Better documentation of podDisruptionBudget for Elasticsearch.spec

[vanny96]

As described in the comments at pkg/controller/elasticsearch/pdb/reconcile.go "The default PDB we setup dynamically adapts MinAvailable to the number of nodes in the cluster."

The documentation should reflect this default value, as the current one is misleading and leads to a very different behaviour.

[thbkrkr]

Thank you for the report. This is related to #1775 where we didn't update the documentation.

The default PodDisruptionBudget is a not exactly what you wrote.

By default, the operator sets MinAvailable to NumberOfPods - 1, so only one Pod can be disrupted.
However, in cases such as:

• cluster not green (best-effort based on potential out-of-date information)
• only 1 master node
• only 1 data node

MinAvailable is set to NumberOfPods, so no Pod can be disrupted.

We also need to update the description in the values.yaml file of the eck-elasticsearch Helm chart.

cloud-on-k8s/deploy/eck-stack/charts/eck-elasticsearch/values.yaml

Line 129 in ac28d19

# By default, if not set, the operator sets a budget that selects all Elastisearch cluster pods and sets `maxUnavailable` to 1.

[vanny96]

Sorry for the late reply
Just updated the description in both the helm chart values.yaml and in the docs file. I'm not sure of the phrasing, as I was trying to keep it as short as possible while still conveying the correct information. What do you think? I wouldn't mind someone coming up with better messages!

[thbkrkr]

buildkite test this

[thbkrkr]

@elasticmachine run elasticsearch-ci/docs

[thbkrkr]

I'm not sure of the phrasing, as I was trying to keep it as short as possible while still conveying the correct information. What do you think?

Your proposal is very good, we will take it as such. I just moved the description into the code and regenerated everything from that. Thanks again for the contribution.