Expert
Only the manager has the image
Last month the shop moved from one server to a three-node Docker Swarm. docker service ls says shop_api runs 3/3 and the shop answers. Tomorrow at 10:00, manager-1 is drained for its kernel patch, as RUNBOOK.md says: its tasks have to move to the workers. Make sure the shop survives that maintenance window.
Your terminal is on manager-1, the only manager; worker-1 and worker-2 complete the cluster. The company registry, registry.shop.internal, accepts pushes to the shop project. The test calls http://<cluster>/products every minute for two hours: at 0:30, docker node update --availability drain manager-1; at 1:30, the node is set back to active.
What your server must hold
- Availability ≥ 99 %