Wednesday, July 21, 2010

Bootstrapping EC2 instances with Chef

This is the third installment of my Chef post series (read the first and the second). This time I'll show how to use the Ubuntu EC2 instance bootstrap mechanism in conjunction with Chef and have the instance configure itself at launch time. I had a similar post last year, in which I was accomplishing a similar thing with puppet.

Why Chef this time, you ask? Although I am a Python guy, I prefer learning a smattering of Ruby rather than a proprietary DSL for configuration management. Also, when I upgraded my EC2 instances to the latest Ubuntu Lucid AMIs, puppet stopped working, so I was almost forced to look into Chef -- and I've liked what I've seen so far. I don't want to bad-mouth puppet though, I recommend you look into both if you need a good configuration management/deployment tool.

Here is a high-level view of the bootstrapping procedure I'm using:

1) You create Chef roles and tie them to cookbooks and recipes that you want executed on machines which will be associated with these roles.
2) You launch an EC2 Ubuntu AMI using any method you want (the EC2 Java-based command-line API, or scripts based on boto, etc.). The main thing here is that you pass a custom shell script to the instance via a user-data file.
3) When the EC2 instance boots up, it runs your custom user-data shell script. The script installs chef-client and its prerequisites, downloads the files necessary for running chef-client, runs chef-client once to register with the chef master and to run the recipes associated with its role, and finally runs chef-client in the background so that it wakes up and executed every N minutes.

Here are the 3 steps in more detail.

1) Create Chef roles, cookbooks and recipes

I already described how to do this in my previous post.

For the purposes of this example, let's assume we have a role called 'base' associated with a cookbook called 'base' and another role called 'myapp' associated with a cookbook called 'myapp'.

The 'base' cookbook contains recipes that can do things like installing packages that are required across all your applications, creating users and groups that you need across all server types, etc.

The 'myapp' cookbook contains recipes that can do things specific to one of your particular applications -- in my case, things like installing and configuring tornado/nginx/haproxy.

As a quick example, here's how to add a user and a group both called "myoctopus". This can be part of the default recipe in the cookbook 'base' (in the file cookbooks/base/recipes/default.rb).

The home directory is /home/myoctopus, and we make sure that directory exists and is owned by the user and group myoctopus.

group "myoctopus" do
action :create
end

user "myoctopus" do
gid "myoctopus"
home "/home/myoctopus"
shell "/bin/bash"
end

%w{/home/myoctopus}.each do |dir|
directory dir do
owner "myoctopus"
group "myoctopus"
mode "0755"
action :create
not_if "test -d #{dir}"
end
end


The role 'base' looks something like this, in a file called roles/base.rb:

name "base"
description "Base role (installs common packages)"
run_list("recipe[base]")


The role 'myapp' looks something like this, in a file called roles/myapp.rb:


name "myapp"
description "Installs required packages and applications for an app server"
run_list "recipe[memcached]", "recipe[myapp::tornado]"


Note that the role myapp specifies 2 recipes to be run: one is the default recipe of the 'memcached' cookbook (which is part of the Opscode cookbooks), and one is a reciped called tornado which is part of the myapp cookbook (the file for that recipe is cookbooks/myapp/recipes/tornado.rb). Basically, to denote a recipe, you either specify its cookbook (if the recipe is the default recipe of that cookbook), or you specify cookbook::recipe_name (if the recipe is non-default).

So far, we haven't associated any clients with these roles. We're going to do that on the client EC2 instance. This way the Chef server doesn't have to do any configuration operations during the bootstrap of the EC2 instance.

2) Launching an Ubuntu EC2 AMI with custom user-data

I wrote a Python wrapper around the EC2 command-line API tools. To launch an EC2 instance, I use the ec2-run-instances command-line tool. My Python script also takes a command line option called chef_role, which specifies the Chef role I want to associate with the instance I am launching. The main ingredient in the launching of the instance is the user-data file (passed to ec2-run-instances via the -f flag).

I use this template for the user-data file. My Python wrapper replaces HOSTNAME with an actual host name that I pass via a cmdline option. The Python wrapper also replaces CHEF_ROLE with the value of the chef_role cmdline option (which defaults to 'base').

