Working with Postgres from the Command Line in Lion Server

Mac OS X Server 10.7, Lion Server, comes with a few substantial back-end changes. One of these is the move from SQLite3 to PostgreSQL for many of the back-end databases, including Wiki and Podcast Producer (collab), Webmail (roundcubemail), iCal Server and Address Book Server (caldav) and as the back-end to the newest service in Lion Server, Profile Manager (device_management). As such, it’s now important to be able to use PostgreSQL the way we once used SQLite3, when trying to augment the data that these databases contains, as there currently aren’t a lot of options for editing this data (aside from manually of course).

Postgres has a number of commands that can be used to interact with databases. The most important is probably psql. Many of the other commands simply provide automated options to psql, and over time I’ve started using psql for most everything. For example, PostgreSQL comes with a command /user/bin/createuser. However, as it’s usually more verbose with errors, I like to use psql to do this. In Lion Server, the only user that can access the Postgres databases is _postgres, installed by default with Lion Server. Because a lot of commands require passwords and we might not always want to provide write access to the databases, we’re going to create a new SuperUser, called krypted with a password of daneel.

To do so, we will have to use the _postgres user to invoke psql. Any time you want to invoke psql with a different user than the user you are currently logged in as, use the -U option. To define a database, use the -d option (device_management providing access to Profile Manager data, caldav to iCal Server data roundcubemail to WebMail data and collar to Wiki data). To string this together, for accessing the device_management database as _postgres:

psql -U _postgres -d device_management

To then create a new user called krypted with a password of daneel we’ll use the create option, defining a user as the type of object to create, followed by the user name and then with password followed by the password (single quoted) and then createuser; as follows:

device_management=# create user krypted with password 'daneel' create user;

Now that there’s a valid user, let’s see what else we can do. To see all of the tables, use d:

device_management=# d

As you can tell, there are a bunch of them. Run the help command to see a list of SQL commands that can be run and ? for a list of psql options. To put some SQL commands into action, we’re going to look at the tasks that have been performed by Profile Manager. These are stored in the tasks table (aptly named), so we’re going to run the following SQL query (note a space followed by a semi-colon is required at the end of this thing):

device_management=# select * from "public"."tasks" limit 1000 offset 0 ;

Or to make it a bit simpler if you don’t have a lot of data in there yet:

device_management=# select * from "public"."tasks" ;

After seeing the output, you’ll probably be a little appreciative of Apple’s formatting. Next, let’s look at dumping the databases. We’re going to create a folder on the root of the volume called db_backups first:

sudo mkdir /db_backups

This is where these backups will end up getting stored. We’ll continue using the _postgres user for now. To do our database dumps, we’re going to use pg_dump, located at /usr/bin. First, we’ll dump the device_management database (but first we’ll stop the service and after we’ll start it – all commands from here on out also assume you’re sudo’d):

serveradmin stop devicemgr
pg_dump -U _postgres device_management -c -f /db_backups/device_management.sql
serveradmin start devicemgr

And the other 3 (stopping and starting each in the process):

serveradmin stop web
pg_dump -U _postgres roundcubemail -c -f /db_backups/roundcubemail.sql
serveradmin start web
serveradmin stop wiki
pg_dump -U _postgres collab -c -f /db_backups/collab.sql
serveradmin start wiki
serveradmin stop addressbook
serveradmin stop calendar
pg_dump -U _postgres caldav -c -f /db_backups/caldav.sql
serveradmin start addressbook
serveradmin start calendar

I haven’t had any problems running the dumps with the services running, but it’s better safe than sorry I guess. I’d probably also add some logging and maybe dump the output of full status for each service to try and track if all is well with each. Any time a service didn’t fire back up I’d then build in a sanity check for that event. There’s also a database for postgres itself, so let’s back that up as well since we’re here:

pg_dump -U _postgres postgres -c -f /db_backups/postgres.sql

These can then be restored using psql with the -d option to define the database being restored into and the -f option to define the file being restored from. For example, to restore collab:

psql -U _postgres -d collab -f /db_backups/collab

The databases are all dumped daily using pg_dumpall. These are stored in /var/pgsql but can be changed using serveradmin settings (for example, to move them to /var/pgsql1):

serveradmin settings postgres:dataDir = "/var/pgsql1"

If you mess up the Profile Manager database (before you put any real data into it) you can always use the /usr/share/devicemgr/backend/wipeDB.sh script to trash the database and start anew (although I’d just use a snapshot of a VM for all this and restore from that).

