Monit (fix /var/log/messages)

Recently I discovered monit for FreeBSD, a monitoring system that is highly configurable and can be used to monitor various system happenings including service checks, disk space usage and process health. I installed it on all of the systems we have that require such monitoring. It has been very helpful in letting us know when things go offline.

The one issue I have noticed with it has to do with monitoring PostgreSQL. The PostgreSQL part of our config is setup like so:

# POSTGRESQL
check host PostgreSQL with address 127.0.0.1
    if failed ping then alert
    if failed port 5432 protocol pgsql then alert

So when it can’t connect to PostgreSQL we will receive an email message about it. Great! However if you look in the /var/log/messages you will notice something like this every 30 seconds (since we have monit setup to check everything in 30 second intervals):

Nov  1 00:12:41 blackbox postgres[70271]: [2-1] FATAL:  role "root" does not exist

To fix this and start cleaning up our log its pretty straight forward. Create that role:

psql -U pgsql template1
create role root login nocreaterole nocreatedb nosuperuser noinherit;

After this we now start seeing this error in the log:

Nov  9 12:47:50 blackbox postgres[94875]: [2-1] FATAL:  database "root" does not exist

To fix this we simple create that database:

create database root;

I also added this to the pg_hba.conf:

# TYPE  DATABASE        USER            ADDRESS                 METHOD
...
host    root            root            127.0.0.1/32            trust
...

That fixed our issues and now we no longer see those /var/log/messages. Monit wants to always connect using the “root” user and there’s no way to configure it to use a different user. So I came up with this as the workaround.

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NTP attack

Yep we got bit by this one. It brought our network to its knees. Fortunately the fix was easy. First, to stop the attack we turned off ntp temporarily:

service ntp stop

Then we added this to our /etc/ntp.conf file:

Disable monitor
Restrict -4 default kod notrap nomodify nopeer noquery

Then we started ntp:

service ntp start

The system returned to normal.

FreeBSD update broke Apache perl modules

After a recent freebsd update fetch && freebsd update install Apache would not restart properly. It was complaining about missing perl modules it relied on. So we rebuilt the perl port and all its dependencies.

sudo portmaster -m BATCH=yes --no-confirm -D -r perl

The -m BATCH=yes chooses defaults at setup screens and bypasses them, --no-confirm avoids prompting at the command line, -D keeps distfiles in tact and -r updates all its port dependencies. Once this was done Apache fired right up!