Communcation: MyApp-ChefClient-ChefSrver-ChefClients

[Leonid_Medvedev]

Dear all.

I have one interest question. Please answer is it possible or not? Please
advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example 100-1000
  times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or field
   from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of the
   trigger.

Thanks&Regards
Leonid

[Ranjib]

Do It
Its possible
"The Chef Client has to get trigger from MySDK (it can be alarm or field
from the database) and sends the trigger to Chef Server (second host)."

• MySDK has to use mco, or pushy or ansible or blender or rundeck like
  tool to do this (orchestration engine).

Chef Server does not support plugging in custom modules (last time i
checked there were talks about http middlewares, but nothing concrete),

I'll suggest using chef server as artifact store (cookbooks, roles ,
databags etc) and metadata source (chef search, nodes etc), but not as a
messaging system (i.e. chef server triggering client runs), its a different
service , you can consolidate them in one box but still they are different.

I have used MCollective[1] to do the same, now im using Serf (fleet wide
triggers, and all other automated triggers) and SSH agent (for on demand
runs) via blender[2]. You can do same with pushy, but i dont know the full
feature set there.

In this scenario, you'll use chef event handlers to drop serf events or
mco calls to indicate state change (like run failed or node converged or a
particular file has changed), these event can have payloads. Your app
should subscribe these events (like serf handler, for mco u'll use
exchanges, topics etc AMQP primitives). Your app can talk to chef server
using the ruby or java or go api (whatever language you choose), chef'
client's REST abstraction is all you need to talk to chef server.

It will easier to discuss an actual use case (e.g vm provisioning via web
service), then we can break down the use case into tasks, and then provide
exact examples and compare them side by side

cheers
ranjib

[1]MCollective: http://puppetlabs.com/mcollective
[2]Blender: GitHub - PagerDuty/blender: A modular orchestration engine
[3]Serf :https://serfdom.io/

On Tue, Feb 3, 2015 at 9:07 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Dear all.

I have one interest question. Please answer is it possible or not? Please
advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example 100-1000
  times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or field
   from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of the
   trigger.

Thanks&Regards
Leonid

[Leonid_Medvedev]

Hello Ranjib Dey

Thanks a lot. Sorry for the delay with answer.

Unfortunately we are not familiar with these frameworks: mco, pushy,
ansible, blender or rundeck. But we will investigate them; you understand
it is not easy to use external additional products.

But I have several additional questions:

1. Is it possible to use "Chef Push Jobs" (
   https://docs.chef.io/push_jobs.html). I would like to install this service
   on the same host with MyApp. And the question for these case - you wrote: "Your
   app can talk to chef server using the ruby or java or go api", please
   clarify or send the link with explanation.

2. Next question. Is it possible to extend Chef Client - for example it
   should open DB and read/write some fields in a table. Please also clarify.

3. Last question. Can we use Chef client as retransmitter of messages to
   Chef Server?

Thanks a lot again and again :).

Leonid.

2015-02-03 23:40 GMT+02:00 Ranjib Dey dey.ranjib@gmail.com:

Do It
Its possible
"The Chef Client has to get trigger from MySDK (it can be alarm or field
from the database) and sends the trigger to Chef Server (second host)."

• MySDK has to use mco, or pushy or ansible or blender or rundeck like
  tool to do this (orchestration engine).

Chef Server does not support plugging in custom modules (last time i
checked there were talks about http middlewares, but nothing concrete),

I'll suggest using chef server as artifact store (cookbooks, roles ,
databags etc) and metadata source (chef search, nodes etc), but not as a
messaging system (i.e. chef server triggering client runs), its a different
service , you can consolidate them in one box but still they are different.

I have used MCollective[1] to do the same, now im using Serf (fleet wide
triggers, and all other automated triggers) and SSH agent (for on demand
runs) via blender[2]. You can do same with pushy, but i dont know the full
feature set there.

