Proposed Service Architecture for Kosmos

Also including the old massive overview .dot file,
its not referenced, but it might be handy in the future.

Change-Id: I68dc4521afe4efb520748fbc323867a045a2eb77

doc/source/conf.py

@@ -26,6 +26,9 @@ extensions = [
     #'sphinx.ext.intersphinx',
     'oslosphinx',
     'yasfb',
+    'sphinx.ext.graphviz',
+    'sphinxcontrib.seqdiag',
+    'sphinxcontrib.httpdomain',
 ]
 
 # Feed configuration for yasfb

doc/source/index.rst

@@ -14,6 +14,14 @@ Liberty approved specs:
 
    specs/liberty/*
 
+Mitaka approved specs:
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   specs/mitaka/*
+
 
 kosmos-specs Repository Information
 ===================================================

requirements.txt

@@ -2,3 +2,5 @@ pbr>=0.11,<2.0
 oslosphinx
 sphinx>=1.1.2,!=1.2.0,!=1.3b1,<1.3
 yasfb>=0.5.1
+sphinxcontrib-seqdiag
+sphinxcontrib-httpdomain

specs/mitaka/sysarch.rst

@@ -0,0 +1,133 @@
+..
+
+This work is licensed under a Creative Commons Attribution 3.0 Unported License.
+http://creativecommons.org/licenses/by/3.0/legalcode
+
+..
+  This template should be in ReSTructured text. The filename in the git
+  repository should match the launchpad URL, for example a URL of
+  https://blueprints.launchpad.net/kosmos/+spec/awesome-thing should be named
+  awesome-thing.rst .  Please do not delete any of the sections in this
+  template.  If you have nothing to say for a whole section, just write: None
+  For help with syntax, see http://sphinx-doc.org/rest.html
+  To test out your formatting, see http://www.tele3.cz/jbar/rest/rest.html
+
+=====================
+ System Architecture
+=====================
+
+Overview
+========
+
+The system should be made up of a few services, that are small, and horizontally scalable.
+
+The system should be the following:
+- Scalable
+- Fault Tolerant
+- Use other OpenStack projects as first class citizens
+    - For the GSLB appliance drivers the default should be `Designate`_
+    - For regional pool members Neutron `LBaaS V2`_ should be the default
+
+.. note:: This is for the MVP. Post MVP we need to also be able to run as a global service.
+
+
+Overview Diagram
+----------------
+
+.. graphviz:: sysarch/sysarch-diagram-overview.dot
+
+
+Services
+--------
+
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+| service name          | deployment model                                | purpose                                                                       | notes                                                                                             |
++=======================+=================================================+===============================================================================+===================================================================================================+
+| kosmos-api            | multiple                                        | Configuration of GSLBs                                                        |                                                                                                   |
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+| kosmos-conductor      | multiple - single region                        | Database Access                                                               |                                                                                                   |
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+| kosmos-status-checker | multiple - global                               | Check status of endpoints                                                     |                                                                                                   |
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+| kosmos-engine         | multiple - single region                        | Business Logic                                                                |                                                                                                   |
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+| GSLB Appliance        | multiple - global (depending on appliance used) | Applicance that is used by Kosmos to direct traffic to the correct endpoints. | This is Designate in the reference Implementation                                                 |
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+| Endpoints             | multiple - multiple regions                     | The destination for the traffic that is being load balanced by Kosmos         | This will be LBaaS V2 Load Balancers by default, but could also be IPs or Hardware Load Balancers |
++-----------------------+-------------------------------------------------+-------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------+
+
+kosmos-api
+^^^^^^^^^^
+
+The API would be a WSGI service that implements the API Spec previously approved.
+
+It should follow the standard OpenStack patterns (use Keystone / oslo.middleware / oslo.context)
+
+kosmos-conductor
+^^^^^^^^^^^^^^^^
+
+This will act as a single point of access to the DB, allowing for consistent data validation.
+
+As results are fed in from status-checkers, then engine will decide if an endpoint is suitable to be included in the pool. As it adds and removes nodes, it will
+update both the database, and the GSLB appliance, via the plugin. (e.g. if using the Designate plugin it would remove the endpoint's IP from the record)
+
+.. warning:: The logging component described below may be cut in the MVP
+
+There is a logging component that could be a separate DB, a timeseries DB, a columnar DB, elastic search or other storage system
+This will store a section of history for the pools, to allow users to see when / why endpoints were added / removed from the load balancer.
+
+.. graphviz:: sysarch/sysarch-diagram-conductor.dot
+
+kosmos-status-checker
+^^^^^^^^^^^^^^^^^^^^^
+
+This is a worker style service that will run status checks on the defined endpoints.
+
+This will have a plugin interface to allow for more checks to the loaded by different plugins, or for custom checks to be written by the deployer (using standard OpenStack plugin patterns)
+
+For example, any pool-members / endpoints that are LBaaS instances will not call into the VIP, but will call the LBaaS V2 API to get the health of the regional members.
+
+.. graphviz:: sysarch/sysarch-diagram-status-checker.dot
+
+kosmos-engine
+^^^^^^^^^^^^^
+
+This is where all the business logic resides. This service will consume status results and decide if an endpoint should be removed / added.
+This service will then use the plugin loaded for the GSLB backend to orchestrate this.
+
+The plugins will allow different types of GSLB appliances / services to be used, and will use standard OpenStack plugin patterns.
+
+.. graphviz:: sysarch/sysarch-diagram-engine.dot
+
+
+Entity Relationship Diagram
+---------------------------
+
+.. graphviz:: sysarch/erd-diagram.dot
+
+
+Example
+-------
+
+This is an example flow of information, when we are using Designate and checking the health info of a Neutron LBaaS load balancer.
+The plugin components are excluded for clarity, but would be between the "Status Check" and "Engine" components.
+
+.. seqdiag:: sysarch/example-flow.diag
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  kosmos-drivers
+
+Milestones
+----------
+
+Target Milestone for completion:
+  M-2
+
+.. _Designate: http://wiki.openstack.org/wiki/Designate
+.. _LBaaS V2: http://https://wiki.openstack.org/wiki/Neutron/LBaaS

