cloud-network-config-controller

Cloud-network-config-controller [CNCC]

The CNCC is a controller/operator which interfaces with the cloud API endpoints to execute and perform the set up required on behalf of the user creating / updating / deleting the CRs this controller manages. The user in the OpenShift use-case are the network plugins (openshift-sdn / OVN-Kubernetes) which interface with this component using its CRDs. Currently, this is only cloud.network.openshift.io/cloudprivateipconfigs which adds / removes private IP addresses to VM instances associated with Kubernetes nodes.

CloudPrivateIPConfig

A CR for this looks like:

apiVersion: cloud.network.openshift.io/v1
kind: CloudPrivateIPConfig
metadata:
  name: 192.168.126.11
spec:
  node: nodeX
  status:
    node: nodeX
    conditions:
    - message: ""
      reason: ""
      status: "True|False|Unknown"
      type: Assigned

The name of the CR represent the IP address which is to be assigned / removed. Due to a limitation in the Kube API-server, CR names need to be RFC 1123 compliant which means that IPv6 addresses can't just be written as-is. The format this controller thus expects for IPv6 names are a fully expanded IP addresses with colons replaced by dots, ex: fc00:f853:ccd:e793::54 -> fc00.f853.0ccd.e793.0000.0000.0000.0054. Any controller interfacing with this controller for IPv6 assignments must thus be capable of performing a bi-directional conversion to and from that format.

Any assignment of an IP address should only be considered successful when .spec.node == .status.node and .status.conditions[0].status == True, this applies to creation / updates of CRs.

This controller utilizes a finalizer which it sets on any CR which is created. The reason for doing so is to prevent an instance from being removed from the API until this controller has reacted, i.e: making sure that even if a delete is performed while our controller is not running: nothing actually gets deleted and we don't lose out on the event.

The control loop for this controller performs atomic add/deletes. This is to say that for an update there will be two syncs performed and two updates occurring: one removal of the IP address from the current node, upon which the CR is updated, and then a second add to the new node, upon which the CR is updated again.

Credentials

This controller requires credentials to be able to talk to the cloud API. The format for these credentials depend on the cloud and mode of deployment. The controller accepts an argument -secret-name which is to be placed in the namespace this controller is running in. The controller figures out what that namespace is using the environment variable CONTROLLER_NAMESPACE which can be passed to it through the deployment stanza and using the downward-API. The controller will then start watching for secret data change as to get notified of credential rotation, upon which it exits and forces a restart of the pod. The secret also needs to be mounted for this controller to read at start-up, this location is by default: /etc/secret/cloudprovider but can be specified and overridden using the argument -secret-override.

The credentials are expected to look like the following (for vanilla Kubernetes clusters).

GCP

tree /etc/secret/cloudprovider
└── service_account.json

or as a Kubernetes secret defined as:

apiVersion: v1
data:
  service_account.json: 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
kind: Secret
metadata:
  name: cloud-credentials
  namespace: openshift-cloud-network-config-controller
type: Opaque

AWS

Secret

tree /etc/secret/cloudprovider
├── aws_access_key_id 
└── aws_secret_access_key

or as a Kubernetes secret defined as:

apiVersion: v1
data:
  aws_access_key_id: QUtJQVdXT1NCDIAaiaNVhGREJRRVA0N04=
  aws_secret_access_key: MG0rV05WMASOKSo2VCdmR1RG9mV1pIcDh4bWJDinsaSSAbXWEx1bHQzekhJU2Jud1UyMw==
kind: Secret
metadata:
  name: cloud-credentials
  namespace: openshift-cloud-network-config-controller
type: Opaque

ConfigMap

If -platform-aws-ca-override=<file name> is set then the CNCC expects to find a valid CA certificate chain at that location. This CA certificate chain will be used when talking to the AWS API. The Cluster Network Operator will create a ConfigMap named kube-cloud-config inside the CNCC's namespace and will mount this ConfigMap at location /kube-cloud-config. It will then set -platform-aws-ca-override=/kube-cloud-config/ca-bundle.pem. Additionally, if parameter -config-name=<name of ConfigMap> is set then the CNCC will start monitoring that ConfigMap for update or delete operations. If such an event gets triggered, the process will gracefully shutdown. Kubernetes will subsequently restart the container, thus spawning a process with updated configuration. The default value for -config-name is kube-cloud-config.

tree /kube-cloud-config
└── ca-bundle.pem

Or as a Kubernetes ConfigMap defined as:

apiVersion: v1
data:
  ca-bundle.pem: <data>
kind: ConfigMap
metadata:
  name: kube-cloud-config
  namespace: openshift-cloud-network-config-controller

Azure

tree /etc/secret/cloudprovider
├── azure_client_id 
├── azure_client_secret 
├── azure_region 
├── azure_resource_prefix 
├── azure_resourcegroup 
├── azure_subscription_id 
└── azure_tenant_id

or as a Kubernetes secret defined as:

apiVersion: v1
data:
  azure_client_id: NGYwM2JjYWItN2I2My00SSoaNjE3LTk2NDEtMGUyZWViOWNjNWVi
  azure_client_secret: aEs3TVUzMaiajiDD2tfXy0uVGNYaDU1LVpOcm5FMHMtUndpskD4ueFBvQg==
  azure_region: ZWFzdHVz
  azure_resource_prefix: Y2ktbG4tNnNqMzMydCs0xZDA5ZC1kZHE2Mg==
  azure_resourcegroup: Y2ktbG4tNnNqMzMydC0xZDA5ZC1kZHE2Mi1yZw==
  azure_subscription_id: ZDM4ZjFlMzgsokPSAAHUDH
  azure_tenant_id: NjA0DSJAaN2M3ZTktYjJhZsokAOKADH
kind: Secret
metadata:
  name: cloud-credentials
  namespace: openshift-cloud-network-config-controller
type: Opaque

