etcd

Microservices register their location (IP address and port) in etcd.

Other microservices query etcd to find the location of the desired service.

When a service instance changes its location, it updates its entry in etcd, and other services are notified via the Watch API.

Configuration settings are stored as key-value pairs in etcd.

Applications read the configuration settings from etcd at startup and whenever changes occur.

Changes to configuration settings are propagated to all application instances via the Watch API.

Multiple nodes attempt to acquire a lock in etcd to become the leader.

The first node to acquire the lock becomes the leader.

If the leader fails, the lock is automatically released, and another node is elected as the new leader.

A process attempts to acquire a lock in etcd before accessing the shared resource.

If the lock is available, the process acquires it and proceeds to access the resource.

Once the process is finished, it releases the lock, allowing other processes to acquire it.

Metadata is stored as key-value pairs in etcd, with the key representing the resource ID and the value representing the metadata.

Applications query etcd to retrieve metadata about specific resources.

Changes to metadata are propagated to applications via the Watch API.