A distributed system, if the guarantee of access idempotency
Like solutions and ensure messages idempotency way, for example with an order to resolve multiple requests. The solution is to first generate a globally unique algorithm by snowflakes order ID, and then when writing database to determine whether there has been insert the order ID, if they have to give up direct insert operation.
Second, distributed systems, how to ensure that the order of the task
Two ways:
1. Add a service center through which the service to control their calling sequence, the message is sent to Service Award mq, in order to guarantee the order of the messages.
2. Distributed Lock
Third, the distributed coordination between the various service calls
Fourth, to achieve high availability by HA zookeeper
This should be very common, such as hadoop, hdfs, yarn and many large data systems zk are selected based on HA high availability to develop mechanisms is an important process will generally call the shots prepared two main processes hung up immediately perceived by zk switch to the backup process.
Fifth, distributed session data problem
I suggest putting the data into the redis inside, other machines when the request directly to redis which read data.
Sixth, the solution distributed transactions
spring + JTA transaction is implemented in two phases - the "first asks if the individual services can be executed -" and then execute, submit
TTC program, handwritten business rollback.
Rollback message by the middleware.
