CORD uses Helm to manage the lifecycles of its component micro-services. This page describes how to perform some basic tasks using Helm commands. It assumes that charts are being installed from CORD's online Helm chart repository. To add this repository to your local Helm installation:
helm repo add cord https://charts.opencord.org helm repo update
If you have checked out the helm-charts repository locally and are installing charts from that, replace cord/ in the examples below with the path to the chart.
Upgrading a Helm chart will upgrade its services to the versions specified in the chart. For example, to upgrade the seba-services Helm chart to v1.0.3, assuming that has been published to the online chart repository:
helm upgrade --version=1.0.3 --reuse-values \ seba-services cord/seba-services
The --reuse-values flag instructs Helm to pass in the same values used when installing the original chart. If you want to specify a different set of values, you can omit this and instead specify new values using -f myvalues.yaml.
In order to upgrade a running micro-service to a new version, it's necessary to update the Helm chart used to launch the service to specify the new Docker image repository and/or tag. One way to do this is by upgrading the chart that was initially used to launch the service as mentioned above. However some charts (like seba-services) install multiple sub-charts, each of which installs its own XOS service. How can an operator upgrade a single service?
An easy way to do this is with Helm's --set argument. To do this it's necessary to understand how the sub-chart specifies its image name and tag, as well as how the charts are nested. Using seba-services as an example, suppose that we have installed seba-services v1.0.2, and we want to upgrade the fabric-crossconnect service it installs from v1.1.4 to v1.1.5 without upgrading the seba-services chart to a new version. We can do so with this command:
helm upgrade --version=1.0.2 --reuse-values \ --set fabric-crossconnect.image.tag=1.1.5 \ seba-services cord/seba-services
The seba-services chart specifies the fabric-crossconnect chart as a requirement. The fabric-crossconnect chart's values.yaml file uses image.tag to specify the Docker image tag. So this command will pull down the new image and re-launch the fabric-crossconnect Kubernetes pod using this image.
As another example, v1.0.0 of the att-workflow chart runs the xosproject/att-workflow-driver:1.0.12 Docker image from Docker Hub. Suppose that you want to install image myrepo/att-workflow-driver:test-image in its place. To upgrade to this new image run:
helm upgrade --version=1.0.0 --reuse-values \ --set att-workflow-driver.image.repository=myrepo/att-workflow-driver --set att-workflow-driver.image.tag=test-image \ att-workflow cord/att-workflow
To verify that you're specifying the --set arguments correctly, you can replace helm upgrade with helm template in the above commands. This will print out all the Kubernetes resources that Helm generates, and you can check that the image has actually been updated in the resources.