pglogical setup in cascade replication architecture

[Perumal Raj]

Hi Team,

I have cascade level streaming replication & WAL Apply setup .

*Primary -> Secondary 1 -> Secondary 2,Secondary 3*
*WAL Archive -> Secondary 4*

I am expanding setup by adding another Replica from *Primary -> Secondary 5*
for logical streaming.

Do I need to install and configure pglogical on all the cluster nodes ?

Or just need between *Primary and Secondary 5 ?*

What will happen if I miss pglogical configuration in any one of the
Secondary node?

Version : >=  9.6

Please share your experience.

Thanks