Debugging Charmed OSM

This document aims to provide the OSM community an easy way of testing and debugging OSM.

Benefits:

Use upstream published images for debugging: No need to build local images anymore.
Easily configure modules for debugging_mode: juju config <module> debug_mode=True debug_pubkey="ssh-rsa ...".
Debug in K8s: All pods (the debugged ones and the rest) will be running always in K8s.
Seemless setup: VSCode will connect through SSH to the pods.
Keep your changes save: Possibility to mount local module to the container; all the changes will be saved automatically to your local filesystem.

Install OSM

Download the installer:

wget http://osm-download.etsi.org/ftp/osm-10.0-ten/install_osm.sh
chmod +x install_osm.sh

Install OSM from master (tag=testing-daily):

./install_osm.sh -R testing-daily -r testing --charmed

Install OSM from a specific tag:

./install_osm.sh -R testing-daily -r testing --charmed --tag <X.Y.Z>

Debugging

Once the Charmed OSM installation has finished, you can select which applications you want to run with the debug mode.

# LCM
juju config lcm debug_mode=True  debug_pubkey="`cat ~/.ssh/id_rsa.pub`"
# MON
juju config mon debug_mode=True  debug_pubkey="`cat ~/.ssh/id_rsa.pub`"
# NBI
juju config nbi debug_mode=True  debug_pubkey="`cat ~/.ssh/id_rsa.pub`"
# RO
juju config ro debug_mode=True  debug_pubkey="`cat ~/.ssh/id_rsa.pub`"
# POL
juju config pol debug_mode=True  debug_pubkey="`cat ~/.ssh/id_rsa.pub`"

Enabling the debug_mode will put a sleep infinity as the entrypoint of the container. That way, we can later connect to the pod through SSH in VSCode, and run the entrypoint of the application from the debugger.

Mounting local modules

The Charmed OSM Debugging mode allows you to mount local modules to the desired charms. The following commands show which modules can be mounted in each charm.

LCM_LOCAL_PATH="/path/to/LCM"
N2VC_LOCAL_PATH="/path/to/N2VC"
NBI_LOCAL_PATH="/path/to/NBI"
RO_LOCAL_PATH="/path/to/RO"
MON_LOCAL_PATH="/path/to/MON"
POL_LOCAL_PATH="/path/to/POL"
COMMON_LOCAL_PATH="/path/to/common"

# LCM
juju config lcm debug_lcm_local_path=$LCM_LOCAL_PATH
juju config lcm debug_n2vc_local_path=$N2VC_LOCAL_PATH
juju config lcm debug_common_local_path=$COMMON_LOCAL_PATH
# MON
juju config mon debug_mon_local_path=$MON_LOCAL_PATH
juju config mon debug_n2vc_local_path=$N2VC_LOCAL_PATH
juju config mon debug_common_local_path=$COMMON_LOCAL_PATH
# NBI
juju config nbi debug_nbi_local_path=$LCM_LOCAL_PATH
juju config nbi debug_common_local_path=$COMMON_LOCAL_PATH
# RO
juju config ro debug_ro_local_path=$RO_LOCAL_PATH
juju config ro debug_common_local_path=$COMMON_LOCAL_PATH
# POL
juju config pol debug_pol_local_path=$POL_LOCAL_PATH
juju config pol debug_common_local_path=$COMMON_LOCAL_PATH

Generate SSH config file

Preparing the pods includes setting up the ~/.ssh/config so the VSCode can easily discover which ssh hosts are available

Just execute:

./generate_ssh_config.sh

NOTE: The public key that will be used will be $HOME/.ssh/id_rsa.pub. If you want to use a different one, add the absolute path to it as a first argument: ./generate_ssh_config.sh /path/to/key.pub.

Connect to Pods

In VScode, navigate to Remote Explorer, and select the pod to which you want to connect.

You should be able to see the following hosts in the Remote Explorer:

Right click on the host, and "Connect to host in a New Window".

Add workspace

The ./generate_ssh_config.sh script adds a workspace to the /root folder of each pod, with the following name: debug.code-workspace.

In the window of the connected host, go to File/Open Workspace from File.... Then select the debug.code-workspace file.

Run and Debug

Open the Terminal tab, and the Python extension will be automatically downloaded. It will be installed in the remote pod.

Go to the Explorer (ctrl + shift + E) to see the module folders in the charm. You can add breakpoints and start debugging.

Go to the Run and Debug (ctrl + shift + D) and press F5 to start the main entrypoint of the charm.

Happy debugging!