Podman Provisioner

Provisioner name: "podman"

The Vagrant Podman provisioner can automatically install Podman to be used as a drop in Docker replacement. This includes the ability to pull Docker containers, and configure certain containers to run on boot. The podman provisioner is ideal for organizations that are using Podman as a means to manage and run their OCI images.

As with all provisioners, the Podman provisioner can be used along with all the other provisioners Vagrant has in order to setup your working environment the best way possible. For example, perhaps you use Puppet to install services like databases or web servers but use Podman to house your application runtime. You can use the Puppet provisioner along with the Podman provisioner.

Note, that in order to install Podman on RHEL systems, the system must be registered.

Options

The podman provisioner takes various options. None are required. If no options are provided, the Podman provisioner will only install Podman for you (if it is not already installed).

images (array) - A list of images to pull using podman pull. You can also use the pull_images function. See the example below this section for more information.

In addition to the options that can be set, various functions are available and can be called to configure other aspects of the Podman provisioner. Most of these functions have examples in more detailed sections below.

build_image - Build an image from a Dockerfile.
kubic - Boolean, install Podman from Kubic project
pull_images - Pull the given images. This does not start these images.
post_install_provisioner - A provisioner block that runs post podman installation.
run - Run a container and configure it to start on boot. This can only be specified once.

Building Images

The provisioner can automatically build images. Images are built prior to any configured containers to run, so you can build an image before running it. Building an image is easy:

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provision "podman" do |d|
    d.build_image "/vagrant/app"
  end
end

The argument to build an image is the path to give to podman build. This must be a path that exists within the guest machine. If you need to get data to the guest machine, use a synced folder.

The build_image function accepts options as a second parameter. Here are the available options:

args (string) - Additional arguments to pass to podman build. Use this to pass in things like -t "foo" to tag the image.

Pulling Images

The podman provisioner can automatically pull images from the Docker registry for you. There are two ways to specify images to pull. The first is as an array using images:

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provision "podman",
    images: ["ubuntu"]
end

This will cause Vagrant to pull the "ubuntu" image from the registry for you automatically.

The second way to pull images is to use the pull_images function. Each call to pull_images will append the images to be pulled. The images variable, on the other hand, can only be used once.

Additionally, the pull_images function cannot be used with the simple configuration method for provisioners (specifying it all in one line).

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provision "podman" do |d|
    d.pull_images "ubuntu"
    d.pull_images "vagrant"
  end
end

Running Containers

In addition to pulling images, the Podman provisioner can run and start containers for you. This lets you automatically start services as part of vagrant up.

Running containers can only be configured using the Ruby block syntax with the do...end blocks. An example of running a container is shown below:

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provision "podman" do |d|
    d.run "rabbitmq"
  end
end

This will podman run a container with the "rabbitmq" image. Note that Vagrant uses the first parameter (the image name by default) to override any settings used in a previous run definition. Therefore, if you need to run multiple containers from the same image then you must specify the image option (documented below) with a unique name.

In addition to the name, the run method accepts a set of options, all optional:

image (string) - The image to run. This defaults to the first argument but can also be given here as an option.
cmd (string) - The command to start within the container. If not specified, then the container's default command will be used, such as the "CMD" command specified in the Dockerfile.
args (string) - Extra arguments for podman run (same as the extra arguments that can be specified for docker run) on the command line. These are raw arguments that are passed directly to Podman.
auto_assign_name (boolean) - If true, the --name of the container will be set to the first argument of the run. By default this is true. If the name set contains a "/" (because of the image name), it will be replaced with "-". Therefore, if you do d.run "foo/bar", then the name of the container will be "foo-bar".
daemonize (boolean) - If true, the "-d" flag is given to podman run to daemonize the containers. By default this is true.
restart (string) - The restart policy for the container. Defaults to "always"

For example, here is how you would configure Podman to run a container with the Vagrant shared directory mounted inside of it:

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provision "podman" do |d|
    d.run "ubuntu",
      cmd: "bash -l",
      args: "-v '/vagrant:/var/www'"
  end
end

In case you need to run multiple containers based off the same image, you can do so by providing different names and specifying the image parameter to it:

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.provision "podman" do |d|
    d.run "db-1", image: "user/mysql"
    d.run "db-2", image: "user/mysql"
  end
end