The shell script which makes up the user-data file does the following:

a) Overwrites /etc/hosts with a version that has hardcoded values for chef.mycloud and mysite.com. The chef.mycloud.com box is where I run Chef server, and mysite.com is a machine serving as a download repository for utility scripts.

b) Downloads Eric Hammond's runurl script, which it uses to run other utility scripts.

c) Executes via runurl the script mysite.com/customize/hostname and passes it the real hostname of the machine being launched. The hostname script simply sets the hostname on the machine:

#!/bin/bash
hostname $1
echo $1 > /etc/hostname


d) Executes via runurl the script mysite.com/customize/hosts and passes it 2 arguments: add and self. Here's the hosts script:

#!/bin/bash
if [[ "$1" == "add" ]]; then
IPADDR=`ifconfig | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1}'`
HOSTNAME=`hostname`
sed -i "s/127.0.0.1 localhost.localdomain localhost/127.0.0.1 localhost.localdomain localhost\n$IPADDR $HOSTNAME.mycloud.com $HOSTNAME\n/g" /etc/hosts
fi

What this does is it adds the internal IP of the machine being launched to /etc/hosts and associates it with both the FQDN and the short hostname. The FQDN bit is important for chef configuration purposes. It needs to come before the short form in /etc/hosts. I could have obviously also used DNS, but at bootstrap time I prefer to deal with hardcoded host names for now.

Update 07/22/10

Patrick Lightbody sent me a note saying that it's easier to get the local IP address of the machine by using one of the handy EC2 internal HTTP queries.

If you run "curl -s http://169.254.169.254/latest/meta-data" on any EC2 instance, you'll see a list of variables that you can inspect that way. For the local IP, I modified my script above to use:

IPADDR=`curl -s http://169.254.169.254/latest/meta-data/local-ipv4`

e) Finally, and most importantly for this discussion, executes via runurl the script mysite.com/install/chef-client and passes it the actual value of the cmdline argument chef_role. The chef-client script does the heavy lifting in terms of installing and configuring chef-client on the instance being launched. As such, I will describe it in the next step.

3) Installing and configuring chef-client on the newly launched instance

Here is the chef-client script I'm using. The comments are fairly self-explanatory. Because I am passing CHEF_ROLE as its first argument, the script knows which role to associate with the client. It does it by downloading the appropriate chef.${CHEF_ROLE}.json. To follow the example, I have 2 files corresponding to the 2 roles I created on the Chef server.

Here is chef.base.json:

{
"bootstrap": {
"chef": {
"url_type": "http",
"init_style": "init",
"path": "/srv/chef",
"serve_path": "/srv/chef",
"server_fqdn": "chef.mycloud.com"
}
},
"run_list": [ "role[base]" ]
}

The only difference in chef.myapp.json is the run_list, which in this case contains both roles (base and myapp):

{
"bootstrap": {
"chef": {
"url_type": "http",
"init_style": "init",
"path": "/srv/chef",
"serve_path": "/srv/chef",
"server_fqdn": "chef.mycloud.com"
}
},
"run_list": [ "role[base]", "role[myapp]" ]
}

The chef-client script also downloads the client.rb file which contains information about the Chef server:



log_level :info
log_location STDOUT
ssl_verify_mode :verify_none
chef_server_url "http://chef.mycloud.com:4000"

validation_client_name "chef-validator"
validation_key "/etc/chef/validation.pem"
client_key "/etc/chef/client.pem"

file_cache_path "/srv/chef/cache"
pid_file "/var/run/chef/chef-client.pid"

Mixlib::Log::Formatter.show_time = false

Note that the client knows the IP address of chef.mycloud.com because we hardcoded it in /etc/hosts.

The chef-client script also downloads validation.pem, which is an RSA key file used by the Chef server to validate the client upon the initial connection from the client.

The last file downloaded is the init script for launching chef-client automatically upon reboots. I took the liberty of butchering this sample init script and I made it much simpler (see the gist here but beware that it contains paths specific to my environment).

