Operating a replica set: opt-in, metrics, and an RF=3 Docker demo in Squirix preview.9

Description and use

Squirix preview.9 operators must enable replication and failover, configure mTLS, and verify readiness via health endpoints and Prometheus metrics.

Problem

Operators need to enable, verify, and monitor Squirix replica set failover and metrics in a Docker Compose environment.

Outcome

The cluster achieves automatic failover, quorum reads, and exposes detailed replication metrics, enabling operators to monitor leader status, lag, and state transfers.

Workflow

• 1. Create Squirix.settings.json with ReplicaCount=3, PersistenceEnabled=true, ReplicationEnabled=true, AutomaticFailoverEnabled=true, QuorumReadsEnabled=true.
• 2. Configure mTLS certificates and CA bundle for inter-node authentication.
• 3. Validate configuration: squirix-server validate-config --settings ./Squirix.settings.json --strict.
• 4. Start each node with squirix-server run --settings ./Squirix.settings.json --persist --data-dir ./data --enable-replication ensuring all nodes are running before checking readiness.
• 5. Verify health endpoints /health, /health/ready, /health/ready/details and Prometheus metrics /metrics for replication status.
• 6. Use squirix-server doctor --settings ./Squirix.settings.json --persist --data-dir ./data to inspect topology stamp and metadata without starting the node.

Evidence

Setting ReplicaCount to three chooses how many copies hold a key. It does not enable durable storage, grant permission to replicate, or turn on elections.

Source

Replication has its own opt-in: Squirix:Cluster:ReplicationEnabled, default false, or the standalone-host flag --enable-replication.

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Automatic failover adds two settings, both off by default: AutomaticFailoverEnabled and QuorumReadsEnabled.

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The first activation of a fresh replica group needs every configured member, not just a majority.

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Readiness catches conditions such as unfinished journal recovery, a failed journal pipeline, or a detected ring mismatch.

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