On 01/08/2014 06:57 PM, Prasad Vellanki wrote:
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
Prasad,
Just to clarify, you want Heat to facilitate bootstrapping a black box
(third-party virtual appliance) that has no consistent bootstrapping
interface (such as cloud-init)? The solution you propose I think goes
along the lines of having Heat notify an out-of-vm bootstrapping system
(such as SSH) to connect to the black box and execute the bootstrapping.
If so, I see a problem with this approach:
Heat requires the running of commands inside the virtual machine to know
when the virtual machine is done bootstrapping, for whatever definition
of bootstrapping you use (OS booted, vs OS loaded and ready to provide
service).
This could be handled by modifying the init scripts to signal the end of
booting, but one constraint you mentioned was that images may not be
modified.
Another approach that could be used today is to constantly connect to
the SSH port of the VM until you receive a connection. The problem with
this approach is who loads the ssh keys into the image? SSH key
injection is currently handled by the bootstrapping process. This is a
chicken-egg problem and a fundamental reason why bootstrapping should be
done internally to the virtual machine driven by Heat. Assuming this
model were used, a notification that the booting process has completed
is only an optimization to indicate when SSH harassment should begin :)
One possible workaround, mentioned in your use case is that the virtual
appliance contacts a REST server (to obtain bootstrapping information,
including possibly SSH keys). Since I assume these virtual appliances
come from different vendors, this would result in REST bootstrapping
server proliferation which is bad for operators as each server has to be
secure-ified, scale-ified, HA-ifed, and documented.
The path of least resistance in this case seems to be to influence the
appliance vendors to adopt cloud-init rather then do unnatural acts
inside infrastructure to support appliance vendors who are unwilling to
conform to Open Source choices made by a broad community of technology
experts (in this case, I mean not just the OpenStack community, but
rather nearly every cloud vendor has made cloudinit central to their
solutions). Since the appliance vendors will add cloud-init to their
image sooner or later due to operator / customer pressure, it is also
the right choice today.
It is as simple as adding one package to the built image. In exchange,
from a bootstrapping perspective, their customers get a simple secure
reliable scalable highly available experience on OpenStack and likely
other IAAS platforms.
Regards
-steve
On Tue, Jan 7, 2014 at 11:40 AM, Clint Byrum <cl...@fewbar.com
<mailto:cl...@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 <sba...@redhat.com
<mailto:sba...@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
<sba...@redhat.com <mailto:sba...@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
> >>
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> >>
> >
> >
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