[feature: gsoc26] Add installation and configuration support for InfluxDB 2.0 and Elasticsearch

[pushpitkamboj]

Currently ansible-openwisp2 only supports provisioning InfluxDB 1.8 as the time-series backend. This issue tracks adding installation roles and configuration variables for both InfluxDB 2.0 and Elasticsearch, so operators can switch between all three backends via a single environment variable with no manual installation steps required.

Scope

• Add Ansible installation and configuration support for InfluxDB 2.0.
• Add Ansible installation and configuration support for Elasticsearch.
• Allow operators to choose between InfluxDB 1.8, InfluxDB 2.0, and Elasticsearch through the documented Ansible variables.
• Keep the Ansible variable names aligned with the monitoring-side backend configuration.
• Provide sane defaults for basic deployments.
• Allow advanced configuration for production deployments.

InfluxDB 2.0 options to cover

• URL or host/port configuration.
• Organization.
• Token handling.
• Bucket name.
• Retention configuration.
• Any required initialization needed for a working default deployment.

Elasticsearch options to cover

• Hosts.
• Scheme.
• Authentication or API key options.
• Index name.
• Index Lifecycle Management policy options if supported.
• Shard and replica settings if exposed.
• Mapping-related settings if they need to be configurable.

Acceptance criteria

• A fresh Ansible deployment can provision and configure InfluxDB 2.0 without manual installation steps.
• A fresh Ansible deployment can provision and configure Elasticsearch without manual installation steps.
• Operators can switch among InfluxDB 1.8, InfluxDB 2.0, and Elasticsearch with the documented variable or variables.
• Sane defaults work for a basic setup out of the box.
• Advanced settings can be overridden for production deployments.
• The generated OpenWISP Monitoring configuration matches the backend selected by the operator.

[nemesifier]

I updated the issue body to make the Ansible deployment scope and acceptance criteria more explicit.

The changes add backend-specific configuration options, sane default expectations, advanced configuration expectations, and validation that deployments can switch between the supported timeseries backends through documented variables.

To review the body changes, navigate to the top bar of the issue body, click last edited by nemesifier, then click most recent to review the edit history. Unfortunately there is no quick URL I can share for this view.

[cbeaujoin-stellar]

The ansible-openwisp2 should rely on https://github.com/openwisp/ansible-ow-influxdb