xcat-core/xCAT-OpenStack/chef-cookbooks/grizzly-xcat/cookbooks/runit

Description

Installs runit and provides the runit_service service resource for managing processes (services) under runit.

This cookbook does not use runit to replace system init, nor are there plans to do so.

For more information about runit:

• http://smarden.org/runit/

About Runit

In brief, Runit is a process supervision suite. It is simple to set up, and doesn't require complex shell scripts to be written to start processes running as system services.

To manage a process in runit, create a "service" directory that contains a "run" script. In this cookbook we refer to that directory as the sv_dir (see Attributes and Resource/Provider). That service directory is symbolically linked into runit's own service directory where its runsvdir program looks for processes to manage. See the runit documentation for detailed information on runit.

Supervised processes are analogous to services under other systems such as sysvinit or upstart.

Requirements

Platform:

• Debian/Ubuntu
• Gentoo
• RHEL

Attributes

See attributes/default.rb for defaults generated per platform.

• node['runit']['sv_bin'] - Full path to the sv binary.
• node['runit']['chpst_bin'] - Full path to the chpst binary.
• node['runit']['service_dir'] - Full path to the default "services" directory where enabled services are linked.
• node['runit']['sv_dir'] - Full path to the directory where service lives, which gets linked to service_dir.
• node['runit']['start'] - Command to start the runsvdir service
• node['runit']['stop] - Command to stop the runsvdir service
• node['runit']['reload'] - Command to reload the runsvdir service

Recipes

default

The default recipe installs runit and starts runsvdir to supervise the services in runit's service directory (e.g., /etc/service).

On RHEL family systems, it will build the runit RPM using Ian Meyer's runit RPM SPEC.

On Debian family systems, the runit packages are maintained by the runit author, Gerrit Pape, and the recipe will use that for installation.

On Gentoo, the runit ebuild package is installed.

Resource/Provider

This cookbook has a resource, runit_service, for managing services under runit. This service subclasses the Chef service resource.

This resource replaces the runit_service definition. See the CHANGELOG.md file in this cookbook for breaking change information and any actions you may need to take to update cookbooks using runit_service.

Actions:

• enable - enables the service, creating the required run scripts and symlinks. This is the default action.
• start - starts the service with sv start
• stop - stops the service with sv stop
• disable - stops the service with sv down and removes the service symlink
• restart - restarts the service with sv restart
• reload - reloads the service with sv force-reload
• once - starts the service with sv once.
• hup - sends the HUP signal to the service with sv hup
• cont - sends the CONT signal to the service
• term - sends the TERM signal to the service
• kill - sends the KILL signal to the service
• up - starts the service with sv up
• down - downs the service with sv down
• usr1 - sends the USR1 signal to the service with sv 1
• usr2 - sends the USR2 signal to the service with sv 2

Service management actions are taken with runit's "sv" program.

Read the sv(8) man page for more information on the sv program.

Parameter Attributes

The first three parameters, sv_dir, service_dir, and sv_bin will attempt to use the corresponding node attributes, and fall back to hardcoded default values that match the settings used on Debian platform systems.

Many of these parameters are only used in the :enable action.

