The default, which is /tmp, has a few issues associated with it:
One being that it makes it easy for users on the system to spoof a
PostgreSQL server if it's not running, causing applications to connect
to their provided sockets instead of just failing to connect.
Another one is that it makes sandboxing of PostgreSQL and other services
unnecessarily difficult. This is already the case if only PrivateTmp is
used in a systemd service, so in order for such a service to be able to
connect to PostgreSQL, a bind mount needs to be done from /tmp to some
other path, so the service can access it. This pretty much defeats the
whole purpose of PrivateTmp.
We regularily run into issues with this in the past already (one example
would be https://github.com/NixOS/nixpkgs/pull/24317) and with the new
systemd-confinement mode upcoming in
https://github.com/NixOS/nixpkgs/pull/57519, it makes it even more
tedious to sandbox services.
I've tested this change against all the postgresql NixOS VM tests and
they still succeed and I also grepped through the source tree to replace
other occasions where we might have /tmp hardcoded. Luckily there were
very few occasions.
Signed-off-by: aszlig <aszlig@nix.build>
Cc: @ocharles, @thoughtpolice, @danbst
This allows, finally, proper detection when postgresql is ready to
accept connections. Until now, it was possible that services depending
on postgresql would fail in a race condition trying to connect
to postgresql.
This reverts commit 095fe5b43d.
Pointless renames considered harmful. All they do is force people to
spend extra work updating their configs for no benefit, and hindering
the ability to switch between unstable and stable versions of NixOS.
Like, what was the value of having the "nixos." there? I mean, by
definition anything in a NixOS module has something to do with NixOS...
`nixos-option` evals the description and the '`' is used to
define shell commands.
Due to this, the following error appears:
```
$ nixos-option services.postgresql.superUser
Value:
"root"
Default:
"root"
Description:
/run/current-system/sw/bin/nixos-option: line 294: root: command not found
/run/current-system/sw/bin/nixos-option: line 294: postgres: command not found
NixOS traditionally used as superuser, most other distros use .
From 17.09 we also try to follow this standard. Internal since changing this value
would lead to breakage while setting up databases.
```
* postgresql service: make 9.6 the default version for 17.09
* postgresql service: change default superuser for 17.09
Change the default superuser from `root` to `postgres` for state
version 17.09
* postgresql service: change default data directory for 17.09
The new directory includes the schema version of the database.
This makes upgrades easier and is more consistent with other distros.
* updated nixos release notes
Fixes#15512 and #16032
With the multi output, postgresql cannot find at runtime what is its
basedir when looking for libdir and pkglibdir. This commit fixes that.
Regression introduced by b21fd5d066.
The initialScript is only executed whenever there is a .first-startup in
the dataDir, so silently dropping the file essentially breaks
initialScript functionality.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Authentication methods are tried in order, so if another NixOS module
defines a specific ident mapping like
local hydra all ident map=hydra-users
it should appear before the generic
local all all ident
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
The postgresql module has a postStart section that waits for a database
to accept connections before continuing. However, this assumes various
properties about the database - specifically the database user
and (implicitly) the database name. This means that for old
installations, this command fails because there is no 'postgres' user,
and the service never starts.
While 7deff39 does create the 'postgres' user, a better solution is to
use `pg_isready`, who's sole purpose is to check if the database is
accepting connections. This has no dependency on users, so should be
more robust.
Old PostgreSQL installations were created using the 'root' database
user. In this case, we need to create a new 'postgres' account, as we
now assume that this is the superuser account.
Unfortunately, these machines will be left with a 'root' user as
well (which will have ownership of some databases). While PostgreSQL
does let you rename superuser accounts, you can only do that when you
are connected as a *different* database user. Thus we'd have to create a
special superuser account to do the renaming. As we default to using
ident authentication, we would have to create a system level user to do
this. This all feels rather complex, so I'm currently opting to keep the
'root' user on these old machines.
as per postgresql manual, interactions with psql should be carried
out with the postgresql system user and postgresql db user by default.
ensure it happens in postStart.
PostgreSQL defaults to having 'postgres' as the superuser. NixOS should
use this default name to provide a less surprising result to people who
enable services.postgres.
Postgres was taking a long time to shutdown. This is because we were
sending SIGINT to all processes, apparently confusing the autovacuum
launcher. Instead it should only be sent to the main process (which
takes care of shutting down the others).
The downside is that systemd will also send the final SIGKILL only to
the main process, so other processes in the cgroup may be left behind.
There should be an option for this...
The attribute ‘config.systemd.services.<service-name>.runner’
generates a script that runs the service outside of systemd. This is
useful for testing, and also allows NixOS services to be used outside
of NixOS. For instance, given a configuration file foo.nix:
{ config, pkgs, ... }:
{ services.postgresql.enable = true;
services.postgresql.package = pkgs.postgresql92;
services.postgresql.dataDir = "/tmp/postgres";
}
you can build and run PostgreSQL as follows:
$ nix-build -A config.systemd.services.postgresql.runner -I nixos-config=./foo.nix
$ ./result
This will run the service's ExecStartPre, ExecStart, ExecStartPost and
ExecStopPost commands in an appropriate environment. It doesn't work
well yet for "forking" services, since it can't track the main
process. It also doesn't work for services that assume they're always
executed by root.
