DISCLAIMER: This is for postgresql 10 and ubuntu 18.04, and may or may not work for other versions.

Follow the answer provided by Mr Robot except recognize:

• The user and group are postgres, so the commands should use chown -R postgres:postgres ...
• I'm not sure what's up with /lib/systemd/system/postgresql.service which I edited to become:

    # systemd service for managing all PostgreSQL clusters on the system. This
    # service is actually a systemd target, but we are using a service since
    # targets cannot be reloaded.
    
    [Unit]
    Description=PostgreSQL RDBMS
    
    [Service]
    User=postgres
    Group=postgres
    Type=oneshot
    ExecStart=/usr/lib/postgresql/10/bin/pg_ctl start -D /etc/postgresql/10/main -l /etc/postgresql/10/main/postgresql.log
    ExecReload=/usr/lib/postgresql/10/bin/pg_ctl reload
    RemainAfterExit=on
    
    [Install]
    WantedBy=multi-user.target

which can be run by systemctl daemon-reload and service postgresql start although somehow it was already running? Again, I'm not so familiar with how a PostgreSQL cluster works so possibly this service change is entirely unnecessary, I don't know.

DISCLAIMER: This is for postgresql 10 and ubuntu 18.04, and may or may not work for other versions.

Follow the answer provided by Mr Robot except recognize:

• The user and group are postgres, so the commands should use chown -R postgres:postgres ...
• I'm not sure what's up with /lib/systemd/system/postgresql.service although somehow /lib/systemd/system/[email protected] manages a PostgreSQL cluster? Either way I guess it was already running by the time I followed the instructions, and after reboot (which should be unnecessary?) it came back online, so I guess it works.

Follow the answer provided by Mr Robot except recognize:

• The user and group are postgres, so the commands should use chown -R postgres:postgres ...
• I'm not sure what's up with /lib/systemd/system/postgresql.service which I edited to become:

    # systemd service for managing all PostgreSQL clusters on the system. This
    # service is actually a systemd target, but we are using a service since
    # targets cannot be reloaded.
    
    [Unit]
    Description=PostgreSQL RDBMS
    
    [Service]
    User=postgres
    Group=postgres
    Type=oneshot
    ExecStart=/usr/lib/postgresql/10/bin/pg_ctl start -D /etc/postgresql/10/main -l /etc/postgresql/10/main/postgresql.log
    ExecReload=/usr/lib/postgresql/10/bin/pg_ctl reload
    RemainAfterExit=on
    
    [Install]
    WantedBy=multi-user.target

which can be run by systemctl daemon-reload and service postgresql start although somehow it was already running? Again, I'm not so familiar with how a PostgreSQL cluster works so possibly this service change is entirely unnecessary, I don't know.

DISCLAIMER: This is for postgresql 10 and ubuntu 18.04, and may or may not work for other versions.

Follow the answer provided by Mr Robot except recognize:

• The user and group are postgres, so the commands should use chown -R postgres:postgres ...
• I'm not sure what's up with /lib/systemd/system/postgresql.service which I edited to become:

    # systemd service for managing all PostgreSQL clusters on the system. This
    # service is actually a systemd target, but we are using a service since
    # targets cannot be reloaded.
    
    [Unit]
    Description=PostgreSQL RDBMS
    
    [Service]
    User=postgres
    Group=postgres
    Type=oneshot
    ExecStart=/usr/lib/postgresql/10/bin/pg_ctl start -D /etc/postgresql/10/main -l /etc/postgresql/10/main/postgresql.log
    ExecReload=/usr/lib/postgresql/10/bin/pg_ctl reload
    RemainAfterExit=on
    
    [Install]
    WantedBy=multi-user.target

which can be run by systemctl daemon-reload and service postgresql start although somehow it was already running? Again, I'm not so familiar with how a PostgreSQL cluster works so possibly this service change is entirely unnecessary, I don't know.