# Host undetermined in Batch Connect, noVNC

**URL:** <https://discourse.openondemand.org/t/host-undetermined-in-batch-connect-novnc/2359>\
**Category:** Get Help\
**Tags:** ondemand2, question\
**Created:** [November 7, 2022, 3:12pm UTC](https://discourse.openondemand.org/t/host-undetermined-in-batch-connect-novnc/2359 "2022-11-07T15:12:51Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![ikirker](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/ikirker/32/705_2.png) [@ikirker](https://discourse.openondemand.org/u/ikirker)\
**Post date:** [November 7, 2022, 3:12pm UTC](https://discourse.openondemand.org/t/host-undetermined-in-batch-connect-novnc/2359/1 "2022-11-07T15:12:51Z")

</div>

I’m setting up Open OnDemand 2.0.28-1 for the first time on one of our RHEL 7 clusters, with an SGE 8.1.9 scheduler.

I’ve got most of it working so far, but here’s the problem I’m having:

- in the Batch Connect interface, I can launch a job, no problem, it queues and runs,
- when it starts running, it shows “ **Host:** Undetermined”,
- if I try to launch the noVNC desktop, it fails to connect, because the websocket URL does not contain the hostname, so e.g. the websocket URL looks like `wss://ood.ext.myriad.ucl.ac.uk/rnode//1343/websockify`,
- finding out which node the job is running on and writing it into the noVNC URL successfully connects and gives me a desktop.

I’m not sure where to go looking for how this hostname should be determined: inferring from an older thread, I tried adding a `set_host` key to my cluster definition:

```auto
  batch_connect:
      # This may need some tweaking to get right
      # See: https://osc.github.io/ood-documentation/master/installation/cluster-config-schema.html#batch-connect
      basic:
        script_wrapper: "%s"
        set_host: "host=$(hostname -a)"
      vnc:
        script_wrapper: "singularity exec -B /shared,/lustre,/run /shared/ucl/apps/siflib/centos-8s-quay.sif %s"
        set_host: "host=$(hostname -a)"

```

And also in this `/etc/ood/config/apps/bc_desktop/submit/container.yml.erb` setup I adapted from this thread: [Mate Desktop in a Singularity container? - #40 by novosirj](https://discourse.openondemand.org/t/mate-desktop-in-a-singularity-container/696/40)

```auto
---
script:
  # customised, not sure about this yet
  # the SGE adapter setup for this seems different to others?
  # nodes: "<%= bc_num_slots %><%= node_type %>"
  native:
     - -pe
     - smp
     - <%= num_cores.blank? ? 1 : num_cores.to_i %>
     - -l
     - mem=<%= memory_gigs %>G
     - -l
     - tmpfs=<%= tmpfs_gigs %>G
  template: "vnc"
batch_connect:
  websockify_cmd: '/usr/bin/websockify'
  header: |
    #!/bin/bash -l
    source ~/.bashrc
  set_host: "host=$(hostname -a)"
  script_wrapper: |
    set -x
    module purge
    module load singularity-env
    cat << "CTRSCRIPT" > container.sh
    export PATH="$PATH:/opt/TurboVNC/bin"
    %s
    CTRSCRIPT

    # customised
    export SINGULARITY_BINDPATH="$HOME,/lustre,/scratch,/shared,/var,/run,/tmp,/tmpdir"

    singularity run <%= image %> /bin/bash container.sh

```

And here’s the corresponding `form.yml.erb`:

```auto
title: "Myriad Desktop"
cluster: "myriad"
submit: submit/container.yml.erb
attributes:
  desktop: "mate"
  bc_vnc_idle: 0
  bc_vnc_resolution:
    required: true
  node_type: null

  memory_gigs:
    widget: "number_field"
    label: "Gigabytes of memory"
    value: 4
  tmpfs_gigs:
    widget: "number_field"
    label: "Gigabytes of temporary on-node storage"
    value: 10

form:
  - bc_vnc_idle
  - desktop
  - bc_account
  - bc_num_hours
  - bc_num_slots
  - num_cores
  - memory_gigs
  - tmpfs_gigs
  - node_type
  - bc_queue
  - bc_vnc_resolution
  - bc_email_on_started

```

But setting that `set_host` field didn’t seem to change anything. As far as I can tell, the original definition of that is just `hostname` anyway, from: `/opt/ood/ondemand/root/usr/share/gems/2.7/ondemand/2.0.28/gems/ood_core-0.21.0/lib/ood_core/batch_connect/template.rb` ?

Any pointers would be appreciated: I’m guessing this would ideally be set somewhere in the SGE adapter, maybe as an `exec_host` field to a job object somewhere, but I’m not entirely sure.

---

<div class="post-metadata">

**Author:** ![gbyrket](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/gbyrket/32/894_2.png) [@gbyrket](https://discourse.openondemand.org/u/gbyrket)\
**Post date:** [November 7, 2022, 5:39pm UTC](https://discourse.openondemand.org/t/host-undetermined-in-batch-connect-novnc/2359/2 "2022-11-07T17:39:30Z")

</div>

Hi Ian.

Thanks for your post.

I will see what I can find out for you.

Thanks,  
-gerald

---

<div class="post-metadata">

**Author:** ![ikirker](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/ikirker/32/705_2.png) [@ikirker](https://discourse.openondemand.org/u/ikirker)\
**Post date:** [November 10, 2022, 4:48pm UTC](https://discourse.openondemand.org/t/host-undetermined-in-batch-connect-novnc/2359/3 "2022-11-10T16:48:49Z")

</div>

Some trawling back through from the “Undetermined” string in the i18n files to the `session.rb` file in the `batch_connect` classes pointed me in the direction of generated `connection.yml` files.

Looking at those files for jobs I’ve submitted has shown that they have an empty host field, and if I fix the file manually, the noVNC sessions work from the web interface.

So I worked out how those files are generated… and it turned out:

- `hostname -a` returns a blank string on our cluster nodes
- `hostname` wasn’t even installed in the Singularity image (thanks, default Centos 8 Stream image)

I’ve changed the `set_host` fields to `host=$(hostname -s)` everywhere, and added `hostname` to the Singularity image, and now getting the host seems to be working and the noVNC sessions start without any manual steps.

👍

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex015/uploads/osc/original/2X/b/bae70bd0ed39a3ae769c2108155f4cb3e9da8385.png) [@system](https://discourse.openondemand.org/u/system)\
**Post date:** [May 9, 2023, 4:49pm UTC](https://discourse.openondemand.org/t/host-undetermined-in-batch-connect-novnc/2359/4 "2023-05-09T16:49:04Z")

</div>

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.