfile into the working directory.

Vagrant sftp:

Vagrant provides an ssh command, but it doesn’t offer an sftp command. The sftp tool is fantastically useful when you want to quickly push or pull a file over ssh. First I’ll show you the code so that you can practice reading bash:

# vagrant sftp
function vsftp {
	[ "$1" = '' ] || [ "$2" != '' ] && echo "Usage: vsftp  - vagrant sftp" 1>&2 && return 1
	wd=`pwd`		# save wd, then find the Vagrant project
	while [ "`pwd`" != '/' ] && [ ! -e "`pwd`/Vagrantfile" ] && [ ! -d "`pwd`/.vagrant/" ]; do
		#echo "pwd is `pwd`"
		cd ..
	done
	pwd=`pwd`
	cd $wd
	if [ ! -e "$pwd/Vagrantfile" ] || [ ! -d "$pwd/.vagrant/" ]; then
		echo 'Vagrant project not found!' 1>&2 && return 2
	fi

	d="$pwd/.ssh"
	f="$d/$1.config"

	# if mtime of $f is > than 5 minutes (5 * 60 seconds), re-generate...
	if [ `date -d "now - $(stat -c '%Y' "$f" 2> /dev/null) seconds" +%s` -gt 300 ]; then
		mkdir -p "$d"
		# we cache the lookup because this command is slow...
		vagrant ssh-config "$1" > "$f" || rm "$f"
	fi
	[ -e "$f" ] && sftp -F "$f" "$1"
}

This vsftp command will work from anywhere in the vagrant project root directory or deeper. It does this by first searching upwards until it gets to that directory. When it finds it, it creates a .ssh/ directory there, and stores the proper ssh_config stubs needed for sftp to find the machines. Then the sftp -F command runs, connecting you to your guest machine.

You’ll notice that the first time you connect takes longer than the second time. This is because the vsftp function caches the ssh_config file store operation. You might want to set a different timeout, or disable it altogether. I should also mention that this script searches for a Vagrantfile and .vagrant/ directory to identify the project root. If there is a more “correct” method, please let me know.

I’m particularly proud of this because it was a fun (and useful) hack. This function, and all the above .bashrc material is available here as an easy download.

NFS folder syncing/mounting:

The vagrant-libvirt provider supports one way folder “synchronization” with rsync, and NFS mounting if you want two-way synchronization. I would love if libvirt/vagrant-libvirt had support for real folder sharing via QEMU guest agent and/or 9p. Getting it to work wasn’t trivial. Here’s what I had to do:

Vagrantfile:

Define your “synced_folder” so that you add the :mount_options array:

config.vm.synced_folder "nfs/", "/tmp/nfs", :nfs => true, :mount_options => ['rw', 'vers=3', 'tcp']

When you specify anything in the :mount_options array, it erases all the defaults. The defaults are: vers=3,udp,rw. Obviously, choose your own directory paths! I’d rather see this use NFSv4, but it would have taken slightly more fighting. Please become a warrior today!

Firewall:

Firewalling is not automatic. To work around this, you’ll need to run the following commands before you use your NFS mount:

# systemctl restart nfs-server # this as root, the rest will prompt
$ firewall-cmd --permanent --zone public --add-service mountd
$ firewall-cmd --permanent --zone public --add-service rpc-bind
$ firewall-cmd --permanent --zone public --add-service nfs
$ firewall-cmd --reload

You should only have to do this once, but possibly each reboot. If you like, you can patch those commands to run at the top of your Vagrantfile. If you can help fix this issue permanently, the bug is here.

Sudo:

The use of sudo to automatically edit /etc/exports is a neat trick, but it can cause some problems:

1. It is often not needed
2. It annoyingly prompts you
3. It can bork your stdin

You get internet karma from me if you can help permanently solve any of those three problems.

Package caching:

As part of my deployments, Puppet installs a lot of packages. Repeatedly hitting a public mirror isn’t a very friendly thing to do, it wastes bandwidth, and it’s slower than having the packages locally! Setting up a proper mirror is a nice solution, but it comes with a management overhead. There is really only one piece of software that manages repositories properly, but using pulp has its own overhead, and is beyond the scope of this article. Because we’re not using our own local mirror, this won’t allow you to work entirely offline, as the metadata still needs to get downloaded from the net.

Installation:

As an interim solution, we can use vagrant-cachier. This plugin adds synced_folder‘s to the apt/yum cache directories. Sneaky! Since this requires two-way sync, you’ll need to get NFS folder syncing/mounting working first. Luckily, I’ve already taught you that!

