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Quorum queues use Raft consensus to replicate RabbitMQ messages across nodes. Here's how to declare one, prove failover works, and decide when the latency trade-off is worth it.
Learn how to run Mattermost in high‑availability mode using Docker Swarm, with shared PostgreSQL and MinIO, automatic failover, and the trade‑offs you must manage.
Context Harvester v1.3–1.4 officially supports single-node clusters for development and edge scenarios. The installer provisions an embedded etcd member and sets the Longhorn default replica count to 1. For production HA, the documented path requires at least three server nodes, a 3-member etcd cluster, and a Longhorn default replica count of 3 with anti-aff
Migration leadership and lock ownership In a Mattermost high-availability cluster running v8.x, the first node to start acquires a PostgreSQL advisory lock and executes pending database migrations while other nodes block on the same lock. The documentation states that only the leader runs migrations, but it does not specify what happens to the advisory lock
Goal The cluster should continue to accept writes even when a node goes down, maintaining the configured replication‑factor. Constraints & Uncertainty Replication‑factor is set to 3 but the cluster only has 2 active nodes. The write operation blocks and errors appear in the logs. It is unclear whether the failure is due to the replication‑factor exceedin
The goal is to determine whether Proxmox VE’s HA manager can safely retry a failed VM resource without causing duplicate writes to shared storage when the original node loses contact. Current documentation shows that HA stops the failed resource before relocation and relies on the storage layer for consistency, but it does not provide an idempotent retry mec
Goal Migrate a small Mattermost application to a newer server version while keeping the API and web client available, using database schema migration and configuration changes already supported by the server. Constraints Mattermost applies supported schema migrations automatically during startup, but a single application node does not accept traffic while th
Database Schema Migration in HA Environments Apache Airflow 2.0+ supports high availability (HA) by running multiple schedulers simultaneously. While this architecture allows for rolling restarts of the scheduler components, the underlying metadata database migrations performed via airflow db upgrade are not transactional across the cluster. Consistency Risk
Integration Boundary Prometheus HA replicas each expose firing and resolved alerts to a shared Alertmanager via the Prometheus Alerting API at /api/v1/alerts . Alertmanager deduplicates incoming alerts by comparing label sets, treating alerts with identical labels as a single group for notification purposes. Unresolved Behavior The deduplication logic is ver
rancher
kubernetes
mattermost
aerospike
prometheus
rabbitmq