after apt update: Warning: No existing cluster is suitable as a default target.

[robert rottermann]

Hi there

i am on  a Ubuntu 16.04:

lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 16.04.7 LTS
Release:    16.04
Codename:    xenial

my postgresql was not updated in a while due to an error in the apt configuration.

After fixing it postgres13 was install, but now I get:

root at alice2 /etc/apt # psql
Warning: No existing cluster is suitable as a default target. Please see man 
pg_wrapper(1) how to specify one.
psql: error: could not connect to server: No such file or directory
     Is the server running locally and accepting
     connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?


pg_lsclusters shows:
Ver Cluster Port Status Owner    Data directory               Log file
9.5 main    5433 online postgres /var/lib/postgresql/9.5/main 
/var/log/postgresql/postgresql-9.5-main.log
9.6 main    5434 online postgres /var/lib/postgresql/9.6/main 
/var/log/postgresql/postgresql-9.6-main.log
13  main    5435 online postgres /var/lib/postgresql/13/main 
/var/log/postgresql/postgresql-13-main.log

how can I fix that?

thanks

robert