Setting up a Postgres Sandbox

I’m a fan of disposable sandboxes using Vagrant and VirtualBox.

I’ve been using Postgres on the job for nearly a year, and a while back I decided it was time to have a dedicated Postgres instance on my personal computer, on a virtual machine, just to play around with.

I’m using a Mac, but the steps below should work without change for Windows or Linux. Let me know in the comments if you run into any problems following these steps!

How to set up a reproducible Postgres sandbox inside a disposable VM

  1. If you haven’t done so already, install Vagrant and VirtualBox.

  2. Choose a Vagrant base image. For my own purposes I chose the vanilla base box puppetlabs/centos-6.6-64-nocm (which comes from Puppet Labs but doesn’t have Puppet installed.)

    There are official images for CentOS and official images for Ubuntu as well, in addition to the vast range of user-contributed images. (The official CentOS image doesn’t come with VirtualBox guest additions installed, though, so folder syncing won’t work out of the box.)

    You don’t have to do anything with your choice just yet, just choose one.

  3. Open your terminal or command line environment.

  4. Create a dedicated directory for this particular Vagrant environment to live in, and change directories to that directory. (I personally use ~/term/vagrant/centos-6.)

    mkdir -p ~/term/vagrant/centos-6
    cd !$

    (!$ makes use of a Bash feature called “History Expansion.” It expands to the last portion of the last command executed, in this case ~/term/vagrant/centos-6.)

  5. Initialize the Vagrant environment, specifying the base image (box) you chose in step 2.

    vagrant init puppetlabs/centos-6.6-64-nocm

    You can run ls and observe that a Vagrantfile has been created:

    $ ls
  6. Bring up the Vagrant environment, which (this first time) will also download the base image you chose earlier.
    vagrant up

    This may take a little while. Wait for it.

  7. Log in to the Vagrant virtual machine you’ve created.

    vagrant ssh
  8. If you want a particular version of Postgres, choose the version of the Postgres yum repository package from which you can download the Postgres package itself. (I chose Postgres 9.3.) Right click and choose “copy link.” Then, inside your Vagrant VM, run the following command, replacing the URL with the one you’ve just copied.
  9. Install the package you’ve just downloaded.
    sudo yum install -y ./pgdg-redhat93-9.3-3.noarch.rpm
  10. Create a “packages” directory inside /vagrant, to store the Postgres packages outside the VM, where they will be saved when the VM is destroyed. Change to this directory.
    mkdir /vagrant/packages
    cd !$
  11. Download the Postgres packages (ignoring the versions present in the default repositories).
    yumdownloader --resolve --disablerepo=\* --enablerepo=pgdg\* postgresql\*-server
  12. Exit, and verify that the “packages” directory shows up on your host with three RPMs inside.
    ls packages
  13. Modify the Vagrantfile to include the shell commands to initialize Postgres.

    Change the commented out lines (near the bottom of the file) that read as follows:

      # config.vm.provision "shell", inline: <<-SHELL
      #   apt-get update
      #   apt-get install -y apache2
      # SHELL

    And replace them with:

      config.vm.provision "shell", inline: <<-SHELL
        yum install -C -y /vagrant/packages/postgresql*.rpm
        service postgresql-9.3 initdb
        service postgresql-9.3 start
        chkconfig postgresql-9.3 on
        sudo -i -u postgres createuser -d -e -E -I -r -s vagrant
        sudo -i -u vagrant createdb -e

    Save the changes.

  14. Destroy your vagrant environment.

    vagrant destroy
  15. Bring it up again and log in.
    vagrant up && vagrant ssh
  16. Run psql. You’re in.
    [vagrant@localhost ~]$ psql
    psql (9.3.15)
    Type "help" for help.
    vagrant=# \q
    [vagrant@localhost ~]$

Now you can play around, do whatever you like inside the Postgres instance, and just repeat the last three steps (destroy VM, bring it up, and start psql) as often as you need to. 🙂

Did these instructions help? Did you have any trouble? Any suggestions? Let me know in the comments.

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