At this point, the client is ready to run this chef-client command which will contact the Chef server (via client.rb), validate itself (via validation.pem), download the recipes associated with the roles specified in chef.json, and run these recipes:

chef-client -j /etc/chef/chef.json -L /var/log/chef.log -l debug

I run the command in debug mode and I specify a log file location (the default output is stdout) so I can tell what's going on if something goes wrong.

That's about it. At this point, the newly launched instance is busy configuring itself via the Chef recipes. Time to sit back and enjoy your automated bootstrap process!

The last lines in chef-client remove the validation.pem file, which is only needed during the client registration, and run chef-client again, this time in the background, via the init script. The process running in the background looks something like this in my case:
/usr/bin/ruby1.8 /usr/bin/chef-client -L /var/log/chef.log -d -j /etc/chef/chef.json -c /etc/chef/client.rb -i 600 -s 30

The -i 600 option means chef-client will contact the Chef server every 600 seconds (plus a random interval given by -s 30) and it will inquire about additions or modifications to the roles it belongs to. If there are new recipes associated with any of the roles, the client will download and run them.

If you want to associate the client to new roles, you can just edit the local file /etc/chef/chef.json and add the new roles to the run_list.

Thursday, July 15, 2010

Tracking and visualizing mail logs with MongoDB and gviz_api

To me, nothing beats a nice dashboard for keeping track of how your infrastructure and your application are doing. At Evite, sending mail is a core part of our business. One thing we need to ensure is that our mail servers are busily humming away, sending mail out to our users. To this end, I built a quick outgoing email tracking tool using MongoDB and pymongo, and I also put together a dashboard visualization of that data using the Google Visualization API via the gviz_api Python module.

Tracking outgoing email from the mail logs with pymongo

Mail logs are sent to a centralized syslog. I have a simple Python script that tails the common mail log file every 5 minutes, counts the lines that conform to a specific regular expression (looking for a specific msgid pattern), then inserts that count into a MongoDB database. Here's the snippet of code that does that:

import datetime
from pymongo import Connection

conn = Connection(host="myhost.example.com")
db = conn.logs
maillogs = db.mail
d = {}
now = datetime.now()
d['insert_time'] = now
d['msg_count'] = msg_count
maillogs.save(d)

I use the pymongo module to open a connection to the host running the mongod daemon, then I declare a database called logs and a collection called maillogs within that database. Note that both the database and the collection are created on the fly in case they don't exist.

I then instantiate a Python dictionary with two keys, insert_time and msg_count. Finally, I use the save method on the maillogs collection to insert the dictionary into the MongoDB logs database. Can't get any easier than this.

Visualizing the outgoing email count with graph_viz

I have another simple Python script which queries the MongoDB logs database for all documents that have been inserted in the last hour. Here's how I do it:


MINUTES_AGO=60
conn = Connection()
db = conn.logs
maillogs = db.mail
now = datetime.datetime.now()
minutes_ago = now + datetime.timedelta(minutes=-MINUTES_AGO)
rows = maillogs.find({'insert_time': {"$gte": minutes_ago}})

As an aside, when querying MongoDB databases that contain documents with timestamp fields, the datetime module will become your intimate friend.

Just remember that you need to pass datetime objects when you put together a pymongo query. In the case above, I use the now() method to get the current timestamp, then I use timedelta with minutes=-60 to get the datetime object corresponding to 'now minus 1 hour'.

The gviz_api module has decent documentation, but it still took me a while to figure out how to use it properly (thanks to my colleague Dan Mesh for being the trailblazer and providing me with some good examples).

I want to graph the timestamps and message counts from the last hour. Using the pymongo query above, I get the documents inserted in MongoDB during the last hour. From that set, I need to generate the data that I am going to pass to gviz_api:


chart_data = []
for row in rows:
insert_time = row['insert_time']
insert_time = insert_time.strftime(%H:%M')
msg_count = int(row['msg_count'])
chart_data.append([insert_time, msg_count])

jschart("Outgoing_mail", chart_data)


In my case, chart_data is a list of lists, each list containing a timestamp and a message count.

