vagrant-haskell: haskell in a box

vagrant-haskell is a vagrant box shipping a minimal haskell toolchain via darinmorrison/docker-haskell.

Contents

The default configuration of vagrant-haskell provides the following:

package	version
alex	3.1.3
cabal-install	1.20.0.3
happy	1.19.4
ghc	7.8.3

Why Vagrant?

vagrant provides a more convenient interface for interacting with docker-haskell as a portable Haskell development environment than using docker or boot2docker directly.

• A familiar VM-style workflow

  ~/vagrant-haskell/container ❯❯❯ vagrant up --provider=docker    # initialize vm, download image, launch container
  

• Convenient SSH access

  ~/vagrant-haskell/container ❯❯❯ vagrant ssh
  ==> default: SSH will be proxied through the Docker virtual machine since we're
  ==> default: not running Docker natively. This is just a notice, and not an error.
  Warning: Permanently added '172.17.0.2' (ECDSA) to the list of known hosts.
  Last login: Sat May 31 00:01:06 2014 from 172.17.42.1
  root@219d34de7386:~# exit
  logout
  Connection to 172.17.0.2 closed.
  Connection to 127.0.0.1 closed.
  ~/vagrant-haskell/container ❯❯❯
  

• NFS-based shared folders

  ~/vagrant-haskell/container ❯❯❯ echo 'main = print "hello, docker and vagrant!"' > shared/Main.hs
  ~/vagrant-haskell/container ❯❯❯ vagrant ssh
  [...]
  root@219d34de7386:~# cd shared && ghc --make Main && ./Main
  [1 of 1] Compiling Main             ( Main.hs, Main.o )
  Linking Main ...
  "hello, docker and vagrant!"
  

How do I use this?

1. install virtualbox

2. install vagrant

3. check out the repository:

   ~ ❯❯❯ git clone https://github.com/darinmorrison/vagrant-haskell
   

4. start vagrant (optionally overriding cpu/mem resources):

   ~ ❯❯❯ cd vagrant-haskell/container && vagrant up --provider=docker
   

   • After a few moments the images are downloaded and the VM initialized

Halting Vagrant

When using the docker provider, Vagrant controls the container separately from the host. Normally, the host is kept running so that multiple containers can be started quickly without spinning up a new VM.

If you want to halt the host along with the container you need to do so explicitly.

The following session illustrates how to accomplish this:

~/vagrant-haskell ❯❯❯ vagrant global-status
id       name    provider   state   directory
-----------------------------------------------------------------------------------------------
3dca2c4  default docker     running ~/vagrant-haskell/container
f28aefd  default virtualbox running ~/vagrant-haskell/host

The above shows information about all known Vagrant environments
on this machine. This data is cached and may not be completely
up-to-date. To interact with any of the machines, you can go to
that directory and run Vagrant, or you can use the ID directly
with Vagrant commands from any directory. For example:
"vagrant destroy 1a2b3c4d"

~/vagrant-haskell ❯❯❯ echo container host | xargs -n1 -I {} bash -c 'cd {} && vagrant halt && vagrant status'
==> default: Stopping container...
Current machine states:

default                   stopped (docker)

The container is created but not running. You can run it again
with `vagrant up`. If the container always goes to "stopped"
right away after being started, it is because the command being
run exits and doesn't keep running.
==> default: Attempting graceful shutdown of VM...
Current machine states:

default                   poweroff (virtualbox)

The VM is powered off. To restart the VM, simply run `vagrant up`

~/vagrant-haskell ❯❯❯ vagrant global-status
id       name    provider   state    directory
------------------------------------------------------------------------------------------------
3dca2c4  default docker     stopped  ~/vagrant-haskell/container
f28aefd  default virtualbox poweroff ~/vagrant-haskell/host

The above shows information about all known Vagrant environments
on this machine. This data is cached and may not be completely
up-to-date. To interact with any of the machines, you can go to
that directory and run Vagrant, or you can use the ID directly
with Vagrant commands from any directory. For example:
"vagrant destroy 1a2b3c4d"

Customizing the Environment

Some parameters can be modified by setting environment variables:

environment variable	default value	purpose
VAGRANT_B2D_CPUS	total # of logical cores	number of cores to allocate to vagrant
VAGRANT_B2D_CPU_CAP	85 (out of 100)	max percentage of cpu capacity to allocate per core
VAGRANT_B2D_GUI	false	controls whether docker host VM is run headless or not
VAGRANT_B2D_RAM	1/4th total (MB)	memory to allocate to vagrant
VAGRANT_B2D_SHARE_NAME	shared	name of shared folder
VAGRANT_B2D_SHARE_ROOT	.	parent of shared folder relative to vagrant-haskell/container

Example:

~/vagrant-haskell/container ❯❯❯ VAGRANT_B2D_CPUS='8' VAGRANT_B2D_RAM='8192' vagrant up --provider=docker