In this scenario, you'll use chef event handlers to drop serf events or
mco calls to indicate state change (like run failed or node converged or a
particular file has changed), these event can have payloads. Your app
should subscribe these events (like serf handler, for mco u'll use
exchanges, topics etc AMQP primitives). Your app can talk to chef server
using the ruby or java or go api (whatever language you choose), chef'
client's REST abstraction is all you need to talk to chef server.

It will easier to discuss an actual use case (e.g vm provisioning via web
service), then we can break down the use case into tasks, and then provide
exact examples and compare them side by side

cheers
ranjib

[1]MCollective: http://puppetlabs.com/mcollective
[2]Blender: GitHub - PagerDuty/blender: A modular orchestration engine
[3]Serf :https://serfdom.io/

On Tue, Feb 3, 2015 at 9:07 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Dear all.

I have one interest question. Please answer is it possible or not? Please
advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example 100-1000
  times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or
   field from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of
   the trigger.

Thanks&Regards
Leonid

[kritivagop01]

hi,

i have alternative solution :

chef server will have all cookbooks and other information.

chef workstation used to maintain all cookbooks and uploading to server

chef client to receive those cookbooks and maintained by chef server.

chef workstation,we can upload cookbooks and can use knife ssh to ask all
chef client for the execute chef-client and get the update in one command.

thanks,
K.Gopalakrishnan

On Thu, Feb 5, 2015 at 1:36 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Hello Ranjib Dey

Thanks a lot. Sorry for the delay with answer.

Unfortunately we are not familiar with these frameworks: mco, pushy,
ansible, blender or rundeck. But we will investigate them; you understand
it is not easy to use external additional products.

But I have several additional questions:

1. Is it possible to use "Chef Push Jobs" (
   https://docs.chef.io/push_jobs.html). I would like to install this
   service on the same host with MyApp. And the question for these case - you
   wrote: "Your app can talk to chef server using the ruby or java or go api",
   please clarify or send the link with explanation.

2. Next question. Is it possible to extend Chef Client - for example it
   should open DB and read/write some fields in a table. Please also clarify.

3. Last question. Can we use Chef client as retransmitter of messages to
   Chef Server?

Thanks a lot again and again :).

Leonid.

2015-02-03 23:40 GMT+02:00 Ranjib Dey dey.ranjib@gmail.com:

Do It
Its possible
"The Chef Client has to get trigger from MySDK (it can be alarm or field
from the database) and sends the trigger to Chef Server (second host)."

• MySDK has to use mco, or pushy or ansible or blender or rundeck like
  tool to do this (orchestration engine).

Chef Server does not support plugging in custom modules (last time i
checked there were talks about http middlewares, but nothing concrete),

I'll suggest using chef server as artifact store (cookbooks, roles ,
databags etc) and metadata source (chef search, nodes etc), but not as a
messaging system (i.e. chef server triggering client runs), its a different
service , you can consolidate them in one box but still they are different.

I have used MCollective[1] to do the same, now im using Serf (fleet wide
triggers, and all other automated triggers) and SSH agent (for on demand
runs) via blender[2]. You can do same with pushy, but i dont know the full
feature set there.

In this scenario, you'll use chef event handlers to drop serf events or
mco calls to indicate state change (like run failed or node converged or a
particular file has changed), these event can have payloads. Your app
should subscribe these events (like serf handler, for mco u'll use
exchanges, topics etc AMQP primitives). Your app can talk to chef server
using the ruby or java or go api (whatever language you choose), chef'
client's REST abstraction is all you need to talk to chef server.

It will easier to discuss an actual use case (e.g vm provisioning via web
service), then we can break down the use case into tasks, and then provide
exact examples and compare them side by side

cheers
ranjib

[1]MCollective: http://puppetlabs.com/mcollective
[2]Blender: GitHub - PagerDuty/blender: A modular orchestration engine
[3]Serf :https://serfdom.io/

On Tue, Feb 3, 2015 at 9:07 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Dear all.

I have one interest question. Please answer is it possible or not?
Please advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example 100-1000
  times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or
   field from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of
   the trigger.

