[openstack-dev] [heat] Sofware Config progress

Prasad Vellanki prasad.vellanki at oneconvergence.com
Thu Jan 9 01:57:43 UTC 2014


Clint & Steve
One scenario we are trying to see is whether and how Heat software-config
enables  deployment of  images available from third party as virtual
appliances,  providing network, security or acceleration capabilities. The
vendor in some cases might not allow rebuilding and/or  may not have the
cloud init capability.Sometimes changes to the image could run into issues
with licensing. Bootstrapping in such situations is generally done via rest
api or ssh once the appliance boots up where one can bootstrap it further.

We are looking at how to automate deployment of such service functions
using new configuration and deployment  model in Heat which we really like.

One option is that software-config can provide an option in Heat to trigger
bootstrapping that can be done from outside rather than inside,  as done by
 cloud-init, and does bootstrapping of appliances using ssh and/or rest.

Another option is there could be an agent outside that recognizes this kind
of service coming up and then inform Heat  to go to next state to configure
the deployed resource. This is more like a proxy model.

thanks
prasadv



On Tue, Jan 7, 2014 at 11:40 AM, Clint Byrum <clint at fewbar.com> wrote:

> I'd say it isn't so much cloud-init that you need, but "some kind
> of bootstrapper". The point of hot-software-config is to help with
> in-instance orchestration. That's not going to happen without some way
> to push the desired configuration into the instance.
>
> Excerpts from Susaant Kondapaneni's message of 2014-01-07 11:16:16 -0800:
> > We work with images provided by vendors over which we do not always have
> > control. So we are considering the cases where vendor image does not come
> > installed with cloud-init. Is there a way to support heat software config
> > in such scenarios?
> >
> > Thanks
> > Susaant
> >
> > On Mon, Jan 6, 2014 at 4:47 PM, Steve Baker <sbaker at redhat.com> wrote:
> >
> > >  On 07/01/14 06:25, Susaant Kondapaneni wrote:
> > >
> > >  Hi Steve,
> > >
> > >  I am trying to understand the software config implementation. Can you
> > > clarify the following:
> > >
> > >  i. To use Software config and deploy in a template, instance resource
> > > MUST always be accompanied by user_data. User_data should specify how
> to
> > > bootstrap CM tool and signal it. Is that correct?
> > >
> > >   Yes, currently the user_data contains cfn-init formatted metadata
> which
> > > tells os-collect-config how to poll for config changes. What happens
> when
> > > new config is fetched depends on the os-apply-config templates and
> > > os-refresh-config scripts which are already on that image (or set up
> with
> > > cloud-init).
> > >
> > >  ii. Supposing we were to use images which do not have cloud-init
> > > packaged in them, (and a custom CM tool that won't require
> bootstrapping on
> > > the instance itself), can we still use software config and deploy
> resources
> > > to deploy software on such instances?
> > >
> > >   Currently os-collect-config is more of a requirement than cloud-init,
> > > but as Clint said cloud-init does a good job of boot config so you'll
> need
> > > to elaborate on why you don't want to use it.
> > >
> > >  iii. If ii. were possible who would signal the deployment resource to
> > > indicate that the instance is ready for the deployment?
> > >
> > > os-collect-config polls for the deployment data, and triggers the
> > > resulting deployment/config changes. One day this may be performed by a
> > > different agent like the unified agent that has been discussed.
> Currently
> > > os-collect-collect polls via a heat-api-cfn metadata call. This too
> may be
> > > done in any number of ways in the future such as messaging or
> long-polling.
> > >
> > > So you *could* consume the supplied user_data to know what to poll for
> > > subsequent config changes without cloud-init or os-collect-config, but
> you
> > > would have to describe what you're doing in detail for us to know if
> that
> > > sounds like a good idea.
> > >
> > >
> > >
> > >  Thanks
> > > Susaant
> > >
> > >
> > > On Fri, Dec 13, 2013 at 3:46 PM, Steve Baker <sbaker at redhat.com>
> wrote:
> > >
> > >>  I've been working on a POC in heat for resources which perform
> software
> > >> configuration, with the aim of implementing this spec
> > >>
> https://wiki.openstack.org/wiki/Heat/Blueprints/hot-software-config-spec
> > >>
> > >> The code to date is here:
> > >> https://review.openstack.org/#/q/topic:bp/hot-software-config,n,z
> > >>
> > >> What would be helpful now is reviews which give the architectural
> > >> approach enough of a blessing to justify fleshing this POC out into a
> ready
> > >> to merge changeset.
> > >>
> > >> Currently it is possible to:
> > >> - create templates containing OS::Heat::SoftwareConfig and
> > >> OS::Heat::SoftwareDeployment resources
> > >> - deploy configs to OS::Nova::Server, where the deployment resource
> > >> remains in an IN_PROGRESS state until it is signalled with the output
> values
> > >> - write configs which execute shell scripts and report back with
> output
> > >> values that other resources can have access to.
> > >>
> > >> What follows is an overview of the architecture and implementation to
> > >> help with your reviews.
