Element overcloud-agent replaces os-collect-config

The element overcloud-agent is a purely package driven replacement for
the tripleo-image-elements element os-collect-config.

All it does is install the python-heat-agent package and enable the
os-collect-config service.

The intention is for this element to be merged unused, then a change
to the tripleo-common/image-yaml will confirm that it is working as
expected.

This is part of the effort to deprecate the entire
tripleo-image-elements repo.

Change-Id: I1f3bb386660f36813515544dc73b1c5e08467553

elements/overcloud-agent/README.md

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+Install python-heat-agent and enable os-collect-config to run as a system
+service. By default it will run os-refresh-config on any changes.
+
+Configuration
+-------------
+
+Heat Metadata can be used to configure os-collect-config:
+
+    os-collect-config:
+      command: os-refresh-config
+      cachedir: /var/run/os-collect-config
+      collectors:
+        - heat_local
+        - ec2
+        - cfn
+      polling_interval: 300
+      cfn:
+        metadata_url: http://foo:8000/v1
+        heat_metadata_hint: /var/lib/heat-cfntools/cfn-metadata-server
+        stack_name: required-stack-name
+        access_key_id: abcdefghijklmnop091234
+        secret_access_key: fffeeeeddddccccaaaa99999
+        path: ThisResource.Metadata
+        ca_certificate: /etc/ssl/ca.crt
+      ec2:
+        metadata_url: http://169.254.169.254/latest/meta-data
+      heat_local:
+        path: /var/lib/heat-cfntools/cfn-init-data
+
+Note that `metadata_url` is optional, as it should be determined by the
+file `heat_metadata_hint` refers to. This file is injected by Heat via
+cloud-init at first boot. Those two parameters are the only optional
+parameters. All of the others are required for the cfn data source
+to function. Note that `ca_certificate` is also optional but required
+in many cases where the metadata api is behind ssl.
+
+`ec2` and `heat_local` do not require any configuration to work.
+
+Typically the cfn collector is configured via EC2 metadata in a Heat
+template:
+
+    Resources:
+      myserver:
+        Type: OS::Nova::Server
+        Properties:
+          ...
+        Metadata:
+          os-collect-config:
+            cfn:
+              access_key_id:
+                Ref: Key
+              path: MyServerConfig.Metadata
+              secret_access_key:
+                Fn::GetAtt:
+                - Key
+                - SecretAccessKey
+              stack_name:
+                Ref: AWS::StackName
+              ca_certificate: /etc/ssl/ca.crt
+
+The EC2 collector takes this metadata, passes it to os-apply-config
+which in turn writes it out to /etc/os-collect-config.conf.
+
+Note that the configuration references some other resources - a key
+and access key, which are declared using:
+
+    Resources:
+      Key:
+        Properties:
+          UserName:
+            Ref: User
+        Type: AWS::IAM::AccessKey
+      User:
+        Properties:
+          Policies:
+          - Ref: AccessPolicy
+        Type: AWS::IAM::User
+
+Note also that the IAM::User references an access policy which should
+look like:
+
+    Resources:
+      AccessPolicy:
+        Properties:
+          AllowedResources:
+          - MyServerConfig
+        Type: OS::Heat::AccessPolicy
+
+and, finally, the crucial bit is the MyServerConfig policy which is
+referenced in the cfn collector configuration and the access policy:
+
+    Resources:
+      MyServerConfig:
+        Metadata:
+          os-collect-config:
+            cfn:
+              access_key_id:
+                Ref: Key
+              path: MyServerConfig.Metadata
+              secret_access_key:
+                Fn::GetAtt:
+                - Key
+                - SecretAccessKey
+              stack_name:
+                Ref: AWS::StackName
+          nova:
+            ...
+          keystone:
+            ...
+        Properties:
+          ImageId: '0'
+          InstanceType: foo
+        Type: AWS::AutoScaling::LaunchConfiguration
+
+Essentially, this AutoScaling::LaunchConfiguration resource is a bunch
+of boilerplate gunk to provide a metadata container from where the
+os-collect-config cfn collector can pull configuration which will be
+applied by os-apply-config. There's a os-collect-config section to
+ensure the configuration from the EC2 metadata doesn't get
+overwritten. And the rest is dummy values for the
+LaunchConfiguration's required properties.
+

elements/overcloud-agent/element-deps

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+package-installs

elements/overcloud-agent/install.d/10-enable-os-collect-config

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+#!/bin/bash
+set -eux
+
+systemctl enable os-collect-config

elements/overcloud-agent/package-installs.yaml

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+os-collect-config:
+python-heat-agent:

elements/overcloud-agent/pkg-map

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+{
+  "family": {
+    "debian": {
+      "os-collect-config": "python-os-collect-config"
+    }
+  },
+  "default": {
+    "os-collect-config": "os-collect-config"
+  }
+}