Thanks&Regards
Leonid

[Ranjib]

1. pushy is chef push jobs . if your app is written in ruby you can use
   the chef library itself to access chef server, it provides a CRUD api for
   all domain objects(node, role, environment etc), a search query api etc. If
   you are writing applications in go the go-chef can be used to do similar
   actions. Noah one of our awesome community member wrote python binding for
   chef, jcloud has a java binding also (and i think an android app is also
   there). All of these library allows you to do the communication with chef
   server rest API (i.e. auth headers, http, json handling etc). Depending
   upon what stack you are choosing to your custom SDK you can choose one of
   these, to those crud stuff or search query.

2. You can extend chef-client in many ways, some popular ones are:
   a) cookbook -recipes
   b) lwrp/hwrp - resource providers
   a) report and exception handlers
   b) event handlers - execute your custom logic during certain time in chef
   run life cycle.
   c) custom knife plugins - build custom CLI tools that involves talking with
   chef server

Recipes and cookbooks are actually an extension of chef (since they are
eval-ed).
The example you have given can be done by standard resource provider itself
, the database cookbook offers user and db as resources.
If the intention of db alteration means a configuration, and you want to
keep it consistent across your infra you can offer them as
resource/providers. Depending upon what task you want to do you have to
choose the extension mechanism. Like earlier someone was asking about
displaying version specific recipe usage across the nodes. Knife will be
perfect for the display/cli part, and an event handler can gather the
custom data and save back as a node attribute

3. chef client can only post back data about itself. So it can save any
   update about itself. I wont call this as event transmission though. Neither
   i am aware of anyway to retransmit chef-server changes via chef-client.

Note: all these experience is based on opensource chef server, push jobs
and other chef-server add-on might be providing more stuff, but i have
never used them.

Most of the earlier orchestration frameworks i have mentioned are
opensource :-), as long as they solve new challenges, that can not be
easily done by existing solutions, i think its fine, as otherwise you'll
end up rolling your own any way.

[1]go-chef · GitHub
[2]GitHub - coderanger/pychef: Python library to interact with the Chef server API
[3]
https://github.com/jclouds/jclouds/blob/d3c1e2eab4bd71ecdf2ebfcd73e5d28c835398cd/apis/chef/src/main/java/org/jclouds/chef/ChefApi.java

On Wed, Feb 4, 2015 at 12:06 PM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Hello Ranjib Dey

Thanks a lot. Sorry for the delay with answer.

Unfortunately we are not familiar with these frameworks: mco, pushy,
ansible, blender or rundeck. But we will investigate them; you understand
it is not easy to use external additional products.

But I have several additional questions:

1. Is it possible to use "Chef Push Jobs" (
   https://docs.chef.io/push_jobs.html). I would like to install this
   service on the same host with MyApp. And the question for these case - you
   wrote: "Your app can talk to chef server using the ruby or java or go api",
   please clarify or send the link with explanation.

2. Next question. Is it possible to extend Chef Client - for example it
   should open DB and read/write some fields in a table. Please also clarify.

3. Last question. Can we use Chef client as retransmitter of messages to
   Chef Server?

Thanks a lot again and again :).

Leonid.

2015-02-03 23:40 GMT+02:00 Ranjib Dey dey.ranjib@gmail.com:

Do It
Its possible
"The Chef Client has to get trigger from MySDK (it can be alarm or field
from the database) and sends the trigger to Chef Server (second host)."

• MySDK has to use mco, or pushy or ansible or blender or rundeck like
  tool to do this (orchestration engine).

Chef Server does not support plugging in custom modules (last time i
checked there were talks about http middlewares, but nothing concrete),

I'll suggest using chef server as artifact store (cookbooks, roles ,
databags etc) and metadata source (chef search, nodes etc), but not as a
messaging system (i.e. chef server triggering client runs), its a different
service , you can consolidate them in one box but still they are different.

I have used MCollective[1] to do the same, now im using Serf (fleet wide
triggers, and all other automated triggers) and SSH agent (for on demand
runs) via blender[2]. You can do same with pushy, but i dont know the full
feature set there.

