log repl exercise monitor setup

Hello,

i would like to setup a mass test environment for 250+ students

for example a setup with two clusters that we manage: cluster PUB and
cluster SUB

goal: on cluster PUB each student has its own database
mirrored/replicated to his own database at cluster SUB

starting point:
* the databases on cluster PUB already exist with content
* the empty databases on cluster SUB already exist (without any
content)
* no publication (and thus subscription is already running)

so the exercise for each student would be:
1. create publication
2. mirror the structure (backup/restore)
3. create subscription
4. test replication (with dml: insert/..)

So what would be your suggestion to setup an easy monitoring setup to
check that the student succeeded in this exercise

background: vanilla debian with postgres apt repository, preferable
with software from these repositories for security and maintenance
reasons

(at the moment i check with some handmade scripts that query the
cluster and the logs)

mvg,
Wim