Overview
In the Casablanca release ONAP has become very large with many Helm charts ( ~6 x that of Amsterdam ). Every Helm chart contains some amount of external configuration and, unfortunately, there is a limit to the amount of configuration that can exist in a Helm chart (1 MB). As of Casablanca, we in ONAP have exceeded this limit.
ONAP is installed as an umbrella (ie. parent) chart containing many subcharts, each with configuration. The total amount of configuration that resides in configmaps within K8s (exceeding 1MB) causes an installation of ONAP to fail. To work around this issue, a Helm plugin has been introduced that will install/upgrade ONAP by deploying the parent chart and each subchart within its own Helm "release". It is important to note that all releases must be deployed within the same Kubernetes namespace in order for communication between the components to succeed.
Disclaimer:
The plugins described here were introduced to address config map limitations in the Casablanca release. There are alternative projects, such as https://github.com/roboll/helmfile, that can also solve this problem.
The decision to not use an existing project was due to:
- not wanting to introduce a new project-specific deployment specification this late in the release cycle
- the desire to stay as close to an existing Helm solution as possible (we anticipate significant improvements in Helm 3)
That said, the use of deploy and undeploy plugins can be viewed as a temporary solution. In their current state, they have not been hardened (eg. resilient to networking errors) but are made available to unblock installation of ONAP. To avoid networking errors that can cause some of the sub-charts to fail to deploy, it is recommend that Helm deploy and undeploy commands execute from within the same network (e.g Rancher node or Jumpnode) as the K8s cluster you are deploying to.
Installing Helm Plugins (deploy & undeploy)
Clone oom repository
Copy oom/kubernetes/helm/plugins directory into your local ~/.helm/ folder.
cp -R ~/oom/kubernetes/helm/plugins/ ~/.helm
Verify plugins are installed correctly
Execute 'helm' (no arguments) should show both 'deploy' and 'undeploy' in list of available commands.
> helm ....... Usage: Available Commands: dependency manage a chart's dependencies template locally render templates |
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Helm Deploy Plugin
Deploying ONAP from public Helm Chart Repository
Example is using one of the public Helm Chart repos https://nexus.onap.org/content/sites/ (ie. staging).
Prerequisite:
- helm repo add staging https://nexus.onap.org/content/sites/oom-helm-staging/
helm deploy demo staging/onap --namespace onap
Deploying ONAP from cloned OOM codebase
Prerequisites:
- clone oom repository
- cd oom/kubernetes
- make repo
- make; make onap
helm deploy demo local/onap --namespace onap
or
helm deploy demo ./onap --namespace onap
Deploy Results
ONAP pods deployed into the 'onap' Kubernetes namespace. Each application project is installed as a Helm Release that is prefixed by the parent release name (e.g. "demo-")
> helm list |
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Advanced uses of Deploy Plugin
Not that any overrides that can be used using Helm install or update can still be applied.
helm deploy demo local/onap --namespace onap -f ~/overrides.yaml --set vid.enabled=false
Helm Undeploy Plugin
helm undeploy demo --purge