To pass the right options through to vagrant-cachier, you’ll need this patch. I’d recommend first installing the plugin with:

$ vagrant plugin install vagrant-cachier

and then patching your vagrant-cachier manually. On my machine, the file to patch is found at:

~/.vagrant.d/gems/gems/vagrant-cachier-0.5.0/lib/vagrant-cachier/provision_ext.rb

Vagrantfile:

Here’s what I put in my Vagrantfile:

# NOTE: this doesn't cache metadata, full offline operation not possible
config.cache.auto_detect = true
config.cache.enable :yum		# choose :yum or :apt
if not ARGV.include?('--no-parallel')	# when running in parallel,
	config.cache.scope = :machine	# use the per machine cache
end
config.cache.enable_nfs = true	# sets nfs => true on the synced_folder
# the nolock option is required, otherwise the NFSv3 client will try to
# access the NLM sideband protocol to lock files needed for /var/cache/
# all of this can be avoided by using NFSv4 everywhere. die NFSv3, die!
config.cache.mount_options = ['rw', 'vers=3', 'tcp', 'nolock']

Since multiple package managers operating on the same cache can cause locking issues, this plugin lets you decide if you want a shared cache for all machines, or if you want separate caches. I know that when I use the --no-parallel option it’s safe (enough) to use a common cache because Puppet does all the package installations, and they all happen during each of their first provisioning runs which are themselves sequential.

This isn’t perfect, it’s a hack, but hacks are fun, and in this case, very useful. If things really go wrong, it’s easy to rebuild everything! I still think a few sneaky bugs remain in vagrant-cachier with libvirt, so please find, report, and patch them if you can, although it might be NFS that’s responsible.

Puppet integration:

Integration with Puppet makes this all worthwhile. There are two scenarios:

1. You’re using a puppetmaster, and you care about things like exported resources and multi-machine systems.
2. You don’t have a puppetmaster, and you’re running standalone “single machine” code.

The correct answer is #1. Standalone Puppet code is bad for a few reasons:

1. It neglects the multi-machine nature of servers, and software.
2. You’re not able to use useful features like exported resources.
3. It’s easy to (unknowingly) write code that won’t work with a puppetmaster.

If you’d like to see some code which was intentionally written to only work without a puppetmaster (and the puppetmaster friendly equivalent) have a look at my Pushing Puppet material.

There is one good reason for standalone Puppet code, and that is: bootstrapping. In particular, bootstrapping the Puppet server.

DNS:

You need some sort of working DNS setup for this to function properly. Whether that involves hacking up your /etc/hosts files, using one of the vagrant DNS plugins, or running dnsmasq/bind is up to you. I haven’t found an elegant solution yet, hopefully not telling you what I’ve done will push you to come up with something awesome!

The :puppet_server provisioner:

This is the vagrant (puppet agent) provisioner that lets you talk to a puppet server. Here’s my config:

vm.vm.provision :puppet_server do |puppet|
	puppet.puppet_server = 'puppet'
	puppet.options = '--test'    # see the output
end

I’ve added the --test option so that I can see the output go by in my console. I’ve also disabled the puppet service on boot in my base machine image, so that it doesn’t run before I get the chance to watch it. If your base image already has the puppet service running on boot, you can disable it with a shell provisioner. That’s it!

The :puppet provisioner:

This is the standalone vagrant (puppet apply) provisioner. It seems to get misused quite a lot! As I mentioned, I’m only using it to bootstrap my puppet server. That’s why it’s a useful provisioner. Here’s my config:

vm.vm.provision :puppet do |puppet|
	puppet.module_path = 'puppet/modules'
	puppet.manifests_path = 'puppet/manifests'
	puppet.manifest_file = 'site.pp'
	# custom fact
	puppet.facter = {
		'vagrant' => '1',
	}
end

The puppet/{modules,manifests} directories should exist in your project root. I keep the puppet/modules/ directory fresh with a make script that rsync’s code in from my git directories, but that’s purely a personal choice. I added the custom fact as an example. All that’s left is for this code to build a puppetmaster!

Building a puppetmaster:

Here’s my site.pp:

node puppet {	# puppetmaster

	class { '::puppet::server':
		pluginsync => true,	# do we want to enable pluginsync?
		storeconfigs => true,	# do we want to enable storeconfigs?
		autosign => ['*'],	# NOTE: this is a temporary solution
		#repo => true,		# automatic repos (DIY for now)
		start => true,
	}

	class { '::puppet::deploy':
		path => '/vagrant/puppet/',	# puppet folder is put here...
		backup => false,		# don't use puppet to backup...
	}
}

As you can see, I include two classes. The first one installs and configures the puppetmaster, puppetdb, and so on. The second class runs an rsync from the vagrant deployed /vagrant/puppet/ directory to the proper directories inside of /etc/puppet/ and wherever else is appropriate. Each time I want to push new puppet code, I run vp puppet and then vp <host> of whichever host I want to test. You can even combine the two commands into a one-liner with && if you’d like.