You can also connect to Postgres remotely, or locally through a network socket (common in Apache uses) by adding a listener. To do so, we’ll need to restart the Postgres LaunchDaemon. First, back up the file, just in case:

cp org.postgresql.postgres.plist org.postgresql.postgres.plist.OLD_CSE

Then stop postgres:

serveradmin stop postgres

Then edit the org.postgresql.postgres.plist file to change the following line:

listen_addresses=

To read:

listen_addresses=127.0.0.1

Then fire up postgres again:

serveradmin start postgres

And now let’s scan port 5432 (the default TCP and UDP port used for postgres) for localhost:

/Applications/Utilities/Network Utility.app/Contents/Resources/stroke 127.0.0.1 5432 5432

We could have used another IP address for the listen_addresses as well, but with that _postgres user not requiring a password it didn’t really seem prudent to do so. Once you’ve enabled a socket, you’ll then be able to use one of the many GUI tools to manage postgres. Navicat is available on the Mac App Store for $5 and PGnJ is a nice, easy to use, free one. There are tons of others, but I don’t spend a lot of time in a SQL GUI and so don’t need more than a cheap app will get me. One nice thing about most of these is that they help you to form SQL queries (or they help me). This can get really nice if you are, for example, trying to get some good reporting on Profile Manager (a feature it’s a bit light on right now).

Finally, don’t do any of this stuff on a production box, except maybe if you want more than nightly backups unless you think pretty hard about what you’re doing and know the exact impact of doing something. If you were to edit the databases on a live boxen, then you can safely assume that with how all of the objects in those databases use GUIDs that you’re probably going to break something, if not bring the whole house of cards tumbling down.

9 Comments

  • Pingback: Removing Apps from Profile Manager Using Postgres | Krypted.com

  • Ervin Miller
    February 10, 2012 - 11:15 am | Permalink

    Love the content.

    Speaking from budget-constrained K12 school district perspective, Profile Manager seems ripe for an open source reporting companion application. I don’t have those skills.

    A couple of corrections and one clarification.
    The clarification:
    Have to su or sudo when running psql or I get:
    “psql: could not connect to server: Permission denied
    Is the server running locally and accepting
    connections on Unix domain socket “/var/pgsql_socket/.s.PGSQL.5432″?”

    Corrections:
    “For example, PostgreSQL comes with a command /user/bin/createuser. ” That path should be /usr/bin/createuser. (usr without an e)
    and
    “device_management=# create user krypted with password ‘daneel’ create user;” Should be “device_management=# create user krypted with password ‘daneel’ createuser;”
    (no space between the last create and user)

  • Timothy Turner
    April 7, 2012 - 5:50 am | Permalink

    These are some really good articles. I have a question about the relationship between the device_management db and printers in system preferences. Do you know what mechanism triggers the change in printed list under system preferences and printers in device_management db?

    Tim.

    • June 28, 2012 - 9:50 pm | Permalink

      You mean is the list populated from the server or the client? If so it’s populated from the printer list on the server. The change in printers comes each time you invoke the screen, or if that’s not working clear out the web cache in Safari. Good luck.

  • Arlo Vanderbel
    June 12, 2012 - 4:54 pm | Permalink

    in mountian lion server you can add the listeners using the serveradmin cli rather then editing the org.postgresql.postgres.plist.

    $ sudo serveradmin settings postgres:listen_addresses = “127.0.0.1″

  • Mac
    August 4, 2012 - 4:03 am | Permalink

    Hi,

    this is a great article, is there some way i can request a task UpdateInformation to of all devices from command line.

    -
    Mac

    • August 27, 2012 - 8:25 pm | Permalink

      I wish. I’m guessing it could be scripted. I need to do another post on that soon, as I’ve got a bunch of new recipes for triggering events… Might help guide you in that direction.

  • Matt Domenici
    October 21, 2012 - 5:15 pm | Permalink

    Do you have an updated set of instructions for Mountain Lion? I cannot seem to locate this plist file any longer… (Sorry, relatively new to ML!)

  • Todd
    October 26, 2012 - 10:09 am | Permalink

    FYI: Mountain Lion stopping the devicemgr unfortunately kills the postgres process…

  • Comments are closed.