Enabling Maintenance mode

As because we have noticed that there was a downtime of 9 Server Nodes yesterday and the load balancers still sent request to those which were down, we noticed that our load balancer's configurations are off.

The Load Balancers should've been configured to not forward any traffic to MarcSync Endpoints which aren't avaliable/reachable. However, they still forwarded them to those.

We found our configuration flaw and wanted to fix it however, this caused a downtime of round about 10 minutes. We haven't expected that this may cause a downtime and decided to cancel and shedule a maintenance for that operation instead.

Downtime for that maintenance operation must be expected.