specs/mitaka/sysarch/erd-diagram.dot

@@ -0,0 +1,91 @@
+digraph "models_diagram" {
+    graph[overlap=false, splines=true, fontname="sans-serif", fontsize=10 ]
+    node [ fontname="sans-serif"fontsize=10 ];
+    edge [ fontname="sans-serif"fontsize=10 ];
+
+
+    "LB" [shape=record, label="{\
+      loadbalancers|
+      id :uuid\l\
+      project_id :string\l\
+      domain_id :string\l\
+      name :string\l\
+      description :string\l\
+      fqdn :string\l\
+      zone_name :string\l\
+      flavor :enum\l\
+      appliance_id :string\l\
+      pool_ids :uuid\l\
+    }"]
+
+    "Pools" [shape=record, label="{\
+      pools|\l\
+      id :uuid\l\
+      project_id :string\l\
+      domain_id :string\l\
+      name :string\l\
+      description :string\l\
+    }"]
+
+    "PoolMembers" [shape=record, label="{\
+      pool_members|\l\
+      id :uuid\l\
+      project_id :string\l\
+      domain_id :string\l\
+      pool_id :string\l\
+      name :string\l\
+      description :string\l\
+      type :enum\l\
+    }"]
+
+    "PoolMemberParameters" [shape=record, label="{\
+      pool_member_parameters|\l\
+      id :uuid\l\
+      project_id :string\l\
+      domain_id :string\l\
+      pool_member_id :string\l\
+      key :enum\l\
+      value :string\l\
+    }"]
+
+    "Monitors" [shape=record, label="{\
+      monitors|\l\
+      id :uuid\l\
+      project_id :string\l\
+      domain_id :string\l\
+      name :string\l\
+      description :string\l\
+      type :string\l\
+      target :string\l\
+      auth :bool\l\
+    }"]
+
+    "MonitorParameters" [shape=record, label="{\
+      monitor_parameters|\l\
+      id :uuid\l\
+      project_id :string\l\
+      domain_id :string\l\
+      monitor_id :uuid\l\
+      key :enum\l\
+      value :string\l\
+    }"]
+
+    "PoolsMonitor" [shape=record, label="{\
+      pools_monitors|\l\
+      pool_id :uuid\l\
+      monitor_id :uuid\l\
+    }"]
+
+
+    { rank=same; "LB", "Pools" }
+    { rank=same; "PoolsMonitor" "PoolMembers" }
+    { rank=same; "Monitors" "PoolMemberParameters" "MonitorParameters" }
+
+    "LB" -> "Pools" [arrowtail=odot, arrowhead=crow, dir=both]
+
+    "Pools" -> "PoolsMonitor" [arrowtail=odot, arrowhead=crow, dir=both]
+    "PoolsMonitor" -> "Monitors" [arrowtail=crow, arrowhead=odot, dir=both]
+    "Monitors" -> "MonitorParameters" [arrowtail=odot, arrowhead=crow, dir=both]
+    "Pools" -> "PoolMembers" [arrowtail=odot, arrowhead=crow, dir=both]
+    "PoolMembers" -> "PoolMemberParameters" [arrowtail=odot, arrowhead=crow, dir=both]
+}

