Failed to create target cluster during upgrade 9.5 to 9.6

I am on ubuntu 16.04 and have postgres 9.5 installed on it

Then I upgrade postgres 9.5 to 9.6 and I follow the postgresql official download page to install 9.6:

then i run apt install postgresql-9.6

, after installation run following commands to update

# stop the 9.6 
$ sudo pg_dropcluster 9.6 main --stop

# upgrade 9.5 to latest version
$ sudo pg_upgradecluster 9.5 main

sudo pg_upgradecluster 9.5 main
Stopping old cluster...
Notice: extra pg_ctl/postgres options given, bypassing systemctl for stop operation
Disabling connections to the old cluster during upgrade...
Restarting old cluster with restricted connections...
Redirecting start request to systemctl
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = "en_US:en",
    LC_ALL = (unset),
    LC_CTYPE = "UTF-8",
    LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").
Error: The locale requested by the environment is invalid.
Error: Could not create target cluster

      

        
        
        
      

    

Then I try to use the command psql

to connect the old cluster. but errors:

$ psql -U postgres -h localhost
psql: FATAL:  no pg_hba.conf entry for host "::1", user "postgres", database "postgres", SSL on
FATAL:  no pg_hba.conf entry for host "::1", user "postgres", database "postgres", SSL off

      

        
        
        
      

    

It seems that pg_hba.conf is wrong, then I check pg_hba.conf against /etc/postgresql/9.5/main/pg_hba.conf

, but it looks ok:

local   all             postgres                                peer