Re: Postgresql fails to start? - Mailing list pgsql-general

Dianne Yumul <dianne@wellsgaming.com> writes:
> # rm -f pgstartup.log
> # /etc/rc.d/init.d/postgresql start
> /usr/bin/chcon: can't apply partial context to unlabeled file
> /home/postgres/pgstartup.log
> Starting postgresql service:                               [FAILED]
> # ps aux | grep postmaster
> postgres 10470 34.1  0.6 112404  5248 pts/0    S    09:24   0:02
> /usr/bin/postmaster -p 5432 -D /home/postgres/data
> root     10480  0.0  0.0   3756   668 pts/0    R+   09:24   0:00 grep
> postmaster

Odd.  I don't see any reason that you'd not get the OK message, given
that the postmaster started.  I've seen reports of that before, eg,
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=152931
but it's far from clear why some people see this and some don't.
In any case I suspect that the FAILED message is unrelated to the chcon
problem.

> ls -Z /home/postgres/pgstartup.log
> Gives:
> Sorry, this option can only be used on a SELinux kernel.

> But after setting selinux to permissive mode, ls -Z
> /home/postgres/pgstartup.log gives:

> -rw-------  postgres postgres system_u:object_r:postgresql_log_t
> /home/postgres/pgstartup.log

There is something very flaky about either your kernel or your selinux
utilities.  Are you up-to-date on kernel version?  (Let's see ... my
FC3 machine is at 2.6.11-1.14_FC3, and I think I may be behind ...)

I tried to reproduce the problem by doing what the initscript does,
without any success:

[tgl@rh1 ~]$ sudo mkdir /home/postgres
[tgl@rh1 ~]$ sudo chown postgres:postgres /home/postgres
[tgl@rh1 ~]$ PGLOG=/home/postgres/pgstartup.log
[tgl@rh1 ~]$ sudo touch "$PGLOG"
[tgl@rh1 ~]$ sudo ls -Z $PGLOG
-rw-r--r--  root     root     root:object_r:user_home_t        /home/postgres/pgstartup.log
[tgl@rh1 ~]$ sudo chown postgres:postgres "$PGLOG"
[tgl@rh1 ~]$ sudo chmod go-rwx "$PGLOG"
[tgl@rh1 ~]$ sudo /usr/bin/chcon -u system_u -r object_r -t postgresql_log_t "$PGLOG"
[tgl@rh1 ~]$ sudo ls -Z $PGLOG
-rw-------  postgres postgres system_u:object_r:postgresql_log_t /home/postgres/pgstartup.log
[tgl@rh1 ~]$ uname -r
2.6.11-1.14_FC3
[tgl@rh1 ~]$ rpm -qf /usr/bin/chcon
coreutils-5.2.1-31

so I suspect that what you are running into is either a kernel bug or a
chcon bug; it'd be worth making sure both kernel and coreutils are up to
date.  If you try the sequence by hand, what do you get?

>> Oh, and is the message really complaining
>> about /home/postgres/pgstartup.log?  AFAICS the initscript should be
>> messing with /var/lib/pgsql/pgstartup.log.

> Sorry, I forgot to mention that I changed some of the defaults via
> /etc/sysconfig/pgsql/postgresql file, which looks like this:
> PGDATA=/home/postgres/data
> PGLOG=/home/postgres/pgstartup.log

That is going to give you some problems if you have SELinux in
enforcement mode, because the standard policy will disallow the postgres
daemon from writing anywhere under /home.  You can fix this by fooling
around with the policy and/or manually relabeling the database directory
and files, but the path of least resistance is probably to leave the
database directory in the normal place.

            regards, tom lane