Fencing Tokens and Generation Clock in .NET: Stop Zombie Leaders From Writing
Leader election and leases answer a comforting question: who should be in charge right now. They do not fully answer the dangerous question: who can still write right now. A node can lose its lease, another node can become leader, and the old leader can still push writes through an existing database connection. When that happens, your system is not …
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Lease Pattern in .NET: A Lock With an Expiration Date That Saves Your Data
Indefinite locks belong to a world where processes never crash and networks never split. That world does not exist. In a distributed system, “I hold the lock” can mean “I held the lock before my VM paused for 45 seconds.” A lease fixes that by putting a deadline on ownership and forcing the owner to keep renewing that claim. A …
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Leader Election in .NET: Picking One Boss Without Creating Two
If your service runs on more than one node and still has a single instance assumption, you already have leader election. You just do not have it on purpose. Leader election is the pattern that turns “somebody should run this” into “exactly one node is allowed to run this, and it must keep proving it deserves the role.” This post …
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Distributed System Pattern: Leader and Followers in .NET – One Decision Maker, Many Replicas, Fewer Outages
Distributed systems rarely fail because you picked the wrong cloud service. They fail because two nodes believe they are in charge, both act, and both are “correct” from their own perspective. If your domain has any single authority assumption, and most systems do, you need a way to make that authority real. Leader and Followers is the pattern that turns …
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Patterns of Distributed Systems in C# and .NET: A New Series for People Who Ship Real Systems
Distributed systems do not fail because you missed a feature. They fail because responsibility is unclear. Two nodes act, both think they are right, and your data becomes a debate. This series is my pushback against cargo cult architecture. We are going to talk about the small, repeatable techniques that stop outages, not the buzzwords that decorate slides. Unmesh Joshi’s …
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