The puppet-puppet module:

This is the hairy part. I’ve always had an issue with this module. I recently ripped out support for a lot of the old puppet 0.24 era features, and I’ve only since tested it on the recent 3.x series. A lot has changed from version to version, so it has been hard to follow this and keep it sane. There are serious improvements that could be made to the code. In fact, I wouldn’t recommend it unless you’re okay hacking on Puppet code:

https://github.com/purpleidea/puppet-puppet

Most importantly:

This was a long article! I could have split it up into multiple posts, gotten more internet traffic karma, and would have seemed like a much more prolific blogger as a result, but I figured you’d prefer it all in one big lot, and without any suspense. Prove me right by leaving me a tip, and giving me your feedback.

Happy hacking!

James

PS: You’ll want to be able to follow along with everything in this article if you want to use the upcoming Puppet-Gluster+Vagrant infrastructure that I’ll be releasing.

PPS: Heh heh heh…

PPPS: Get it? Vagrant -> Oscar the Grouch -> Muppets -> Puppet

 

Vagrant on Fedora with libvirt

Apparently lots of people are using Vagrant these days, so I figured I’d try it out. I wanted to get it working on Fedora, and without Virtualbox. This is an intro article on Vagrant, and what I’ve done. I did this on Fedora 19. Feel free to suggest improvements.

Intro:

Vagrant is a tool that easily provisions virtual machines, and then kicks off a configuration management deployment like Puppet. It’s often used for development. I’m planning on using it to test some Puppet-Gluster managed GlusterFS clusters.

Installation:

You should already have the base libvirt/QEMU packages already installed (if they’re not already present) and be comfortable with basic virtual machine concepts. If not, come back when you’re ready.

Fedora 20 was supposed to include Vagrant, but I don’t think this happened. In the meantime, I installed the latest x86_64 RPM from the Vagrant download page.

$ mkdir ~/vagrant
$ wget http://files.vagrantup.com/packages/a40522f5fabccb9ddabad03d836e120ff5d14093/vagrant_1.3.5_x86_64.rpm
$ sudo yum install vagrant_1.3.5_x86_64.rpm

EDIT: Please use version 1.3.5 only! The 1.4 series breaks compatibility with a lot of the necessary plugins. You might have success with different versions, but I have not tested them yet.

You’ll probably need some dependencies for the next few steps. Ensure they’re present:

$ sudo yum install libvirt-devel libxslt-devel libxml2-devel

The virsh and virt-manager tools are especially helpful additions. Install those too.

Boxes:

Vagrant has a concept of default “boxes”. These are pre-built images that you download, and use as base images for the virtual machines that you’ll be building. Unfortunately, they are hypervisor specific, and the most commonly available images have been built for Virtualbox. Yuck! To get around this limitation, there is an easy solution.

First we’ll need to install a special Vagrant plugin:

$ sudo yum install qemu-img # depends on this
$ vagrant plugin install vagrant-mutate

EDIT: Note that there is a bug on Fedora 20 that breaks mutate! Feel free to skip over the mutate steps below on Fedora, and use this image instead. You can install it with:

$ vagrant box add centos-6 https://download.gluster.org/pub/gluster/purpleidea/vagrant/centos-6.box --provider=libvirt

You’ll have to replace the precise32 name in the below Vagrantfile with centos-6.

END EDIT

Now download an incompatible box. We’ll use the well-known example:

$ vagrant box add precise32 http://files.vagrantup.com/precise32.box

Finally, convert the box so that it’s libvirt compatible:

$ vagrant mutate precise32 libvirt

This plugin can also convert to KVM friendly boxes.

You’ll need to make a working directory for Vagrant and initialize it:

$ mkdir test1
$ cd test1
$ vagrant init precise32

Hypervisor:

I initially tried getting this working with the vagrant-kvm plugin that Fedora 20 will eventually include, but I did not succeed. Instead, I used the vagrant-libvirt plugin:

$ vagrant plugin install vagrant-libvirt

EDIT: I forgot to mention that you’ll need to specify the --provider argument when running vagrant commands. I wrote about how to do this in my second article. You can use --provider=libvirt for each command or include the:

export VAGRANT_DEFAULT_PROVIDER=libvirt

line in your ~/.bashrc file.

END EDIT

I have found a number of issues with it, but I’ll show you which magic knobs I’ve used so that you can replicate my setup. Let me show you my Vagrantfile:

# -*- mode: ruby -*-
# vi: set ft=ruby :

VAGRANTFILE_API_VERSION = "2"

# NOTE: vagrant-libvirt needs to run in series (not in parallel) to avoid
# trying to create the network twice... eg: vagrant up --no-parallel
# alternatively, you can just create the vm's one at a time manually...