In this scenario, you'll use chef event handlers to drop serf events or
mco calls to indicate state change (like run failed or node converged or a
particular file has changed), these event can have payloads. Your app
should subscribe these events (like serf handler, for mco u'll use
exchanges, topics etc AMQP primitives). Your app can talk to chef server
using the ruby or java or go api (whatever language you choose), chef'
client's REST abstraction is all you need to talk to chef server.

It will easier to discuss an actual use case (e.g vm provisioning via web
service), then we can break down the use case into tasks, and then provide
exact examples and compare them side by side

cheers
ranjib

[1]MCollective: http://puppetlabs.com/mcollective
[2]Blender: GitHub - PagerDuty/blender: A modular orchestration engine
[3]Serf :https://serfdom.io/

On Tue, Feb 3, 2015 at 9:07 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Dear all.

I have one interest question. Please answer is it possible or not?
Please advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example 100-1000
  times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or
   field from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of
   the trigger.

Thanks&Regards
Leonid

[Ranjib]

if this combination works for you, then you should stick to it :0-). I use
knife ssh extensively and i love it. But this involves chef-workstation as
part of the workflow. Sometime thats not what i want. Also ssh transport is
lot more chatty (loads of PSHs). SSH auth setup is an aprior step. Sometime
this assumptions are valid, and knife-ssh works fine, other times you'll
need alternatives

But complex workflows, as i mentioned in the earlier email, is difficult
with knife ssh. spicewasel is popular for the same reason, as it ties knife
commands into a single file.

I recently published the knife extension for blender-chef [1], you can give
it a try just to check how its different from knife-ssh (similar can be
done via ansible, mco etc as well).

[1]GitHub - PagerDuty/blender-chef: Chef search based host discovery for blender.

On Wed, Feb 4, 2015 at 6:03 PM, kritivagop01 . krithiva.gopal@gmail.com
wrote:

hi,

i have alternative solution :

chef server will have all cookbooks and other information.

chef workstation used to maintain all cookbooks and uploading to server

chef client to receive those cookbooks and maintained by chef server.

chef workstation,we can upload cookbooks and can use knife ssh to ask all
chef client for the execute chef-client and get the update in one command.

thanks,
K.Gopalakrishnan

On Thu, Feb 5, 2015 at 1:36 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Hello Ranjib Dey

Thanks a lot. Sorry for the delay with answer.

Unfortunately we are not familiar with these frameworks: mco, pushy,
ansible, blender or rundeck. But we will investigate them; you understand
it is not easy to use external additional products.

But I have several additional questions:

1. Is it possible to use "Chef Push Jobs" (
   https://docs.chef.io/push_jobs.html). I would like to install this
   service on the same host with MyApp. And the question for these case - you
   wrote: "Your app can talk to chef server using the ruby or java or go api",
   please clarify or send the link with explanation.

2. Next question. Is it possible to extend Chef Client - for example it
   should open DB and read/write some fields in a table. Please also clarify.

3. Last question. Can we use Chef client as retransmitter of messages to
   Chef Server?

Thanks a lot again and again :).

Leonid.

2015-02-03 23:40 GMT+02:00 Ranjib Dey dey.ranjib@gmail.com:

Do It
Its possible
"The Chef Client has to get trigger from MySDK (it can be alarm or field
from the database) and sends the trigger to Chef Server (second host)."

• MySDK has to use mco, or pushy or ansible or blender or rundeck like
  tool to do this (orchestration engine).

Chef Server does not support plugging in custom modules (last time i
checked there were talks about http middlewares, but nothing concrete),

I'll suggest using chef server as artifact store (cookbooks, roles ,
databags etc) and metadata source (chef search, nodes etc), but not as a
messaging system (i.e. chef server triggering client runs), its a different
service , you can consolidate them in one box but still they are different.

I have used MCollective[1] to do the same, now im using Serf (fleet wide
triggers, and all other automated triggers) and SSH agent (for on demand
runs) via blender[2]. You can do same with pushy, but i dont know the full
feature set there.

