Experiment Development Containers (XDCs)
AttentionThis guide assumes you are using the reference portal at
redstartb.net. If you are using a different portal, substitute addresses in this document that reference
redstartb.netaccordingly. Consult your project leader if you are not sure of the portal address.
Users interact with materialized experiments through experiment development containers (XDC).
Users can create XDCs and attach them to materialized experiments through either the
mrg CLI or
the web GUI, and can connect to XDCs from their workstations using either a Jupyter web interface or
through a standard SSH command line client. Users commonly use XDCs as a single, centralized point
of command and control for experiment automation and orchestration.
This walkthrough will show the process of creating an XDC, attaching it to a materialization, and connecting to it through a standard SSH configuration.
At a high level an XDC provides a typical Linux environment through which the user can connect to and thus control their materialization nodes over a secure network. XDCs run on the Merge portal and act as an intermediary between your workstation and the nodes of an experiment materialization.
The following summarizes the basic characteristics of the Merge XDC:
- Any user can create an XDC either via the web GUI or
- Each XDC is associated with a single project. That project may be a user’s personal project, or it may be a project with multiple additional members.
- Each XDC runs in an environment that is accessible to each member of the project. Each project member has access to the XDC, even if they did not create the XDC themselves.
- Each XDC runs an Ubuntu 20.04 container with standard Ubuntu tools and binaries.
- XDCs are accessible both online via a Jupyter web interface and via SSH.
- XDC have remote permanent storage mounted so data remains after an XDC is destroyed.
/home/$USER- All home directories of project members
/project- A shared project directory that all project members can access
Creating an XDC via the CLI
First, create an XDC with
mrg new xdc x0.murphy
This creates a new XDC
x0 associated with the personal project of the user
Attaching an XDC to a materialization
Assume the user has a materialization named
world.hello.murphy. We now attach the XDC
to this materialization
mrg xdc attach x0.murphy world.hello.murphy
TipRemember that XDCs are created in the context of a specific project (which could be a user’s personal project). An XDC created in the namespace of one project cannot be attached to a materialization in a different project, even if the user is a member of both projects.
Reaching an XDC via SSH
First, add the SSH jump host to the SSH configuration for your account on your local workstation,
~/.ssh/config on typical installations) filling in
<username> with your MergeTB username and
Hostname based on the address of your portal:
Host mergejump Hostname jump.redstartb.net Port 2022 User <username> IdentityFile ~/.ssh/merge_key ServerAliveInterval 30
TipThe identity file
~/.ssh/merge_keyis populated automatically after you successfully login via the CLI (
mrg login <username>) on your local workstation
Now, use SSH to reach your XDC, using the
-J option to specify the name of the jump host:
# ssh -i ~/.ssh/merge_key -J <jumphost> <username>@<xdc>-<project> ssh -i ~/.ssh/merge_key -J mergejump murphy@x0-murphy
AttentionThe hostname used to reach your XDC via SSH is dash delimited (e.g.,
x0-murphy) rather than dot delimited (
Detaching an XDC from a materialization
Assume now the user wants to attach
x0 to a new materialization named
planet.hello.murphy. We must
detach from the first materialization before attaching to the second:
mrg xdc detach x0.murphy mrg xdc attach x0.murphy planet.hello.murphy