specs/mitaka/sysarch/example-flow.diag

@@ -0,0 +1,19 @@
+seqdiag {
+
+    "End User";
+    Engine ->       Conductor                                                       [label = "Get Load Balancer Information"];
+    Engine <--      Conductor;
+
+    Engine ->       "Status Check"                                                  [label = "Tell Status Check to do a healthcheck"];
+                    "Status Check" ->   "Neutron LBaaS API"                         [label = "Get the Regional information from LBaaS V2 Status API"];
+                    "Status Check" <--  "Neutron LBaaS API";
+    "Engine" <--    "Status Check";
+
+    Engine ->       "Designate API"                                                 [label = "Tell Designate about what IPs to send traffic to"]
+                    "Designate API" -> "DNS Servers"                                [label = "Designate updates DNS Server"]
+                    "Designate API" <--"DNS Servers"
+    Engine <--      "Designate API"
+
+    "End User" ->   "DNS Servers"                                                   [label = "User asks for IPs of Service"]
+    "End User" <--  "DNS Servers"                                                   [label = "DNS Returns IPs for the LBaaS VIPs of currently available regions"]
+}

specs/mitaka/sysarch/sysarch-diagram-conductor.dot

@@ -0,0 +1,34 @@
+digraph "Kosmos"{
+    rankdir=TB
+    node [ fontname="sans-serif"fontsize=10 ];
+    edge [ fontname="sans-serif"fontsize=10 ];
+    label="kosmos-conductor";
+    overlap="ortho";
+    fontname="sans-serif"
+    newrank=true
+
+    subgraph cluster_conductor_service {
+        fontname="sans-serif"
+        label="kosmos-conductor";
+        fontsize=12
+
+        Conductor[label="Conductor"];
+        Database[label="Database", shape="folder"];
+        Logger[label="Logger", shape="folder"];
+    }
+
+    { rank=same; "Conductor" "Engine" "WSGI" }
+
+    WSGI [style="invisible"]
+    Engine [style="invisible"]
+
+    WSGI -> Conductor [label="kosmos-api"];
+
+    Conductor -> Database [dir="both"];
+    Conductor -> Logger [dir="both"];
+
+    Conductor -> Engine [label="kosmos-engine"];
+
+
+
+}

