Mysql HA with innodb

[Rupjit Das]

I am working in a project where our product will support mysql HA using innodb engine. However i have some query if anyone could help me it will help me:

1:If we have one primary node in the the cluster and the primary node is down the some other node is promoted to primary node but it will take some fraction of second to do this so if some r/w transaction happens at the same time, it fails is there any workaround for this or we need to set up the cluster with more than one primary node.

2: Suppose we have multiple router pointing to same mysql innodb cluster, and in jdbc url we are using the multiple router's ip to communicate so that if any router fails it switches to next router, however if some r/w operation is going on and one of the router fails then some of the r/w operation fails for fraction of second.Can this be handeled?