fix(helm): quickstart deployment command nb of brokers

[leiicamundi]

Description

Fix quickstart instructions, related to https://camunda.slack.com/archives/C03UR0V2R2M/p1772126738381749

This pull request updates the quick installation instructions for Camunda 8 using Helm, clarifying the recommended cluster configuration when using the embedded H2 database as secondary storage. The changes ensure users configure a single-broker, single-partition cluster to avoid issues with the local nature of H2, and update the example Helm commands accordingly.

Documentation improvements for Helm installation:

• Updated the Helm install command examples in quick-install.md to explicitly set orchestration.clusterSize=1, orchestration.partitionCount=1, and orchestration.replicationFactor=1, ensuring a single-broker, single-partition setup when using embedded H2. [1] [2]
• Expanded the explanation to clarify that multiple brokers with embedded H2 would result in independent databases and incomplete query results, helping users avoid misconfiguration.

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support. (add bug or support label)
• This is already available but undocumented and should be released within a week. (add available & undocumented label)
• This is on a specific schedule and the assignee will coordinate a release with the Documentation team. (create draft PR and/or add hold label)
• This is part of a scheduled alpha or minor. (add alpha or minor label)
• There is no urgency with this change (add low prio label)

PR Checklist

• The commit history of this PR is cleaned up, using {type}(scope): {description} commit message(s)

• My changes are for an upcoming minor release and are in the /docs directory (version 8.9).
• My changes are for an already released minor and are in a /versioned_docs directory.

• I added a DRI, team, or delegate as a reviewer for technical accuracy and grammar/style:
  • Engineering team review
  • Technical writer review via @camunda/tech-writers unless working with an embedded writer.

[github-actions]

👋 🤖 🤔 Hello, @leiicamundi! Did you make your changes in all the right places?

These files were changed only in docs/. You might want to duplicate these changes in versioned_docs/version-8.8/.

• docs/self-managed/deployment/helm/configure/database/elasticsearch/using-external-elasticsearch.md
• docs/self-managed/deployment/helm/configure/database/using-external-opensearch.md
• docs/self-managed/deployment/helm/install/quick-install.md

You may have done this intentionally, but we wanted to point it out in case you didn't. You can read more about the versioning within our docs in our documentation guidelines.

[Copilot]

Pull request overview

Updates the Helm quick-install documentation to avoid misconfigured multi-broker Orchestration Cluster setups when using embedded H2 as RDBMS secondary storage.

Changes:

• Updates Helm install command examples to explicitly set orchestration.clusterSize=1, orchestration.partitionCount=1, and orchestration.replicationFactor=1.
• Expands the explanatory text to describe why embedded H2 requires a single-broker/single-partition setup.

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[giorgionaps]

Looks like some of the updates should be slightly reworded/reconciled with other docs. I'm requesting changes for now

[leiicamundi]

Thanks for the review @giorgionaps - I also edited the outdated pages, and fixed the directions around embedded elasticsearch that is now deprecated in 8.9

Happy to get your counter review!

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

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[ingorichtsmeier]

Looks good to me.

all good

[leiicamundi]

Thanks @christinaausley, can you re-approve it so it can be automerge? ty!

[github-actions]

The preview environment relating to the commit 5ac86e2 has successfully been deployed. You can access it at https://preview.docs.camunda.cloud/pr-8090/