Easy VM (ezvm)

This app makes it easy for you to update and manage your VMs without having to recreate them or manually update your stuff.

Ideal for working in teams when the state of your VM is changing, software is being added, removed, updated and you don't want people to have to do anything other than type ezvm update to get the latest changes applied to their work-in-progress.

Generally speaking if you have items that just need to be installed once when your VM is created, you're better off putting those things in a Chef recipe and using vagrant provision for rare updates of the VM.

However when you're actively modifying the state of a VM to add/remove things, ezvm can be much easier to play around with and share your changes with others.

Installation

$ git clone https://github.com/vube/ezvm
$ sudo mv ezvm /usr/local/

Then either add /usr/local/ezvm/bin to your path like

$ export PATH="$PATH:/usr/local/ezvm/bin"

OR you can symlink ezvm from /usr/local/bin assuming that is already in your path, like:

$ ln -sf /usr/local/ezvm/bin/ezvm /usr/local/bin/ezvm

Usage

After you configure ezvm, you can use it thusly:

$ ezvm update

The above will update your VM.

$ ezvm selfupdate

The above will update ezvm itself to the latest release.

$ ezvm exec get-update-list

The above command will print a list of all of the local updates that will be applied when you run ezvm update

These commands aren't actually executed during this command, they are just printed for your reference.

Output Verbosity

Output verbosity is set via the EZVM_VERBOSITY environment variable. By default it = 1.

EZVM_VERBOSITY can be set from any value from 1-100

The meanings are as follows:

Level  Description
-----  --------------------------------
   1   Notice - Default verbosity level
  10   Info
  50+  Debug
  80+  Trace (LOTS of output)

Configuration

etc/local Directory

The etc/local directory is the "Local Content Directory". Generally speaking, this is where you should store your own files.

After you install ezvm you should then copy over the contents of etc/local from your own repository, and then ezvm is ready to run.

The etc/local directory is excluded from Git, you must manage this directory.

etc/local/update Directory

etc/local/update is where you should put all of your update routines. You should put shell scripts here that will be executed in sorted order.

The special file extension .ROOT (dot ROOT) tells ezvm to run this script as the root user. If the file extension is not .ROOT then it will run with ordinary user permissions.

See the test/fixtures/update directory for a sample of the kinds of things you could put in etc/local/update

TODO: Tip for Local Content self-update-hook

TODO: Write an example self-update-hook that will git pull the etc/local contents from whatever repository you store it at. Thus every time you ezvm update you'll have all the latest copies of your own configs and scripts before updating.

etc/local/home Directory

This directory is totally optional.

IF this directory exists, then the first time ezvm update is run on a machine (and only the first time) the contents of this directory will be copied to your home directory.

If you have multiple users who want their own files, each user should make a directory named etc/local/home/{username} where {username} is their username. If their own directory exists, its contents will be copied ON TOP of the generic home contents.

If you cannot have specific usernames when you execute ezvm, you can optionally set the EZVM_USERNAME environment variable to emulate running as that user, and that user's home directory will be copied.

Advanced Usage

ezvm exec

This is useful for testing your local update procedures.

ezvm exec get-update-list

$ ezvm exec get-update-list

The above command will print a list of all of the local updates that will be applied when you run ezvm update

These commands aren't actually executed during this command, they are just printed for your reference.

ezvm exec <update_script>

$ ezvm exec 010-update-script.sh

The above example will run the script 010-update-script.sh from your local update directory, by default $EZVM_BASE_DIR/etc/local/update

Testing

The test procedures here are pretty simple, they execute ezvm and you essentially have to verify that it's working manually. Old school!

test/unit.sh

This script will execute the unit tests. It executes all test/tests/*.test scripts unless/until one of them experiences an error. It exits cleanly if all tests pass.

test/exec.sh

This allows you to run just single update fixture, same as ezvm exec

$ test/exec.sh 003-copy-home-dir

The example above just runs the test/fixtures/update/003-copy-home-dir update procedure. Change it up to run any specific one you want to test in more detail.

$ test/exec.sh -V 100 003-copy-home-dir

Use -V 100 to enable a huge amount of debugging output, helpful if you are trying to figure out why your script isn't working as expected.

test/end2end.sh

This script executes all of the test update fixtures as if you ran ezvm update

If everything works correctly it exits cleanly.