• sv_dir - The base "service directory" for the services managed by the resource. By default, this will attempt to use the node['runit']['sv_dir'] attribute, and falls back to /etc/sv.
• service_dir - The directory where services are symlinked to be supervised by runsvdir. By default, this will attempt to use the node['runit']['service_dir'] attribute, and falls back to /etc/service.
• sv_bin - The path to the sv program binary. This will attempt to use the node['runit']['sv_bin'] attribute, and falls back to /usr/bin/sv.
• service_name - Name attribute. The name of the service. This will be used in the directory of the managed service in the sv_dir and service_dir.
• sv_templates - If true, the :enable action will create the service directory with the appropriate templates. Default is true. Set this to false if the service has a package that provides its own service directory. See Usage examples.
• options - Options passed as variables to templates, for compatibility with legacy runit service definition. Default is an empty hash.
• env - A hash of environment variables with their values as content used in the service's env directory. Default is an empty hash.
• log - Whether to start the service's logger with svlogd, requires a template sv-service_name-log-run.erb to configure the log's run script. Default is true.
• default_logger - Whether a default log/run script should be set up. If true, the default content of the run script will use svlogd to write logs to /var/log/service_name. Default is false.
• cookbook - A cookbook where templates are located instead of where the resource is used. Applies for all the templates in the enable action.
• finish - whether the service has a finish script, requires a template sv-service_name-finish.erb
• control - An array of signals to customize control of the service, see runsv man page on how to use this. This requires that each template be created with the name sv-service_name-signal.erb.
• owner - user that should own the templates created to enable the service
• group - group that should own the templates created to enable the service
• run_template_name - alternate filename of the run run script to use replacing service_name.
• log_template_name - alternate filename of the log run script to use replacing service_name.
• finish_script_template_name - alternate filename of the finish script to use, replacing service_name.
• control_template_names - a hash of control signals (see control above) and their alternate template name(s) replacing service_name.
• status_command - The command used to check the status of the service to see if it is enabled/running (if it's running, it's enabled). This hardcodes the location of the sv program to /usr/bin/sv due to the aforementioned cookbook load order.
• restart_on_update - Whether the service should be restarted when the run script is updated. Defaults to true. Set to false if the service shouldn't be restarted when the run script is updated.

Unlike previous versions of the cookbook using the runit_service definition, the runit_service resource can be notified. See Usage examples below.

Usage

To get runit installed on supported platforms, use recipe[runit]. Once it is installed, use the runit_service resource to set up services to be managed by runit.

In order to use the runit_service resource in your cookbook(s), each service managed will also need to have sv-service_name-run.erb and sv-service_name-log-run.erb templates created. If the log parameter is false, the log run script isn't created. If the log parameter is true, and default_logger is also true, the log run script will be created with the default content:

#!/bin/sh
exec svlogd -tt /var/log/service_name

Examples

These are example use cases of the runit_service resource described above. There are others in the runit_test cookbook that is included in the git repository.

Default Example

This example uses all the defaults in the :enable action to set up the service.

We'll set up chef-client to run as a service under runit, such as is done in the chef-client cookbook. This example will be more simple than in that cookbook. First, create the required run template, chef-client/templates/default/sv-chef-client-run.erb.

#!/bin/sh
exec 2>&1
exec /usr/bin/env chef-client -i 1800 -s 30

Then create the required log/run template, chef-client/templates/default/sv-chef-client-log-run.erb.

#!/bin/sh
exec svlogd -tt ./main

Note This will cause output of the running process to go to /etc/sv/chef-client/log/main/current. Some people may not like this, see the following example. This is preserved for compatibility reasons.

Finally, set up the service in the recipe with:

runit_service "chef-client"

Default Logger Example

To use a default logger with svlogd which will log to /var/log/chef-client/current, instead, use the default_logger option.

runit_service "chef-client" do
  default_logger true
end

No Log Service

If there isn't an appendant log service, set log to false, and the log/run script won't be created.

runit_service "no-svlog" do
  log false
end

Finish Script

To create a service that has a finish script in its service directory, set the finish parameter to true, and create a sv-finisher-finish.erb template.

runit_service "finisher" do
  finish true
end

This will create /etc/sv/finisher/finish.

Alternate service directory

If the service directory for the managed service isn't the sv_dir (/etc/sv), then specify it:

runit_service "custom_service" do
  sv_dir "/etc/custom_service/runit"
end

No Service Directory

If the service to manage has a package that provides its service directory, such as git-daemon on Debian systems, set sv_templates to false.

package "git-daemon-run"

runit_service "git-daemon" do
  sv_templates false
end

This will create the service symlink in /etc/service, but it will not manage any templates in the service directory.