specs/mitaka/sysarch/sysarch-diagram-engine.dot

@@ -0,0 +1,34 @@
+digraph "Kosmos"{
+    rankdir=TB
+    node [ fontname="sans-serif"fontsize=10 ];
+    edge [ fontname="sans-serif"fontsize=10 ];
+    label="kosmos-engine";
+    overlap="ortho";
+    fontname="sans-serif"
+    newrank=true
+
+    Conductor [style="invisible"]
+
+    subgraph cluster_engine_service {
+        fontname="sans-serif"
+        label="kosmos-engine";
+        fontsize=12
+
+        node[shape=record];
+        Engine[label="<f0> Engine|<f1> GSLB Plugin Interface |<f2> Status Check Consumer"];
+        PluginDriver[label="GSLB Plugin Driver", shape="component"]
+    }
+
+
+    ApplicanceAPI [style="invisible"]
+    Worker [style="invisible"]
+
+    Engine:f0 -> Conductor [label="kosmos-conductor"];
+
+    Engine:f1 -> PluginDriver [dir="both"];
+    PluginDriver -> ApplicanceAPI [dir="both" label="GSLB Appliance API"];
+
+
+    Worker -> Engine:f2[label="kosmos-status-checker"];
+
+}

specs/mitaka/sysarch/sysarch-diagram-overview.dot

@@ -0,0 +1,67 @@
+digraph "Kosmos"{
+    node [ fontname="sans-serif"fontsize=10; shape=record ];
+    edge [ fontname="sans-serif"fontsize=10 ];
+    label="Kosmos System Overview";
+    overlap="ortho";
+    fontname="sans-serif"
+    newrank=true
+
+
+    API_user [
+        label="API User"
+        style="dashed"
+    ]
+
+    cluster_keystone [
+        label="Keystone";
+        style="dashed"
+    ]
+
+    cluster_api_service [
+        label="kosmos-api";
+    ]
+
+    cluster_conductor_service [
+        label="kosmos-conductor";
+    ]
+
+    cluster_engine_service [
+        label="kosmos-engine";
+    ]
+
+    cluster_gslb_appliance [
+        label="GSLB Appliance";
+        style="dotted"
+    ]
+
+    cluster_status_checks [
+        label="kosmos-status-check";
+    ]
+
+    cluster_endpoints [
+        label="Endpoints";
+        style="dashed"
+    ]
+
+    end_user [
+        label="End User"
+        style="dashed"
+    ]
+
+    API_user -> cluster_api_service
+    cluster_api_service -> cluster_keystone
+    cluster_api_service -> cluster_conductor_service
+
+    { rank=same; "API_user" "cluster_api_service" "cluster_keystone" }
+
+    cluster_conductor_service -> cluster_engine_service
+    cluster_status_checks -> cluster_engine_service
+    cluster_status_checks -> cluster_endpoints
+    cluster_engine_service -> cluster_gslb_appliance
+
+    { rank=same; "cluster_engine_service" "cluster_gslb_appliance" "end_user"}
+    { rank=same; "cluster_endpoints"}
+    end_user -> cluster_gslb_appliance
+    end_user -> cluster_endpoints
+
+}

specs/mitaka/sysarch/sysarch-diagram-status-checker.dot

@@ -0,0 +1,35 @@
+digraph "Kosmos"{
+    rankdir=TB
+    node [ fontname="sans-serif"fontsize=10 ];
+    edge [ fontname="sans-serif"fontsize=10 ];
+    label="kosmos-status-checker";
+    overlap="ortho";
+    fontname="sans-serif"
+    newrank=true
+
+    subgraph cluster_status_checks {
+        fontname="sans-serif"
+        fontsize=12
+        label="kosmos-status-checker";
+
+        Worker[label="Status Checking Worker"];
+
+        node[shape=record];
+        Checks[label="<f0> Build In Checks Interface |<f1> GSLB Plugin Checks Interface"];
+
+        BuiltInChecks[label="Built In Status Checks"]
+        PluginChecks[label="Plugin Status Checks", shape="component"]
+    }
+
+    Endpoints [style="invisible"]
+    Engine [style="invisible"]
+
+    Worker -> Engine [label="kosmos-engine"];
+    Worker -> Checks [dir="both"];
+    Checks:f0 -> BuiltInChecks [dir="both"];
+    Checks:f1 -> PluginChecks [dir="both"];
+    BuiltInChecks -> Endpoints [dir="both" label="Endpoints"];
+    PluginChecks -> Endpoints [dir="both" label="Endpoints"];
+
+
+}

