I need to do a two step installation of a CentOS6 host with puppet (currently using puppet apply) and got stuck. Not even sure it's currently possible today.
Step 1, setup of base system e.g. setup hosts, ntp, mail and some driver stuff.
reboot required
Step 2, setup of a custom service.
Can this bee done a smooth way? I'm not very familiar with the puppet environment yet.
First off, I very much doubt that any setup steps on a CentOS machine strictly require a reboot. It is usually sufficient to restart the right set of services to make all settings take effect.
Anyway, basic approach to this type of problem could be to
Define a custom fact that determines whether a machine is ready to receive the final configuration steps (Step 2 in your question)
Protect the pertinent parts of your manifest with an if condition that uses that fact value.
You may want to create a file first, then delete it when you are done installing the base system (ntp in the below example)
for example
exec { '/tmp/reboot':
path => "/usr/bin:/bin:/sbin",
command => 'touch /tmp/reboot',
onlyif => 'test ! -f /tmp/rebooted',
}
service { 'ntp':
require => Exec['/tmp/reboot'],
...
}
exec { 'reboot':
command => "mv /tmp/reboot /tmp/rebooted; reboot",
path => "/usr/bin:/bin:/sbin",
onlyif => "test -f /tmp/reboot",
require => Service['ntp'],
creates => '/tmp/rebooted',
}
Related
We have RedHat 7.2 Linux OS and use puppet to perform our tasks. I am using puppet to install some software, which has worked fine and now the final step is to create an OS level service. In earlier versions of RHEL, we used chkconfig but that has been replaced with systemctl. Of course, the recommended way of performing this task is using a service. Since this is a custom software, I have my own startup script that I usually copy over to /etc/init.d, run chkconfig and then startup the service. How do I perform these tasks via Puppet for RedHat 7.2 OS ? I only want to create the service (not start it up or anything). This way, when the server reboots, the service will startup the app.
EDIT :
#redstonemercury for RHEL 7 I would think the following would be required. But your suggestion definitely helps as I was thinking along the same lines.
https://serverfault.com/questions/814611/puppet-generated-systemd-unit-files
file { '/lib/systemd/system/myservice.service':
mode => '0644',
owner => 'root',
group => 'root',
content => template('modulename/myservice.systemd.erb'),
}~>
exec { 'myservice-systemd-reload':
command => 'systemctl daemon-reload',
path => [ '/usr/bin', '/bin', '/usr/sbin' ],
refreshonly => true,
}
In puppet, use a package resource to install the package (assuming it's in repos that you're declaring already), then use a file resource to declare the /etc/init.d file, and put require => Package[<package_resource_name>] as a parameter in the file declaration to ensure the custom file gets created after the package has installed (so doesn't potentially get overwritten by the package's /etc/init.d file). E.g.:
package { 'mypackage':
ensure => present,
}
file { '/etc/init.d/mypackage':
ensure => present,
content => template('mypackage/myinitd'),
require => Package['mypackage'],
}
This is if you want to use a template. For a file, instead of content use source: source => puppet://modules/mypackage/myinitd
I'm a puppet beginner - so bear with me :)
I'm trying to write a module that does the following :
Check if a package is installed with the latest version in the repos
If the package needs to be installed, then config files will be copied from puppet source location, to client. Then the package will be installed
Once files are copied and package installed, run the script that will use the config files on the client to apply the necessary settings.
