Skip to content

Latest commit

 

History

History
73 lines (60 loc) · 3.47 KB

controllers.md

File metadata and controls

73 lines (60 loc) · 3.47 KB
Raw

Controllers

midonet-kube-controllers continuously watches changes in Kubernetes Resources like Pods and Nodes, and makes the necessary changes on the MidoNet API.

The executable contains several controllers. You can choose which controllers to enable by the ENABLED_CONTROLLER environment variable. By default all controllers are enabled.

By design, those controllers are independent each other and can be run in separate processes. Such a setup is not extensively tested though.

midonet-kube-controllers can run anywhere, as far as it has L3 connectivity to the Kubernetes API server. Some of its embedded controllers needs the connectivity to the MidoNet API too. (See the following diagram.)

...................         ...................................
:                 :         :                                 :
:  K8s API server :         :  midonet-kube-controllers       :
:                 :         :                                 :
:                 : Watch   :                                 :
:                 : Annotate:                                 :
:  +-----------+ <-----+    :    +-------------+              :
:  |Node       |  :    |    :    |nodeannotator|              :  Query
:  +-----------+ +--+  +-------> |controller   | +--------------------+
:                 : |       :    +-------------+              :       |
:  +-----------+  : |       :                                 :       |
:  |Pod        | +--+       :                                 :       v
:  +-----------+  : |       :   +--------------------+        :
:                 : |       :   |pod controller      |        :   +-----------+
:  +-----------+  : |       :   +--------------------+        :   |           |
:  |Service    | +--+ Watch :   |node controller     |        :   |MidoNet API|
:  +-----------+  : +---------> +--------------------+ +-+    :   |           |
:                 : |       :   |service controller  |   |    :   +-----------+
:  +-----------+  : |       :   +--------------------+   |    :
:  |Endpoints  | +--+       :   |endpoints controller|   |    :       ^
:  +-----------+  :         :   +--------------------+   |    :       |
:                 :  Update :                            |    :       |
:                 :   +----------------------------------+    :       |
:                 :   |     :                                 :       |
:  +-----------+ <----+     :                                 :       |
:  |Translation|  :         :   +------------------+          :       |
:  +-----------+ +------------> |pusher controller | +----------------+
:                 :  Watch  :   +------------------+          :  Update
:                 :         :                                 :
:                 :         :                                 :
...................         ...................................

pod, node, service, endpoints

These controllers watch the corresponding Kubernetes resources and create/update/delete Translation custom resources accordingly.

pusher

This controller watches Translation custom resources and create/update/delete MidoNet API resources accordingly.

nodeannotator

This controller adds "midonet.org/host-id" annotation to Kubernetes Node resources, by querying MidoNet API with the assumption that MidoNet Host name and Kubernetes Node name on a node match.

This controller also adds "midonet.org/tunnel-zone-id" and "midonet.org/tunnel-endpoint-ip" annotations.

The annotation is used by pod and node controllers.