I pass the chart_data list to the jschart function, which does the Google Visualization magic:

def jschart(name, chart_data):
description = [
("time", "string"),
("msg_count", "number", "Message count"),
]

data = []
for insert_time, msg_count in chart_data:
data.append((insert_time, msg_count))

# Loading it into gviz_api.DataTable
data_table = gviz_api.DataTable(description)
data_table.LoadData(data)

# Creating a JSON string
json = data_table.ToJSon()

name = "OUTGOING_MAIL"
html = TEMPL % {"title" : name, "json" : json}
open("charts/%s.html" % name, "w").write(html)

The important parts in this function are the description and the data variables. According to the docs, they both need to be of the same type, either dictionary or list. In my case, they're both lists. The description denotes the schema for the data I want to chart. I declare two variables I want to chart, insert_time of type string, and msg_count of type number. For msg_count, I also specify a user-friendly label called 'Message count', which will be displayed in the chart legend.

After constructing the data list based on chart_data, I declare a gviz_api DataTable, I load the data into it, I call the ToJSon method on it to get a JSON string, and finally I fill in a template string, passing it a title for the chart and the JSON data.

The template string is an HTML + Javascript snippet that actually talks to the Google Visualization backend and tells it to create an Area Chart. Click on this gist to view it.

That's it. I run the gviz_api script every 5 minutes via crontab and I generate an HTML file that serves as my dashboard.

I can easily also write a Nagios plugin based on the pymongo query, which would alert me for example if the number of outgoing email messages is too low or too high. It's very easy to write a Nagios plugin by just having a script that exits with 0 for success, 1 for warnings and 2 for critical errors. Here's a quick example, where wlimit is the warning threshold and climit is the critical threshold:


def check_maillogs(wlimit, climit):
# MongoDB
conn = Connection()
db = conn.logs
maillogs = db.mail
now = datetime.datetime.now()
minutes_ago = now + datetime.timedelta(minutes=-MINUTES_AGO)
count = maillogs.find({'insert_time': {"$gte": minutes_ago}}).count()
rc = 0
if count > wlimit:
rc = 1
if count > climit:
rc = 2
print "%d messages sent in the last %d minutes" % (count, MINUTES_AGO)
return rc


Update #1
See Mike Dirolf's comment on how to properly insert and query timestamp-related fields. Basically, use datetime.datetime.utcnow() instead of now() everywhere, and convert to local time zone when displaying.

Update #2
Due to popular demand, here's a screenshot of the chart I generate. Note that the small number of messages is a very, very small percentage of our outgoing mail traffic. I chose to chart it because it's related to some new functionality, and I want to see if we're getting too few or too many messages in that area of the application.

Friday, July 09, 2010

Working with Chef cookbooks and roles

Welcome to the second installment of my Chef saga (you can read the first one here). This time I will walk you through creating your own cookbook, modifying an existing cookbook, creating a role and adding a client machine to that role. As usual, I got much help from the good people on the #chef IRC channel, especially the omnipresent @kallistec. All these tasks are also documented in one form or another on the Chef wiki, but I found it hard to put them all together, hence this blog post.

Downloading the Opscode Chef cookbooks

Step 0 for this task is to actually clone the Opscode repository. I created a directory called /srv/chef/repos on my Chef server box and ran this command inside it:

# git clone git://github.com/opscode/chef-repo.git

This will create /srv/chef/repos/chef-repo with a bunch of sub-directories, one of them being cookbooks.
I deleted the cookbooks directory and cloned the Opscode cookbooks in its place:

# cd /srv/chef/repos/chef-repo
# git clone git://github.com/opscode/cookbooks



Uploading the cookbooks to the Chef server

Just downloading the cookbooks somewhere on the file system is not enough. The Chef server needs to be made aware of their existence. You do that with the following knife command (which I ran on the Chef server box):

# knife cookbook upload -a -o /srv/chef/repos/chef-repo/cookbooks

BTW, if you specified a non-default configuration file location for knife when you configured it (I specified /etc/chef/knife.rb for example) then you need to make a symlink from that file to ~/.chef/knife.rb, otherwise knife will complain about not finding a config file. At least it complained to me in its strange Swedish accent.