Once all of this are done, remove the copied files on client
I've come up with the following :
class somepackage(
$package_files_base = "/var/tmp",
$package_setup = "/var/tmp/package-setup.sh",
$ndc_file = "/var/tmp/somefile.ndc",
$osd_file = "/var/tmp/somefile.osd",
$nds_file = "/var/tmp/somefile.nds",
$configini_file = "/var/tmp/somefile.ini",
$required_files = ["$package_setup", "$ndc_file", "$osd_file", $nds_file", "$configini_file"])
{
package { 'some package':
ensure => 'latest',
notify => Exec['Package Setup'],
}
file { 'Package Setup Files':
path => $package_files_base,
ensure => directory,
replace => false,
recurse => true,
source => "puppet:///modules/somepackage/${::domain}",
mode => '0755',
}
exec { 'Package Setup':
command => "$package_setup",
logoutput => true,
timeout => 1800,
require => [ File['Package Setup Files']],
refreshonly => true,
notify => Exec['Remove config files'],
}
exec { 'Remove config files':
path => ['/usr/bin','/usr/sbin','/bin','/sbin'],
command => "rm \"${package_setup}\" \"${ndc_file}\" \"${osd_file}\" \"${nds_file}\" \"${configini_file}\"",
refreshonly => true,
}
}
While this achieves most of what I want to do, I notice that upon rerunning puppet apply the files, although they were being removed, were being recopied.
I can understand why this happens, but I don't know how to code it so that the files get copied ONLY if the package gets updated/installed (e.g. package wasn't installed or old). Otherwise the files will get copied over and over again every time puppet runs every 30 min (default setup) on the client I assume... I tried using the replace => false to prevent this but that just means the files wont ever get removed from /var/tmp after the first run of the class, because it only prevents subsequent runs of the class to re-copy the files (from my testing). This does prevent the redundant, repetitive copying - however I just want the files to be gone the first time!
Is this possible? Head hurts :(
Thanks in advance! We're running Puppet version 3.8.6 on EL7.3.
EDIT: To be clear, this is the bit that I'm struggling with: the resource file { 'Package Setup Files':. This keeps getting files copied even though the package isn't updated/installed. How do I prevent this from happening?
Here are some suggestions.
1) Recommendation for a short term solution
Stop trying to clean up those files if you do not need to. Put them in /opt and forget about them. Better still, have Puppet place a README file in there with them that will explain to your future self and to your fellow admins what they are and why they are there.
While I completely understand the desire to clean up, you need to weigh the cost of having a few old files in a directory somewhere against the cost of having complicated logic in the Puppet code that will not make any sense to anyone in a few months.
This is what I would do and in my experience it is also what most Puppet module authors do with these sorts of set up files.
2) Consider an orchestration framework
That said, it appears to me that you are trying to use Puppet to do operational tasks, and while it can kind of do operational tasks (via features like ensure => latest etc) it is really intended to be a configuration management tool.
I recommend people use Puppet to ensure => installed for packages (make sure Puppet can install the app properly if you need to fully rebuild the node); then delegate the problem of applying version upgrades and hotfixes etc outside of Puppet.
There are a few reasons for this.
Puppet is a declarative configuration management system; your Puppet code should define an end-state. Puppet is not like a shell script, where instead of an end-state, you define steps that change the state of a server imperatively, "one step at a time".
The first problem with ensure => latest is philosophical.
latest does not define a single end-state. The behaviour of your code at time X is different from the behaviour at time Y. So your code is not idempotent.
The second problem is practical. You can never solve the problem of RPM updates in a general way using Puppet, because Puppet can never know about all of the RPMs and their dependencies in your system. So, one way or another, you still need a specialised tool for managing the version updates.
So, since you will need a specialised tool for managing the version updates anyway, it is cleaner to draw a clear boundary between the two tools' roles: always use Puppet to manage the configuration and the initial installation; and then always use the other tool to manage the updates.
Ok, great. I see in your comments that you already have a Red Hat Satellite server, and you have written:
...some hosts within the Satellite have got an older version of the
software within yum. But we don't update this software very
often.....maybe once every year.
So, it sounds like you are using Puppet here to work around a problem in the way you are using Satellite. Is it possible to address this by fixing the way you use Satellite? If so, I think that will be cleaner.
Of course, sometimes the right thing to do is use a work-around, and that's why I provided some other options.
