pg_createcluster - create a new PostgreSQL cluster
pg_createcluster [options] versionname
pg_createcluster creates a new PostgreSQL server cluster (i. e. a
collection of databases served by a postmaster(1) instance) and
integrates it into the multi-version/multi-cluster architecture of the
Every cluster is uniquely identified by its version and name. The name can be
arbitrary. The default cluster that is created on installation of a server
main . However, you might wish to create other clusters for
testing, with other superusers, a cluster for each user on a shared server,
pg_createcluster will abort with an error if you try to create a
cluster with a name that already exists for that version.
Given a major PostgreSQL version (like ``8.2'' or ``8.3'') and a cluster
name, it creates the necessary configuration files in
/ ; in particular these are
pg_hba.conf , a postgresql-common
specific configuration file
start.conf (see STARTUPCONTROL below),
pg_ctl.conf , and a symbolic link
log which points to the log file (by
postgresql.conf is automatically adapted to use the next available port, i.
e. the first port (starting from 5432) which is not yet used by an already
If the data directory does not yet exist, PostgreSQL's initdb(1) command is
used to generate a new cluster structure. If the data directory already exists,
it is integrated into the postgresql-common structure by moving the
configuration file and setting the data_directory option. Please note that this
only works for data directories which were created directly with initdb, i.
e. all the configuration files (
postgresql.conf etc.) must be present in the
If a custom socket directory is given and it does not exist, it is created.
If the log file does not exist, it is created. In any case the permissions are
adjusted to allow write access to the cluster owner. Please note that
postgresql.conf can be customized to specify
log_filename ; if at least one of these options is present, then the symbolic
log in the cluster configuration directory is ignored.
If the default snakeoil SSL certificate exists
/etc/ssl/private/ssl-cert-snakeoil.key ), this program creates symlinks to
these files in the data directory (
server.key ) and enables
SSL for that cluster (option ssl in
postgresql.conf ). Therefore all
clusters will use the same SSL certificate by default. Of course you can
replace these symlinks with a cluster specific certificate.
Set the user who owns the cluster and becomes the database superuser to the
given name or uid. By default, this is the user postgres. A cluster must
not be owned by root.
Change the group of the cluster related data files. By default this will be the
primary group of the database owner.
Explicitly set the data directory path, which is used to store all the actual
databases and tables. This will become quite big (easily in the order of five
times the amount of actual data stored in the cluster). Defaults to
Explicitly set the directory where the postmaster(1) server stores the Unix
socket for local connections. Defaults to
/var/run/postgresql/ for clusters
owned by the user postgres, and
/tmp for clusters owned by other users.
Please be aware that
/tmp is an unsafe directory since everybody can create
a socket there and impersonate the database server. If the given directory does
not exist, it is created with appropriate permissions.
Explicitly set the path for the postmaster(1) server log file. Defaults to
Set the default locale for the database cluster. If this option is not
specified, the locale is inherited from the environment that
pg_createcluster runs in.
Like --locale, but only sets the locale in the specified category.
Select the encoding of the template database. This will also be the default
encoding of any database you create later, unless you override it there. The
default is derived from the locale, or SQL_ASCII if that does not work. The
character sets supported by the PostgreSQL server are described in the
Note: It is not recommended to set this option directly! Set the locale
Select the port the new cluster listens on (for the Unix socket and the TCP
port); this must be a number between 1024 and 65535, since PostgreSQL does not
run as root and thus needs an unprivileged port number. By default the next
free port starting from 5432 is assigned.
Immediately start a server for the cluster after creating it (i. e. call
pg_ctlcluster version cluster
start on it). By default, the cluster is
Set the initial value in the
start.conf configuration file. See STARTUPCONTROL below. By default, auto is used, which means that the cluster is
/etc/init.d/postgresql- version, i. e. starts and stops
automatically on system boot.
start.conf file in the cluster configuration directory controls the
start/stop behavior of that cluster's postmaster process. The file can contain
comment lines (started with '#'), empty lines, and must have exactly one
line with one of the following keywords:
The postmaster process is started/stopped automatically in the init script.
This is also the default if the file is missing.
The postmaster process is not handled by the init script, but manually
controlling the cluster with pg_ctlcluster(1) is permitted.
Neither the init script nor pg_ctlcluster(1) are permitted to start/stop the
cluster. Please be aware that this will not stop the cluster owner from calling
lower level tools to control the postmaster process; this option is only meant
to prevent accidents during maintenance, not more.
pg_ctl.conf file in the cluster configuration directory can contain
additional options passed to pg_ctl of that cluster.