To go back to the knife command above: it says to upload all (-a) cookbooks it finds under the directory specified with -o.

Modifying an existing cookbook

If you look closely under the Opscode cookbooks, there's one called python. A cookbook contains one or more recipes, which reside under COOKBOOK_NAME/recipes. Most cookbooks have only one recipe which is a file called default.rb. In the case of the python cookbook, this recipe ensures that certain python packages such as python-dev, python-imaging, etc. get installed on the node running Chef client. To add more packages, simply edit default.rb (there's a certain weirdness in modifying a Ruby file to make a node install more Python packages....) and add your packages of choice.

Again, modifying a cookbook recipe on the file system is not enough; you need to let the Chef server know about the modification, and you do it by uploading the modified cookbook to the Chef server via knife:

# knife cookbook upload python -o /srv/chef/repos/chef-repo/cookbooks

Note the modified version of the 'knife cookbook upload' command. In this case, we don't specify '-a' for all cookbooks, but instead we specify a cookbook name (python). However, the directory remains the same. Do not make the mistake of specifying /srv/chef/repos/chef-repo/cookbooks/python as the target of your -o parameter, because it will not work. Trust me, I tried it until I was enlightened by @kallistec on the #chef IRC channel.

Creating your own cookbook

It's time to bite the bullet and create your own cookbook. Chef makes it easy to create all the files needed inside a cookbook. Run this command when in the top-level chef repository directory (/srv/chef/repos/chef-repo in my case):

# rake new_cookbook COOKBOOK=octopus

(like many other people, I felt the urge to cook Paul the Octopus when he accurately predicted Germany's loss to Spain)

This will create a directory cscp neo-app01:/opt/evite/etc/ad_urls.json .
alled octopus under chef-repo/cookbooks and it will populate it with many other directories and files. At a minimum, you need to modify only octopus/recipes/default.rb. Let's assume you want to install some packages. You can take some inspiration from other recipes (build-essential for example), but it boils down to something like this:

include_recipe "build-essential"
include_recipe "ntp"
include_recipe "python"
include_recipe "screen"
include_recipe "git"

%w{chkconfig libssl-dev syslog-ng munin-node}.each do |pkg|
  package pkg do
    action :install
  end
end

Note that I'm also including other recipes in my default.rb file. They will be executed on the Chef client node, BUT they also need to be specified in the metadata file cookbooks/octopus/metadata.rb as dependencies, so that the Chef client node knows that it needs to download them before running them. Trust me on this one, I speak again from bitter experience. This is how my metadata.rb file looks like:

maintainer        "My Organization"
maintainer_email  "admin@example.com"
license           "Apache 2.0"
description       "Installs required packages for My Organization applications"
version           "0.1"
recipe            "octopus", "Installs required packages for My Organization applications"
depends           "build-essential"
depends           "ntp"
depends           "python"
depends           "screen"
depends           "git"

%w{ fedora redhat centos ubuntu debian }.each do |os|
  supports os
end

Now it's time to upload our brand new cookbook to the Chef server. As before, we'll use the knife utility:

# knife cookbook upload octopus -o /srv/chef/repos/chef-repo/cookbooks

If you have any syntax errors in the recipe file or the metadata file, knife will let you know about them. To verify that the cookbook was uploaded successfully to the server, run this command, which should list your cookbook along the others that you uploaded previously:

# knife cookbook list

Creating a role and associating a chef client machine with it

Chef supports the notion of roles, which is very important for automated configuration management because you can assign a client node to one or more roles (such as 'web' or 'db' for example) and have it execute recipes associated with those roles.

To add a role, simply create a file under chef-repo/roles. I called mine base.rb, with the contents:

name "base"
description "Base role (installs common packages)"
run_list("recipe[octopus]")

It's pretty self-explanatory. Clients associated with the 'base' role will run the 'octopus' recipe.