In this scenario, you'll use chef event handlers to drop serf events or
mco calls to indicate state change (like run failed or node converged or a
particular file has changed), these event can have payloads. Your app
should subscribe these events (like serf handler, for mco u'll use
exchanges, topics etc AMQP primitives). Your app can talk to chef server
using the ruby or java or go api (whatever language you choose), chef'
client's REST abstraction is all you need to talk to chef server.

It will easier to discuss an actual use case (e.g vm provisioning via
web service), then we can break down the use case into tasks, and then
provide exact examples and compare them side by side

cheers
ranjib

[1]MCollective: http://puppetlabs.com/mcollective
[2]Blender: GitHub - PagerDuty/blender: A modular orchestration engine
[3]Serf :https://serfdom.io/

On Tue, Feb 3, 2015 at 9:07 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Dear all.

I have one interest question. Please answer is it possible or not?
Please advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example
  100-1000 times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or
   field from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of
   the trigger.

Thanks&Regards
Leonid

[Leonid_Medvedev]

Hi all.

Sorry for the delay - investigating.
After investigation the really interesting suggestions I see two cases
which will be investigated deeply. I will describe them and ask your
opinions.

Case 1:

• MyApp. will have to protocols: REST API (for receiving responses)
  and Webhooks
  (PUSH notification for sending requests) for integration with Configuration
  Managers (CM) Chef/Puppet/....
  Briefly the sequence of integration with CM:

1. MyApp. (from host 1) prepares request - create Push notification.
2. CM Server receives Push notification.
3. CM Server performs the received request.
4. CM Server prepares response for MyApp - create PUSH (REST API).
5. MyApp receives REST API response from CM Server.

Only one big question: we should develop some "bridge" which will
receive PUSH Notification and re-transmit them to CM Server. After that
this "bridge" has to receive data from CM Server and re-transmit as REST
API for MyApp.
Do you have ideas about "case 1"?

Case 2:

• MCollective. This is smart solution but it is only for Chef/Puppet/Salt.
  As I understand MCollective can help integrate (re-transmit data) MyApp
  with CM (Chef/Puppet/Salt).

Thanks for cooperation.
Leonid

2015-02-05 6:12 GMT+02:00 Ranjib Dey dey.ranjib@gmail.com:

1. pushy is chef push jobs . if your app is written in ruby you can
   use the chef library itself to access chef server, it provides a CRUD api
   for all domain objects(node, role, environment etc), a search query api
   etc. If you are writing applications in go the go-chef can be used to do
   similar actions. Noah one of our awesome community member wrote python
   binding for chef, jcloud has a java binding also (and i think an android
   app is also there). All of these library allows you to do the communication
   with chef server rest API (i.e. auth headers, http, json handling etc).
   Depending upon what stack you are choosing to your custom SDK you can
   choose one of these, to those crud stuff or search query.

2. You can extend chef-client in many ways, some popular ones are:
   a) cookbook -recipes
   b) lwrp/hwrp - resource providers
   a) report and exception handlers
   b) event handlers - execute your custom logic during certain time in chef
   run life cycle.
   c) custom knife plugins - build custom CLI tools that involves talking
   with chef server

Recipes and cookbooks are actually an extension of chef (since they are
eval-ed).
The example you have given can be done by standard resource provider
itself , the database cookbook offers user and db as resources.
If the intention of db alteration means a configuration, and you want to
keep it consistent across your infra you can offer them as
resource/providers. Depending upon what task you want to do you have to
choose the extension mechanism. Like earlier someone was asking about
displaying version specific recipe usage across the nodes. Knife will be
perfect for the display/cli part, and an event handler can gather the
custom data and save back as a node attribute

3. chef client can only post back data about itself. So it can save any
   update about itself. I wont call this as event transmission though. Neither
   i am aware of anyway to retransmit chef-server changes via chef-client.

Note: all these experience is based on opensource chef server, push jobs
and other chef-server add-on might be providing more stuff, but i have
never used them.

