Helm Reference

Helm is the package manager for Kubernetes. It lets you define, install, and upgrade Kubernetes base applications. For more information about Helm, please the visit official website: https://helm.sh.

For information on how to install helm please refer to Installing Helm.

CORD Helm Charts

All helm charts used to install CORD can be found in the helm-chart repository. Most of the top-level directories in that repository (e.g., onos, voltha, xos-core) correspond to components of CORD that can be installed independently. For example, it is possible to bring up onos without voltha, and vice versa. You can also bring up XOS by itself (xos-core) or XOS with its GUI (xos-core and xos-gui). This can be useful if you want to work on just the CORD data models, without any backend components.

The xos-services and xos-profiles directories contain helm charts for individual services and profiles (a mesh of services), respectively. While it is possible to use Helm to bring up an individual service, collections of related services are typically installed as a unit; we call this unit a profile. Looking in the xos-profiles directory, rcord-lite is an example profile. It corresponds to R-CORD, and inspecting its requirements.yaml file shows that it, in turn, depends on the volt and vrouter services, among several others.

Some of the profiles bring up sub-systems that other profiles then build upon. For example, base-openstack brings up three platform related services (onos-service, openstack, and vtn-service), which effectively provisions CORD to support OpenStack-based VNFs. Once the services in the base-openstack profile are running, it is then possible to bring up the mcord profile, which corresponds to ~10 other services. It is also possible to bring up an individual service by executing its helm chart; for example xos-services/simpleexampleservice.

Note: Sometimes we install Individual services by first "wrapping" them in a profile. For example, SimpleExampleService is deployed from the xos-profiles/demo-simpleexampleservice profile, rather than directly from xos-services/simpleexampleservice. The latter is included by reference from the former. This is not a fundamental limitation, but we do it when we want to run the tosca-loader that loads a TOSCA workflow into CORD. This feature is currently available at only the profile level.

Similarly, the base-kubernetes profile brings up Kubernetes in support of container-based VNFs. This corresponds to the kubernetes-service, not to be confused with CORD's use of Kubernetes to deploy the CORD control plane. Once this profile is running, it is possible to bring up an example VNF in a container by executing its helm chart; for example xos-profiles/demo-simpleexampleservice.

Note: The base-kubernetes configuration does not yet incorporate VTN. Doing so is work-in-progress.

Finally, note that the templates sub-directory in both the xos-services and xos-profiles directories includes one or more TOSCA-related files. These play a role in configuring the service graph and provisioning the individual services contained in that service graph. This happens once the helm charts have done their job, and is technically a post-install operation, as discussed in the Operations Guide.

Download the helm-charts Repository

You can get the CORD helm charts by cloning the helm-charts repository:

git clone https://gerrit.opencord.org/helm-charts

Note: If you have downloaded the CORD code following the Getting the Source Code guide, you'll find it in ~/cord/helm-charts.

IMPORTANT: All the helm commands needs to be executed from within this directory

Add the CORD Repository to Helm

If you don't want to download the repository, you can make the charts available to helm by adding the repo to the list of repos it can obtain charts from:

helm repo add cord https://charts.opencord.org/master
helm repo update

If you decide to follow this route, you have to use the repo name (in this case cord) with a prefix ( cord/) to specify which repo to obtain a chart from.

For example:

helm install -n xos-core xos-core

would become:

helm install -n xos-core cord/xos-core

Overriding chart values

Occasionally you may need to override and customize the default settings of a chart.

This is done using a "values file", and is done most frequently during development or when customizing a deployment.

Development-specific and deployment example values files can be found in the helm-charts/examples directory.

Specifying a Docker registry

Most charts specify a global value for the address of a Docker image registry. By default this is blank, assuming that images will be pulled from the global hub.docker.com registry:

global:
  registry: ''

This would be overridden as follows - make sure to include the trailing / character to separate the registry from the name of the container:

global:
  registry: '10.90.0.101:30500/'

Note that using setting this value with change the registry setting for every image in a chart.

To handle building and pushing images to a registry, see the development documentation.

If you want to change only the registry for one specific image, the easiest way is to modify the repository setting - for example:

images:
  xos_gui:
    repository: 'xosproject/xos-gui'
    tag: '2.1.0'
    pullPolicy: 'Always'

  xos_ws:
    repository: 'xosproject/xos-ws'
    tag: '2.0.0'
    pullPolicy: 'Always'

global:
  registry: ''

You would modify the repository value for the specific image, but not the global registry value:

images:
  xos_gui:
    repository: '10.90.0.101:30500/xosproject/xos-gui'
    tag: '2.1.0'
    pullPolicy: 'Always'

  xos_ws:
    repository: 'xosproject/xos-ws'
    tag: '2.0.0'
    pullPolicy: 'Always'

global:
  registry: ''