mirror of https://github.com/linkerd/linkerd2.git
958d7983ac
In order to support an HA mode for the service-mirror component, some form of synchronization should be used to coordinate between replicas of the service-mirror controller. Although in practice most of the updates done by the replicas are idempotent (and have benign effects on correctness), there are some downsides, such as: resource usage implications from setting-up multiple watches, log pollution, errors associated with writes on resources that out of date, and increased difficulty in debugging. This change adds coordination between the replicas through leader election. To achieve leader election, client-go's `coordination` package is used. The change refactors the existing code; the previous nested loops now reside in a closure (to capture the necessary configuration), and the closure is run when a leader is elected. Leader election functions as part of a loop: a lease resource is created (if it does not exist), and the controller blocks until it has acquired the lease. The loop is terminated only on shutdown from an interrupt signal. If the lease is lost, it is released, watchers are cleaned-up, and the controller returns to blocking until it acquires the lease once again. Shutdown logic has been changed to rely on context cancellation propagation so that the watchers may be ended either by the leader elector (when claim is lost) or by the main routine when an interrupt is handled. --------- Signed-off-by: Matei David <matei@buoyant.io> Co-authored-by: Alejandro Pedraza <alejandro@buoyant.io> |
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| .. | ||
| service-mirror | ||
| testdata | ||
| allow.go | ||
| check.go | ||
| gateways.go | ||
| install.go | ||
| install_test.go | ||
| link.go | ||
| link_test.go | ||
| main_test.go | ||
| root.go | ||
| uninstall.go | ||
| unlink.go | ||