Most of the earlier orchestration frameworks i have mentioned are
opensource :-), as long as they solve new challenges, that can not be
easily done by existing solutions, i think its fine, as otherwise you'll
end up rolling your own any way.

[1]go-chef · GitHub
[2]GitHub - coderanger/pychef: Python library to interact with the Chef server API
[3]
https://github.com/jclouds/jclouds/blob/d3c1e2eab4bd71ecdf2ebfcd73e5d28c835398cd/apis/chef/src/main/java/org/jclouds/chef/ChefApi.java

On Wed, Feb 4, 2015 at 12:06 PM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Hello Ranjib Dey

Thanks a lot. Sorry for the delay with answer.

Unfortunately we are not familiar with these frameworks: mco, pushy,
ansible, blender or rundeck. But we will investigate them; you understand
it is not easy to use external additional products.

But I have several additional questions:

1. Is it possible to use "Chef Push Jobs" (
   https://docs.chef.io/push_jobs.html). I would like to install this
   service on the same host with MyApp. And the question for these case - you
   wrote: "Your app can talk to chef server using the ruby or java or go api",
   please clarify or send the link with explanation.

2. Next question. Is it possible to extend Chef Client - for example it
   should open DB and read/write some fields in a table. Please also clarify.

3. Last question. Can we use Chef client as retransmitter of messages to
   Chef Server?

Thanks a lot again and again :).

Leonid.

2015-02-03 23:40 GMT+02:00 Ranjib Dey dey.ranjib@gmail.com:

Do It
Its possible
"The Chef Client has to get trigger from MySDK (it can be alarm or field
from the database) and sends the trigger to Chef Server (second host)."

• MySDK has to use mco, or pushy or ansible or blender or rundeck like
  tool to do this (orchestration engine).

Chef Server does not support plugging in custom modules (last time i
checked there were talks about http middlewares, but nothing concrete),

I'll suggest using chef server as artifact store (cookbooks, roles ,
databags etc) and metadata source (chef search, nodes etc), but not as a
messaging system (i.e. chef server triggering client runs), its a different
service , you can consolidate them in one box but still they are different.

I have used MCollective[1] to do the same, now im using Serf (fleet wide
triggers, and all other automated triggers) and SSH agent (for on demand
runs) via blender[2]. You can do same with pushy, but i dont know the full
feature set there.

In this scenario, you'll use chef event handlers to drop serf events or
mco calls to indicate state change (like run failed or node converged or a
particular file has changed), these event can have payloads. Your app
should subscribe these events (like serf handler, for mco u'll use
exchanges, topics etc AMQP primitives). Your app can talk to chef server
using the ruby or java or go api (whatever language you choose), chef'
client's REST abstraction is all you need to talk to chef server.

It will easier to discuss an actual use case (e.g vm provisioning via
web service), then we can break down the use case into tasks, and then
provide exact examples and compare them side by side

cheers
ranjib

[1]MCollective: http://puppetlabs.com/mcollective
[2]Blender: GitHub - PagerDuty/blender: A modular orchestration engine
[3]Serf :https://serfdom.io/

On Tue, Feb 3, 2015 at 9:07 AM, Leonid Medvedev bearlionalex@gmail.com
wrote:

Dear all.

I have one interest question. Please answer is it possible or not?
Please advise what is the best choice from your point of view.

The description in details (the picture is in attachment):

1. Hardware configuration:

• The first host has: MySDK and Chef Client;
• Second host has Chef Server;
• other Chef Clients installed on a lot of hosts (for example
  100-1000 times).

2. MySDK installed on the same host with Chef Client.
3. The Chef Client has to get trigger from MySDK (it can be alarm or
   field from the database) and sends the trigger to Chef Server (second host).
4. The Chef Server sends a request to other Chef Clients which have to
   perform cookbooks according received trigger.
5. Chef Clients perform cookbooks and notify Chef Server about results.
6. Chef Server sends this result to the Chef Client (first host).
7. Chef Client informs MySDK (they are on first host) about results of
   the trigger.

Thanks&Regards
Leonid