User Controlled Services

To set up services controlled by a non-privileged user, we follow the recommended configuration in the runit documentation (Is it possible to allow a user other than root to control a service?).

Suppose the user's name is floyd, and floyd wants to run floyds-app. Assuming that the floyd user and group are already managed with Chef, create a runsvdir-floyd runit_service.

runit_service "runsvdir-floyd"

Create the sv-runsvdir-floyd-log-run.erb template, or add log false. Also create the sv-runsvdir-floyd-run.erb with the following content:

#!/bin/sh
exec 2>&1
exec chpst -ufloyd runsvdir /home/floyd/service

Next, create the runit_service resource for floyd's app:

runit_service "floyds-app" do
  sv_dir "/home/floyd/sv"
  service_dir "/home/floyd/service"
  owner "floyd"
  group "floyd"
end

And now floyd can manage the service with sv:

$ id
uid=1000(floyd) gid=1001(floyd) groups=1001(floyd)
$ sv stop /home/floyd/service/floyds-app/
ok: down: /home/floyd/service/floyds-app/: 0s, normally up
$ sv start /home/floyd/service/floyds-app/
ok: run: /home/floyd/service/floyds-app/: (pid 5287) 0s
$ sv status /home/floyd/service/floyds-app/
run: /home/floyd/service/floyds-app/: (pid 5287) 13s; run: log: (pid 4691) 726s

Options

Next, let's set up memcached under runit with some additional options using the options parameter. First, the memcached/templates/default/sv-memcached-run.erb template:

#!/bin/sh
exec 2>&1
exec chpst -u <%= @options[:user] %> /usr/bin/memcached -v -m <%= @options[:memory] %> -p <%= @options[:port] %>

Note that the script uses chpst (which comes with runit) to set the user option, then starts memcached on the specified memory and port (see below).

The log/run template, memcached/templates/default/sv-memcached-log-run.erb:

#!/bin/sh
exec svlogd -tt ./main

Finally, the runit_service in our recipe:

runit_service "memcached" do
  options({
    :memory => node[:memcached][:memory],
    :port => node[:memcached][:port],
    :user => node[:memcached][:user]}.merge(params)
  )
end

This is where the user, port and memory options used in the run template are used.

Notifying Runit Services

In previous versions of this cookbook where the definition was used, it created a service resource that could be notified. With the runit_service resource, recipes need to use the full resource name. For example:

runit_service "my-service"

template "/etc/my-service.conf" do
  notifies :restart, "runit_service[my-service]"
end

Because the resource implements actions for various commands that sv can send to the service, any of those actions could be used for notification. For example, chef-client supports triggering a Chef run with a USR1 signal.

template "/tmp/chef-notifier" do
  notifies :usr1, "runit_service[chef-client]"
end

For older implementations of services that used runit_service as a definition, but may support alternate service styles, use a conditional, such as based on an attribute:

service_to_notify = case node['nginx']['init_style']
                    when "runit"
                      "runit_service[nginx]"
                    else
                      "service[nginx]"
                    end

template "/etc/nginx/nginx.conf" do
  notifies :restart, service_to_notify
end

More Examples

For more examples, see the runit_test cookbook's service recipe in the git repository.

Testing

This cookbook has tests in the GitHub repository. To run the tests:

git clone git://github.com/opscode-cookbooks/runit.git
cd runit
bundle install

There are two kinds of tests, unit tests and integration tests.

Unit Tests

The resource/provider code is unit tested with rspec. To run these tests, use rake:

bundle exec rake spec

Integration Tests

Integration tests are setup to run under minitest-chef. They are automatically run under test kitchen.

bundle exec kitchen test

This tests the default recipe ("default" configuration), and various uses of the runit_service resource ("service" configuration).

License and Author

Author:: Adam Jacob adam@opscode.com Author:: Joshua Timberman joshua@opscode.com

Copyright:: 2008-2013, Opscode, Inc

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.