As with cookbooks, we need to upload the newly created role to the Chef server. The following knife command will do it (assuming you're in the chef-repo directory):

# knife role from file roles/base.rb

To verify that the role has been uploaded, you can run:

# knife role show base

and it should show a JSON output similar to:

{
    "name": "base",
    "default_attributes": {
    },
    "json_class": "Chef::Role",
    "run_list": [
      "recipe[octopus]"
    ],
    "description": "Base role (installs common packages)",
    "chef_type": "role",
    "override_attributes": {
    }
}

Now it's time to associate a Chef client with the new role. You can see which clients are already registered with your Chef server by running:

# knife client list

Now pick a client and see which roles it is associated with:

# knife node show client01.example.com -r
{
  "run_list": [
  ]
}

The run_list is empty for this client. Let's associate it with the role we created, called 'base':

# knife node run_list add client01.example.com "role[base]"

You should now see the 'base' role in the run_list:


# knife node show client01.example.com -r
{
  "run_list": [
    "role[base]"
  ]
}

The next time client01.example.com will run chef-client, it will figure out it is part of the 'base' role, and it will follow the role' run_list by downloading and running the 'octopus' recipe from the Chef server.

In the next installment, I will talk about how to automatically bootstrap a Chef client in an EC2 environment. The goal there is to launch a new EC2 instance, have it install Chef client, have it assign a role to itself, then have it talk to the Chef server, download and run the recipes associated with the role.

Tuesday, July 06, 2010

Chef installation and minimal configuration

I started to play with Chef the other day. The instructions on the wiki are a bit confusing, but help on twitter (thanks @jtimberman) and on the #chef IRC channel (thanks @kallistec) has been great. I am at the very minimal stage of having a chef client talking to a chef server. I hasten to write down what I've done so far, both for my own sake and for others who might want to do the same. My OS is Ubuntu 10.04 32-bit on both machines.

First of all: as the chef wiki says, make sure you have FQDNs correctly set up on both client and server, and that they can ping each other at a minimum using the FQDN. I added the FQDN to the local IP address line in /etc/hosts, so that 'hostname -f' returned the FQDN correctly. In what follows, my Chef server machine is called chef.example.com and my Chef client machine is called client.example.com.

Installing the Chef server


Here I went the Ruby Gems route, because the very latest Chef (0.9.4) had not been captured in the Ubuntu packages yet when I tried to install it.

a) install pre-requisites

# apt-get install ruby ruby1.8-dev libopenssl-ruby1.8 rdoc ri irb build-essential wget ssl-cert

b) install Ruby Gems

# wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
# tar xvfz rubygems-1.3.7.tgz
# cd rubygems-1.3.7
# ruby setup.rb
# ln -sfv /usr/bin/gem1.8 /usr/bin/gem

c) install the Chef gem

# gem install chef

d) install the Chef server by bootstrapping with the chef-solo utility

d1) create /etc/chef/solo.rb with contents:


file_cache_path "/tmp/chef-solo"
cookbook_path "/tmp/chef-solo/cookbooks"
recipe_url "http://s3.amazonaws.com/chef-solo/bootstrap-latest.tar.gz"

d2) create /etc/chef/chef.json with contents:

{
"bootstrap": {
"chef": {
"url_type": "http",
"init_style": "runit",
"path": "/srv/chef",
"serve_path": "/srv/chef",
"server_fqdn": "chef.example.com",
"webui_enabled": true
}
},
"run_list": [ "recipe[bootstrap::server]" ]
}

d3) run chef-solo to bootstrap the Chef server install:

# chef-solo -c /etc/chef/solo.rb -j /etc/chef/chef.json

e) create an initial admin client with the Knife utility, to interact with the API

#knife configure -i
Where should I put the config file? [~/.chef/knife.rb]
Please enter the chef server URL: [http://localhost:4000] http://chef.example.com
Please enter a clientname for the new client: [root]
Please enter the existing admin clientname: [chef-webui]
Please enter the location of the existing admin client's private key: [/etc/chef/webui.pem]
Please enter the validation clientname: [chef-validator]
Please enter the location of the validation key: [/etc/chef/validation.pem]
Please enter the path to a chef repository (or leave blank):

f) create an intial Chef repository

I created a directory called /srv/chef/repos , cd-ed to it and ran this command:

# git clone git://github.com/opscode/chef-repo.git

At this point, you should have a functional Chef server, although it won't help you much unless you configure some clients.