3) If you really really want Puppet to clean up those files
Perhaps move the logic inside a shell script. Something like:
class somepackage {
$shell =
'#!/bin/bash
# maybe use wget instead of puppet to get the files
wget http://a.b/c.tgz
tar zxf c.tgz
# install stuff
# clean up stuff
'
file { '/usr/local/bin/installer.sh':
ensure => file,
mode => '0755',
content => $shell,
}
package { 'some package':
ensure => latest,
notify => Exec['installer'],
}
exec { 'installer':
command => '/usr/local/bin/installer.sh',
refreshonly => true,
require => File['/usr/local/bin/installer.sh'],
}
}
The following is a simplified manifest I am running:
package {'ruby2.4':
ensure => installed
}
exec { "gem2.4_install_bundler":
command => "/usr/bin/gem2.4 install bundler",
require => Package['ruby2.4']
}
Puppet apply runs this manifest correctly i.e
installs ruby2.4 package (which includes gem2.4)
Installs bundler using gem2.4
However, puppet apply --noop FAILS because puppet cannot find the executable '/usr/bin/gem2.4' because ruby2.4 is not installed with --noop.
My question is if there is a standard way to test a scenario like this with puppet apply --noop? To validate that my puppet manifest is executing correctly?
It occurs to me that I may have to parse the output and validate the order of the executions. If this is the case, is there a standard way/tool for this?
A last resort is a very basic check that the puppet at least runs, which can be determined with the --detailed-exitcodes option. (a code different to 1).
Thank you in advance
rspec-puppet is the standard tool for that level of verification. It can build a catalog from the manifest (e.g. for a class, defined type, or host) and then you can write tests to verify the contents.
In your case you could verify that the package resource exists, that the exec resource exists, and verify the ordering between them. This would be just as effective as running the agent with --noop mode and parsing the output - but easier and cheaper to run.
rspec-puppet works best with modules, so assuming you follow the setup for your module from the website (adding rspec-puppet to your Gemfile, running rspec-puppet-init), and let's say this is in a class called ruby24, a simple spec in spec/classes/ruby24_spec.rb would be:
require 'spec_helper'
describe 'ruby24' do
it { is_expected.to compile.with_all_deps }
it { is_expected.to contain_package('ruby2.4').with_ensure('installed') }
it { is_expected.to contain_exec('gem2.4_install_bundler').with_command('/usr/bin/gem2.4 install bundler') }
it { is_expected.to contain_exec('gem2.4_install_bundler').that_requires('Package[ruby2.4]') }
end
I wrote a simple module to install a package (BioPerl) on a Ubuntu VM. The whole init.pp file is here:
https://gist.github.com/anonymous/17b4c31bf7309aff14dfdcd378e44f40
The problem is it doesn't work, and it gives me no feedback to let me know why it doesn't work. There are 3 simple steps in the module. I checked and it didn't do any of them. Heres the first 2:
Step 1: Download an archive and save it to /usr/local/lib
exec { 'bioperl-download':
command => "sudo /usr/bin/wget --no-check-certificate -O ${archive_path} ${package_uri}",
require => Package['wget']
}
Step 2: Extract the archive
exec { 'bioperl-extract':
command => "sudo /usr/bin/tar zxvf ${archive_path} --directory ${install_path}; sudo rm ${archive_path}",
require => Exec['bioperl-download']
}
pretty simple. But I have no idea where the problem is because I can't see what its doing. The provisioner is set to verbose mode, and here are the output lines for my module:
==> default: Notice: /Stage[main]/Bioperl/Exec[bioperl-download]/returns: executed successfully
==> default: Notice: /Stage[main]/Bioperl/Exec[bioperl-extract]/returns: executed successfully
==> default: Notice: /Stage[main]/Bioperl/Exec[bioperl-path]/returns: executed successfully
So all I know is it executed these three steps successfully. It doesn't tell me anything about whether the steps did their job properly or not. I know that it didn't download the archive to /usr/local/lib that directory, and that it didn't add an environment variable file to /usr/profile.d. Maybe the issue is the variables containing the directories are wrong. Maybe the variable containing the archives download URI is wrong. How can I find these things out?