OpenStack

Secret

tree /etc/secret/cloudprovider
└── cloud.yaml

or as a Kubernetes secret defined as:

apiVersion: v1
data:
  clouds.yaml: <base64 string>
kind: Secret
metadata:
  name: cloud-credentials
  namespace: cloud-network-config-controller
type: Opaque

ConfigMap

The Cluster Network Operator will create a ConfigMap named kube-cloud-config inside the CNCC's namespace and will mount this ConfigMap at location /kube-cloud-config. The CNCC will look for a file at location /kube-cloud-config/ca-bundle.pem. If the content of that file is != "", then the operator will assume that this is a valid CA chain and will use this data when talking to the OpenStack API. If parameter -config-name=<name of ConfigMap> is set to anything other than "", then the CNCC will start monitoring that ConfigMap for update or delete operations. If such an event gets triggered, the process will gracefully shutdown. Kubernetes will subsequently restart the container, thus spawning a process with updated configuration. The default value for -config-name is kube-cloud-config.

tree /kube-cloud-config
└── ca-bundle.pem

Or as a Kubernetes ConfigMap defined as:

apiVersion: v1
data:
  ca-bundle.pem: <data>
kind: ConfigMap
metadata:
  name: kube-cloud-config
  namespace: openshift-cloud-network-config-controller

Attributes affecting assignments - subnets / capacity / NICs

Assigning private IP addresses to instances on the cloud comes with some limitations.

Subnets

An IP address can only be assigned to subnets which can host it. In the cloud subnets vary depending on the availability zone an instances is located in. This controller thus also retrieves the subnet information from the cloud API and annotates the node object with it, see below for what this annotation looks like.

Capacity

Clouds limit the amount of private IP addresses which can be associated with instances. Some have a variable capacity per instance type and IP family (AWS) others have a global and fixed capacity defined (GCP/Azure). This controller does not validate that if capacity is superseded or not, it is up to the client controller to initialize its state and track how many assignments are still possible.

NICs

Any CloudPrivateIPConfig currently is only added to the instances' first NIC in the order specified by the cloud. On Azure the notion of a "primary" instance exists, and is hence used, even if that NIC might not be defined first. As to account for future work where IP addresses might be assigned to other NICs besides the first one, the annotation reports an array of interface/subnet/capacity. For now this array is always of length 1, with the first/"primary" interface.

All of these attributes are placed on the node object as an annotation, which looks like:

cloud.network.openshift.io/egress-ipconfig: [{"interface": "$IFNAME/$IFID", "ifaddr": {"ipv4": "$IPv4_ADDRESS/$IPv4_SUBNET_MASK", "ipv6": "$IPv6_ADDRESS/$IPv6_SUBNET_MASK"}, "capacity": {"ip": "$IPv4_AND_IPv6_CAPACITY"}}]

if the capacity is IP family agnostic. If that is not the case, the annotation will look like:

cloud.network.openshift.io/egress-ipconfig: [{"interface": "$IFNAME/$IFID", "ifaddr": {"ipv4": "$IPv4_ADDRESS/$IPv4_SUBNET_MASK", "ipv6": "$IPv6_ADDRESS/$IPv6_SUBNET_MASK"}, "capacity": {"ipv4": "$IPv4_CAPACITY", "ipv6": "$IPv6_CAPACITY"}}]

How to hack/debug

When you want to debug this component, use one of the following methods.

Run locally

If you want to run the operator directly on your computer, you can run the ./hack/run-locally.sh, but make sure you have a KUBECONFIG initialized in your environment variables. If running against an OpenShift cluster: the credentials will be copied locally to your computer. That being said, you probably won't be able to talk to the cloud API endpoints from your local development environment, so you might need to comment out code which is non-essential to your testing.

Patch the operator to run from a new image

If you have issues talking directly to the cloud API endpoints or if you want to test how the operator runs inside the actual container, use this method.

Set up your own publicly accessible repository. For example, use a quay repository:

export CNCC_REPOSITORY="quay.io/akaris/cloud-network-config-controller"

If you prefer using docker instead of podman, run:

export CONTAINER_ENGINE="docker"

Run:

hack/run_in_cloud.sh

This will then build the container from the Dockerfile, tag the image as ${CNCC_REPOSITORY}:${UUID} where ${UUID} is a unique ID, push the image to the registry and patch the clusterversion operator and the network-operator so that this new image will be used.

In order to rollback, run oc edit clusterversion version and remove the configuration in /spec/overrides. The clusterversion operator should then bring the cluster back to its original state.

Note: If the cloud-network-config-controller pod runs into authentication problems after using this method, it may be necessary to delete the pod manually to "kick" it.