specs/mitaka/sysarch/sysarch-diagram.dot

@@ -0,0 +1,114 @@
+digraph "Kosmos"{
+    rankdir=TB
+    node [ fontname="sans-serif"fontsize=10 ];
+    edge [ fontname="sans-serif"fontsize=10 ];
+    label="Kosmos System Overview";
+    overlap="ortho";
+    fontname="sans-serif"
+    newrank=true
+
+    subgraph cluster_keystone {
+        fontname="sans-serif"
+        label="Keystone";
+        fontsize=12
+        style="dashed"
+
+        Keystone[label="Keystone API", style="dotted"];
+    }
+
+    subgraph cluster_api_service {
+        fontname="sans-serif"
+        label="API Service";
+        fontsize=12
+
+        WSGI[label="WSGI API"];
+    }
+
+
+    subgraph cluster_conductor_service {
+        fontname="sans-serif"
+        label="Conductor Service";
+        fontsize=12
+
+        Conductor[label="Conductor"];
+        Database[label="Database", shape="folder"];
+        Logger[label="Logger", shape="folder"];
+    }
+
+    subgraph cluster_engine_service {
+        fontname="sans-serif"
+        label="Engine Service";
+        fontsize=12
+
+        node[shape=record];
+        Engine[label="<f0> Engine|<f1> GSLB Plugin Interface |<f2> Status Check Consumer"];
+        PluginDriver[label="GSLB Plugin Driver", shape="component"]
+    }
+
+    subgraph cluster_gslb_appliance {
+        fontname="sans-serif"
+        fontsize=12
+        label="GSLB Appliance";
+        style="dashed"
+
+        Applicance[label="GSLB Traffic Director", style="dotted"];
+        ApplicanceAPI[label="GSLB Appliance API", style="dotted"];
+    }
+
+    subgraph cluster_status_checks {
+        fontname="sans-serif"
+        fontsize=12
+        label="Status Check Service";
+
+        Worker[label="Status Checking Worker"];
+
+        node[shape=record];
+        Checks[label="<f0> Build In Checks Interface |<f1> GSLB Plugin Checks Interface"];
+
+        BuiltInChecks[label="Built In Status Checks"]
+        PluginChecks[label="Plugin Status Checks", shape="component"]
+    }
+
+    subgraph cluster_endpoints {
+        fontname="sans-serif"
+        fontsize=12
+        label="Endpoints";
+        style="dashed"
+
+        Endpoint1[label="Endpoint", style="dotted"];
+        Endpoint2[label="Endpoint", style="dotted"];
+        Endpoint3[label="Endpoint", style="dotted"];
+        LBaaSAPI[label="LBaaS Status API", style="dotted"];
+
+    }
+
+    AdminUser[label="GSLB User", style="dashed"];
+    AdminUser -> WSGI [dir="both"];
+
+    Keystone -> WSGI [dir="both"];
+
+    WSGI -> Conductor:f0 [dir="both"];
+
+    Conductor -> Database [dir="both"];
+
+    Engine:f0 -> Conductor [dir="both"];
+
+    Engine:f1 -> PluginDriver [dir="both"];
+    PluginDriver -> ApplicanceAPI [dir="both"];
+
+    Applicance -> ApplicanceAPI [dir="both"];
+
+    Worker -> Engine:f2;
+    Worker -> Checks [dir="both"];
+    Checks:f0 -> BuiltInChecks [dir="both"];
+    Checks:f1 -> PluginChecks [dir="both"];
+    BuiltInChecks -> {Endpoint1; Endpoint2; Endpoint3; LBaaSAPI} [dir="both"];
+    LBaaSAPI -> {Endpoint1; Endpoint2; Endpoint3}
+    PluginChecks -> {Endpoint1; Endpoint2; Endpoint3} [dir="both"];
+
+    EndUser[label="End User", style="dashed"];
+
+    EndUser -> Applicance
+    EndUser -> {Endpoint1; Endpoint2; Endpoint3}
+
+}