Adding storage to an EBM

If your EBM handles many and/or large repos, you may need to move storage from the default location (in /opt/electricbook/git_cache on the same machine as your electricbook binary) to separate storage.

Quick overview

In short, you need to:

  1. Stop the electricbook service.
  2. Copy any existing repos to your new storage location.
  3. Change the git_cache value in your electricbook-[n].yml file to the path to your new storage location.
  4. Restart the electricbook service.

You’ll understand what these steps entail more clearly if you read the example below.

An example using Digital Ocean

This is a description of how you’d move repos on an EBM to Digital Ocean block storage.

1. Add a volume

This guide explains how to:

  1. Attach a new block-storage volume.
  2. Prepare the new volume.
  3. Test that the new volume is working.

(You might not even need the guide, because on Digital Ocean the process for adding a new volume is clearly explained as soon as you attach a new volume to your droplet from its ‘Volumes’ tab.)

Once your new volume is up and running, make a note of its location. For instance, by default your first storage volume in the London datacentre will be mounted at /mnt/volume-lon1-01.

2. Stop the electricbook

If you might have users working on the projects while you do this, let them know the EBM will be down for maintenance and then stop the electricbook service:

systemctl stop electricbook

3. Migrate existing repos

On your droplet, copy git_cache to your new volume. For instance, you might create an electricbook directory on it:

mkdir /mnt/volume-lon1-01/electricbook

and use rsync to copy everything to there:

rsync -avz /opt/electricbook/git_cache /mnt/volume-lon1-01/electricbook

Don’t delete the contents of your old /opt/electricbook/git_cache until you’re certain that the new storage location is working.

4. Update your EBM’s storage location config

In /opt/electricbook you will have created an electricbook-n.yml config file (where n is a number like 0 or 1). Let’s say yours is electricbook-0.yml.

Open electricbook-0.yml for editing (e.g. use nano electricbook-0.yml to edit it in the terminal), and change:

git_cache: "git_cache"


git_cache: "/mnt/volume-lon1-01/electricbook/git_cache"

Note: Don’t make config changes to electricbook.yml. This config file is checked into the template repo, and is the example config file. Your EBM’s config goes in electricbook-0.yml, which overrides any settings in electricbook.yml, and is ignored by git, so that settings, keys, etc. don’t get accidentally checked into version control. (The values in electricbook.yml are actually set from the ansible script on setup.)

5. Check or fix permissions

The git_cache directory needs to be owned by the electricbook user. If you didn’t create it this way, fix it from the command line:

sudo chown -R electricbook:electricbook [cache-directory]

where [cache-directory] is the directory you’ve configured as the cache. E.g.

sudo chown -R electricbook:electricbook /mnt/volume-lon1-01/electricbook/git_cache

6. Start the electricbook service

Restart the electricbook service:

systemctl start electricbook

7. Test that storage is working

One way to test is to use the EBM to create a new file in a project, and then check from the server terminal whether that file exists in the new storage location.

8. Delete the old git_cache

Only once you’re sure that the block storage is working should you delete the contents of your old git_cache directory (/opt/electricbook/git_cache by default):

rm -rf /opt/electricbook/git_cache/*