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|

	# Every Vagrant virtual environment requires a box to build from
	config.vm.box = "precise32"			# choose your own!

	# List each virtual machine
	config.vm.define :vm1 do |vm1|
		vm1.vm.network :private_network,
			:ip => "192.168.142.101",	# choose your own!
			:libvirt__network_name => "default"	# leave it
	end

	config.vm.define :vm2 do |vm2|
		vm2.vm.network :private_network,
			:ip => "192.168.142.102",	# choose your own!
			:libvirt__network_name => "default"	# leave it
	end

	# Provider-specific configuration
	config.vm.provider :libvirt do |libvirt|
		libvirt.driver = "qemu"
		# leave out host to connect directly with qemu:///system
		#libvirt.host = "localhost"
		libvirt.connect_via_ssh = false		# also needed
		libvirt.username = "root"
		libvirt.storage_pool_name = "default"
	end

	# Enable provisioning with Puppet. You might want to use the agent!
	config.vm.provision :puppet do |puppet|
		puppet.module_path = "modules"
		puppet.manifests_path = "manifests"
		puppet.manifest_file = "site.pp"
		# custom fact
		puppet.facter = {
			"vagrant" => "1",
		}
	end
end

A few caveats:

• The :libvirt__network_name => "default" needs to always be specified. If you don’t specify it, or if you specify a different name, you’ll get an error:

  Call to virDomainCreateWithFlags failed: Network not found: no network with matching name 'default'

• With this Vagrantfile, you’ll get an IP address from DHCP, and a static IP address from the :ip definition. If you attempt to disable DHCP with :libvirt__dhcp_enabled => false you’ll see errors:

  grep: /var/lib/libvirt/dnsmasq/*.leases: No such file or directory

  As a result, each machine will have two IP addresses.

• Running vagrant up caused some errors when more than one machine is defined. This was caused by duplicate attempts to create the same network. To work around this, you can either start each virtual machine manually, or use the –no-parallel option when the network is first created:

  $ vagrant up --no-parallel
  [...]
  <magic awesome happens here>

Commands:

The most common commands you’ll need are:

• vagrant init – initialize a directory
• vagrant up [machine] – start/build/deploy a machine
• vagrant ssh <machine> – connect to a machine
• vagrant halt [machine] – stop the machine
• vagrant destroy [machine] – remove/erase/purge the entire machine

I won’t go into further details here, because this information is well documented.

PolicyKit (polkit):

At this point you’re probably getting annoyed by having to repeatedly type your password to interact with your VM through libvirt. You’re probably seeing a dialog like this:

This should look familiar if you’ve used virt-manager before. When you open virt-manager, and it tries to connect to qemu:///system, PolicyKit does the right thing and ensures that you’re allowed to get access to the resource first! The annoying part is that you get repeatedly prompted when you’re using Vagrant, because it is constantly opening up and closing new connections. If you’re comfortable allowing this permanently, you can add a policy file:

[Allow james libvirt management permissions]
Identity=unix-user:james
Action=org.libvirt.unix.manage
ResultAny=yes
ResultInactive=yes
ResultActive=yes

Create this file (you’ll need root) as:

/etc/polkit-1/localauthority/50-local.d/vagrant.pkla

and then shouldn’t experience any more prompts when you try to manage libvirt! You’ll obviously want to replace the james string with whatever user account you’re using. For more information on the format of this file, and to learn other ways to do this read the pkla documentation.

If you want to avoid PolicyKit, you can connect to libvirtd over SSH, however I don’t have sshd running on my laptop, and I wanted to connect directly. The default vagrant-libvirt example demonstrates this method.

Puppet:

Provisioning machines without configuration management wouldn’t be very useful. Thankfully, Vagrant integrates nicely with Puppet. The documentation on this is fairly straightforward, so I won’t cover this part. I show a simple Puppet deployment in my Vagrantfile above, but a more complex setup involving puppet agent and puppetmasterd is possible too.

Conclusion:

Hopefully this makes it easier for you to hack in GNU/Linux land. I look forward to seeing this supported natively in Fedora, but until then, hopefully I’ve helped out with the heavy lifting.

Happy hacking!

James

Now syndicated on “Planet Fedora”

I’m now syndicated on the Fedora Project planet. If you haven’t read through my blog yet, let me introduce myself, I’m James, and I write The Technical Blog of James.

I’m a sysadmin, DevOps/Puppet hacker, I.T./network architect and physiologist. Hi! I run Fedora as my primary desktop, but I also use it for servers, particularly for development before future versions of RHEL and CentOS release.

I’m most well-known for Puppet-Gluster, but I’ve also written a decent Puppet-IPA (FreeIPA) module. I’m currently working on porting Puppet-Gluster to Fedora and looking forward to the upcoming release of Fedora 20.

Please feel free to comment or contact me and tell me which articles you like, and which you don’t. I’m on Twitter, and on IRC as purpleidea.

Happy hacking,

James