> > >>
> > >> REST API
> > >> ========
> > >> Like many heat resources, OS::Heat::SoftwareConfig and
> > >> OS::Heat::SoftwareDeployment are backed by "real" resources that are
> > >> invoked via a REST API. However in this case, the API that is called
> is
> > >> heat itself.
> > >>
> > >> The REST API for these resources really just act as structured storage
> > >> for config and deployments, and the entities are managed via the REST
> paths
> > >> /{tenant_id}/software_configs and /{tenant_id}/software_deployments:
> > >>
> > >> <
> https://review.openstack.org/#/c/58878/7/heat/api/openstack/v1/__init__.py
> >
> > >> https://review.openstack.org/#/c/58878/
> > >> RPC layer of REST API:
> > >> https://review.openstack.org/#/c/58877/
> > >> DB layer of REST API:
> > >> https://review.openstack.org/#/c/58876
> > >> heatclient lib access to REST API:
> > >> https://review.openstack.org/#/c/58885
> > >>
> > >> This data could be stored in a less structured datastore like swift,
> but
> > >> this API has a couple of important implementation details which I
> think
> > >> justify it existing:
> > >> - SoftwareConfig resources are immutable once created. There is no
> update
> > >> API to modify an existing config. This gives confidence that a config
> can
> > >> have a long lifecycle without changing, and a certainty of what
> exactly is
> > >> deployed on a server with a given config.
> > >> - Fetching all the deployments and configs for a given server is an
> > >> operation done repeatedly throughout the lifecycle of the stack, so is
> > >> optimized to be able to do in a single operation. This is called by
> using
> > >> the deployments index API call,
> > >> /{tenant_id}/software_deployments?server_id=<server_id>. The
> resulting list
> > >> of deployments include the their associated config data[1].
> > >>
> > >> OS::Heat::SoftwareConfig resource
> > >> =================================
> > >> OS::Heat::SoftwareConfig can be used directly in a template, but it
> may
> > >> end be more frequently used in a resource provider template which
> provides
> > >> a resource aimed at a particular configuration management tool.
> > >>
> > >>
> http://docs-draft.openstack.org/79/58879/7/check/gate-heat-docs/911a250/doc/build/html/template_guide/openstack.html#OS::Heat::SoftwareConfig
> > >> The contents of the config property will depend on the CM tool being
> > >> used, but at least one value in the config map will be the actual
> script
> > >> that the CM tool invokes.  An inputs and outputs schema is also
> defined
> > >> here. The group property is used when the deployments data is actually
> > >> delivered to the server (more on that later).
> > >>
> > >> Since a config is immutable, any changes to a
> OS::Heat::SoftwareConfig on
> > >> stack update result in replacement.
> > >>
> > >> OS::Heat::SoftwareDeployment resource
> > >> =====================================
> > >> OS::Heat::SoftwareDeployment joins a OS::Heat::SoftwareConfig resource
> > >> with a OS::Nova::Server resource. It allows server-specific input
> values to
> > >> be specified that map to the OS::Heat::SoftwareConfig inputs schema.
> Output
> > >> values that are signaled to the deployment resource are exposed as
> resource
> > >> attributes, using the names specified in the outputs schema. The
> > >> OS::Heat::SoftwareDeployment resource remains in an IN_PROGRESS state
> until
> > >> it receives a signal (containing any outputs) from the server.
> > >>
> > >>
> http://docs-draft.openstack.org/79/58879/7/check/gate-heat-docs/911a250/doc/build/html/template_guide/openstack.html#OS::Heat::SoftwareDeployment
> > >>
> > >> A deployment has its own actions and statuses that are specific to
> what a
> > >> deployment does, and OS::Heat::SoftwareDeployment maps this to heat
> > >> resource statuses and actions:
> > >> actions:
> > >> DEPLOY -> CREATE
> > >> REDEPLOY -> UPDATE
> > >> UNDEPLOY -> DELETE
> > >>
> > >> status (these could use some bikeshedding):
> > >> WAITING -> IN_PROGRESS
> > >> RECEIVED -> COMPLETE
> > >> FAILED -> FAILED
> > >>
> > >> In the config outputs schema there is a special flag for
> error_output. If
> > >> the signal response contains any value for any of these error_output
> > >> outputs then the deployment resource is put into the FAILED state.
> > >>
> > >> The SoftwareDeployment class subclasses SignalResponder which means
> that
> > >> a SoftwareDeployment creates an associated user and ec2 keypair.
> Since the
> > >> SoftwareDeployment needs to use the resource_id for the deployment
> resource
> > >> uuid, the user_id needs to be stored in resource-date instead. This
> non-wip
> > >> change enables that:
> > >> https://review.openstack.org/#/c/61902/
> > >>
> > >> During create, the deployment REST API is polled until status goes
> from
> > >> WAITING to RECEIVED. When handle_signal is called, the deployment is
> > >> updated via the REST API to set the status to RECEIVED (or FAILED),
> along
> > >> with any output values that were received.
> > >>
> > >> One alarming consequence of having a deployments API is that any
> tenant
> > >> user can create a deployment for any heat-created nova server and that
> > >> software will be deployed to that server, which is, um, powerful.
> > >>
> > >> There will need to be a deployment policy (probably an
> OS::Nova::Server
