2. Install Desktop App¶

Now we will install the provided bc_desktop app as well as configure it work at your center.

We will build this app in our previous web applications setup directory (discussed in Install Applications):
```
cd ~/ood/src/apps/
```
By default this app is not built and installed with all the other required OOD apps. You will need to build this app explicitly with:
```
scl enable rh-ruby22 nodejs010 git19 -- rake build:bc_desktop
```
Note

The Desktop App is an optional app and will not be built and installed when you call:
```
scl enable rh-ruby22 nodejs010 git19 -- rake
sudo scl enable rh-ruby22 -- rake install
```
Instead you need to explicitly build and install it to prevent you from installing an app that is not properly configured for your users:
```
scl enable rh-ruby22 nodejs010 git19 -- rake build:bc_desktop
sudo scl enable rh-ruby22 -- rake install:bc_desktop
```

We now must configure Desktop apps for each cluster you want this to run under in the following directory build/bc_desktop/local/

# Make the `local/` directory if it doesn't already exist
mkdir build/bc_desktop/local

# Change our working directory to `local/`
cd build/bc_desktop/local

For each cluster we want to launch a Desktop session on we will need a corresponding form configuration file in YAML format (e.g., cluster1.yml, cluster2.yml, …) that looks like:
```
# bc_desktop/local/cluster1.yml
---
title: "Cluster1 Desktop"
cluster: "cluster1"        # must correspond to a cluster config
```
where the cluster attribute must match a valid cluster configuration file.

Danger

Please do not modify any of the code underneath the bc_desktop/ path other than in bc_desktop/local/ as it may put the Git repo in a bad state.

We recommend you version all the changes you make in the bc_desktop/local/ directory you use for the bc_desktop app so that you don’t lose any of your modifications.

Install the Desktop App to its system location at /var/www/ood/apps/sys with:

# Go back into the apps root directory
cd ~/ood/src/apps/

# Install the `bc_desktop` app to its system location
sudo scl enable rh-ruby22 -- rake install:bc_desktop

Navigate to your OnDemand site, in particular the Dashboard App, and you should see in the top dropdown menu “Interactive Apps” => “Cluster1 Desktop”.

After choosing “Cluster1 Desktop” from the menu, you should be presented with a form to submit a Desktop session to the given cluster.

Submit a Desktop session and wait for it to run. If you see a Desktop session start Running but then quickly disappear you can debug it by viewing the logs in:
```
~/ondemand/data/sys/dashboard/batch_connect/sys/bc_desktop/<cluster>/output/<uuid>/
```
where uuid is a randomly generated id for a single Desktop session. You might want to find the latest one by looking at the timestamps.

Warning

The form may fail to submit due to the defaults we chose for a given resource manager: Torque, Slurm, LSF, PBS Pro… Please continue to the next section to learn how to customize batch job submission.