Installing a Chef client

Here's the bare minimum I did to get a Chef client to just talk to the Chef server configured above, without actually performing any cookbook recipe yet (I leave that for another post).

The first steps are very similar to the ones I followed when I installed the Chef server.


a) install pre-requisites

# apt-get install ruby ruby1.8-dev libopenssl-ruby1.8 rdoc ri irb build-essential wget ssl-cert

b) install Ruby Gems

# wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
# tar xvfz rubygems-1.3.7.tgz
# cd rubygems-1.3.7
# ruby setup.rb
# ln -sfv /usr/bin/gem1.8 /usr/bin/gem

c) install the Chef gem

# gem install chef

d) install the Chef client by bootstrapping with the chef-solo utility

d1) create /etc/chef/solo.rb with contents:

file_cache_path "/tmp/chef-solo"
cookbook_path "/tmp/chef-solo/cookbooks"
recipe_url "http://s3.amazonaws.com/chef-solo/bootstrap-latest.tar.gz"
Caveat for this stepCaveat for this step
d2) create /etc/chef/chef.json with contents:

{
"bootstrap": {
"chef": {
"url_type": "http",
"init_style": "runit",
"path": "/srv/chef",
"serve_path": "/srv/chef",
"server_fqdn": "chef.example.com",
"webui_enabled": true
}
},
"run_list": [ "recipe[bootstrap::client]" ]
}

Note that the only difference so far between the Chef server and the Chef client bootstrap files is the one directive at the end of chef.json, which is bootstrap::server for the server and bootstrap::client for the client.

Caveat for this step: if you mess up and bootstrap the client using the wrong chef.json file containing the bootstrap::server directive, you will end up with a server and not a client. I speak from experience -- I did exactly this, then when I tried to run chef-client on this box, I got:

WARN: HTTP Request Returned 401 Unauthorized: Failed to authenticate!

/usr/lib/ruby/1.8/net/http.rb:2097:in `error!': 401 "Unauthorized" (Net::HTTPServerException)

d3) run chef-solo to bootstrap the Chef client install:

# chef-solo -c /etc/chef/solo.rb -j /etc/chef/chef.json

At this point, you should have a file called client.rb in /etc/chef on your client machine, with contents similar to:

#
# Chef Client Config File
#
# Dynamically generated by Chef - local modifications will be replaced
#

log_level :info
log_location STDOUT
ssl_verify_mode :verify_none
chef_server_url "http://chef.example.com:4000"

validation_client_name "chef-validator"
validation_key "/etc/chef/validation.pem"
client_key "/etc/chef/client.pem"

file_cache_path "/srv/chef/cache"
pid_file "/var/run/chef/chef-client.pid"

Mixlib::Log::Formatter.show_time = false
Caveat for this stepCaveat for this stepCaveat for this step
e) validate the client against the server

e1) copy /etc/chef/validation.pem from the server to /etc/chef on the client
e2) run chef-client on the client; for debug purposes you can use:

# chef-client -l debug

If everything goes well, you should see a message of the type:

# chef-client
INFO: Starting Chef Run
INFO: Client key /etc/chef/client.pem is not present - registering
WARN: Node client.example.com has an empty run list.
INFO: Chef Run complete in 1.209376 sec WARN: HTTP Request Returned 401 Unauthorized: Failed to authenticate!
31 < ggheo > 30 /usr/lib/ruby/1.8/nCaveat for this stepet/http.rb:2097:in `error!': 401 "Unauthorized" (Net::HTTPServerException)onds
INFO: Running report handlers
INFO: Report handlers complete

You should also have a file called client.pem containing a private key that the client will be using when talking to the server. At this point, you should remove validation.pem from /etc/chef on the client, as it is not needed any more.

You can also run this command on the server to see if the client got registered with it:

# knife client list -c /etc/chef/knife.rb

The output should be something like:

[
"chef-validator",
"chef-webui",
"chef.example.com",
"root",
"client.example.com"
]

That's it for now. As I warned you, nothing exciting happened here except for having a Chef client that talks to a server but doesn't actually DO anything. Stay tuned for more installments in my continuing chef saga though...