> > >> property) which limits to scope of what deployments are allowed on
> that
> > >> server. This could default to deployments in the same stack, but could
> > >> still allow deployments from anywhere.
> > >>
> > >> OS::Nova::Server support
> > >> ========================
> > >> https://review.openstack.org/#/c/58880
> > >> A new user_data_format=SOFTWARE_CONFIG is currently used to denote
> that
> > >> this server is configured via software config deployments. Like
> > >> user_data_format=HEAT_CFNTOOLS, nova_utils.build_userdata is used to
> build
> > >> the cloud-init parts required to support software config. However like
> > >> user_data_format=RAW anything specified in user_data will be parsed as
> > >> cloud-init data. If user_data is multi-part data then the parts will
> be
> > >> appended to the parts created in nova_utils.build_userdata.
> > >>
> > >> The agent used currently is os-collect-config. This is typically
> > >> configured to poll for metadata from a particular heat resource via
> the CFN
> > >> API using the configured ec2 keypair. In the current implementation
> the
> > >> resource which is polled is the OS::Nova::Server itself, since this
> is the
> > >> only resource known to exist at server boot time (deployment resources
> > >> depend on server resources, so have not been created yet). The ec2
> keypair
> > >> comes from a user created implicitly with the server (similar to
> > >> SignalResponder resources). This means the template author doesn't
> need to
> > >> include User/AccessKey/AccessPolicy resources in their templates just
> to
> > >> enable os-collect-config metadata polling.
> > >>
> > >> Until now, polling the metadata for a resource just returns the
> metadata
> > >> which has been stored in the stack resource database. This
> implementation
> > >> changes metadata polling to actually query the deployments API to
> return
> > >> the latest deployments data. This means deployment state can be
> stored in
> > >> one place, and there is no need to keep various metadata stores
> updated
> > >> with any changed state.
> > >>
> > >> An actual template
> > >> ==================
> > >> http://paste.openstack.org/show/54988/
> > >> This template contains:
> > >> - a config resource
> > >> - 2 deployments which deploy that config with 2 different sets of
> inputs
> > >> - stack outputs which output the results of the deployments
> > >> - a server resource
> > >> - an os-refresh-config script delivered via cloud-config[2] which
> > >> executes config scripts with deployment inputs and signals outputs to
> the
> > >> provided webhook.
> > >>
> > >> /opt/stack/os-config-refresh/configure.d/55-heat-config-bash is a hook
> > >> specific for performing configuration via shell scripts, and only
> acts on
> > >> software config which has group=Heat::Shell. Each configuration
> management
> > >> tool will have its own hook, and will act on its own group namespace.
> Each
> > >> configuration management tool will also have its own way of passing
> inputs
> > >> and outputs. The hooks job is to invoke the CM tool with the given
> inputs
> > >> and script, then extract the outputs and signal heat.
> > >>
> > >> The server needs to have the CM tool and the hook already installed,
> > >> either by building a golden image or by using cloud-config during
> boot.
> > >>
> > >> Next steps
> > >> ==========
> > >> There is a lot left to do and I'd like to spread the development load.
> > >> What happens next entirely depends on feedback to this POC, but here
> is my
> > >> ideal scenario:
> > >> - any feedback which causes churn on many of the current changes I
> will
> > >> address
> > >> - a volunteer is found to take the REST API/RPC/DB/heatclient changes
> and
> > >> make them ready to merge
> > >> - we continue to discuss and refine the resources, the changes to
> > >> OS::Nova::Server, and the example shell hook
> > >> - volunteers write hooks for different CM tools, Chef and Puppet hooks
> > >> will need to be attempted soon to validate this approach.
> > >>
> > >> Vaguely related changes include:
> > >> - Some solution for specifying cloud-init config, either the intrinsic
> > >> functions or cloud-init heat resources
> > >> - Some heatclient file inclusion mechanism - writing that python hook
> in
> > >> a heat yaml template was a bit painful ;)
> > >>
> > >> Trying for yourself
> > >> ===================
> > >> - Using diskimage-builder, create an ubuntu image with
> > >> tripleo-image-elements os-apply-config, os-refresh-config and
> > >> os-collect-config
> > >> - Create a local heat branch containing
> > >> https://review.openstack.org/#/q/topic:bp/cloud-init-resource,n,z and
> > >> https://review.openstack.org/#/q/topic:bp/hot-software-config,n,z
> > >> - launch the above template with your created image
> > >>
> > >> cheers
> > >>
> > >> [1] https://review.openstack.org/#/c/58877/7/heat/engine/api.py
> > >> [2] This relies on these not-merged intrinsic functions
> > >> https://review.openstack.org/#/q/topic:bp/cloud-init-resource,n,z
> > >>
> > >> _______________________________________________
> > >> OpenStack-dev mailing list
> > >> OpenStack-dev at lists.openstack.org
> > >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> > >>
> > >>
> > >
> > >
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> > >
> > >
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