UPDATE:
It turns out the module does work. But to improve the module (since I want to upload it to forge.puppetlabs.com, I tried implementing the changes suggested by Matt. Heres the new code:
file { 'bioperl-download':
path => "${archive_path}",
source => "http://cpan.metacpan.org/authors/id/C/CJ/CJFIELDS/${archive_name}",
ensure => "present"
}
exec { 'bioperl-extract':
command => "sudo /bin/tar zxvf ${archive_name}",
cwd => "${bioperl_target_dir}",
require => File['bioperl-download']
}
A problem: It gives me an error telling me that the source cannot be http://. I see in the docs that they do indeed allow http:// files as the source for the file resource. Maybe I'm using an older version of puppet?
I want to try out the puppet-archive module, but I'm not sure how I can set it as a required dependency. By that, I mean how I can make sure its installed first. Do I need to get my module to download the module from github and save it to the modules directory? Or is there a way to let puppet install it automatically? I added it as a dependency to the metadata.json file, but that doesn't install it. I know I can just get my module to download the package, but I was wondering what best practice for this is.
The initial problem you describe is acceptance testing. Verifying that the Puppet resources and code you wrote actually resulted in the desired end state you wanted is normally accomplished with Serverspec: http://serverspec.org/. For example, you can write a Puppet module to deploy an application, but you only know that Puppet did what you told it to, and not that the application actually successfully deployed. Note Serverspec is also what people generally use to solve this problem for Ansible and Chef also.
You can write a Serverspec test similar to the following to help test your module's end state:
describe file('/usr/local/lib/bioperl.tar.gz') do
it { expect(subject).to be_file }
end
describe file('/usr/profile.d/env_file') do
it { expect_subject).to be_file }
its(:content) { is_expected.to match(/env stuff/) }
end
However, your problem also seems to deal with debugging why your acceptance tests failed. For that, you need unit testing. This is normally solved with RSpec-Puppet: http://rspec-puppet.com/. I would show you how to write some tests for your situation, but I don't think you should be writing your Puppet module the way that you did, so it would render the unit tests irrelevant.
Instead, consider using a file resource with the source attribute and a HTTP URI to grab the tarball instead of an exec with wget: https://docs.puppet.com/puppet/latest/type.html#file-attribute-source. Also, you might want to consider using the Puppet archive module to assist you: https://forge.puppet.com/puppet/archive.
If you have questions on how to use these tools to provide unit and acceptance testing, or have questions on how to refactor your module, then don't hesitate to write followup questions on StackOverflow and we can help you.
I'll need to add a apt repository key to a bunch of ubuntu hosts using puppet.
Would a statement like this work for that?
exec {"add apt key for elastic":
command => "/usr/bin/curl https://packages.elasticsearch.org/GPG-KEY-elasticsearch | /usr/bin/apt-key add -",
}
thanks
Yes, this should work but this will also apply the same configuration whenever you rerun Puppet.
From exec docs:
Any command in an exec resource must be able to run multiple times without causing harm — that is, it must be idempotent. There are three main ways for an exec to be idempotent:
The command itself is already idempotent. (For example, apt-get update.)
The exec has an onlyif, unless, or creates attribute, which prevents Puppet from running the command unless some condition is met.
The exec has refreshonly => true, which only allows Puppet to run the command when some other resource is changed. (See the notes on refreshing below.)
I try and only use execs if I really have to. One of the reasons being that you have to code the exec so that it only runs when you want to. Instead, you can use the apt module. This will only place the key on the host if it does not already exist. The resource is under puppet control so will not be added on subsequent runs:
include apt
apt::key { 'elasticsearch':
id => '46095ACC8548582C1A2699A9D27D666CD88E42B4',
options => 'https://packages.elasticsearch.org/GPG-KEY-elasticsearch',
}