action-get fails with "exit status 1"

[dreibh]

Trying to get the value of a parameter with action_get() fails with an exception, since the call to the program action-get fails with exit code 1. However, there is no information about what went wrong with the call: subprocess.CalledProcessError: Command '['action-get', 'cassandra-server-ip', '--format=json']' returned non-zero exit status 1

Is there any possibility to get some information about what is going wrong with "action-get"?

My Charm:

action.yaml:
...
configure-hss:
description: Configures the HSS
params:
cassandra-server-ip:
description: Cassandra Server IP
data-type: string
default: 172.16.6.129
required:
- cassandra-server-ip
...

The code:
...
@when('actions.configure-cassandra')
...
def configure_cassandra():
cassandraServerIP = action_get('cassandra-server-ip')
...

VNF:
...
# ====== Juju Charm ===============================================
vdu-configuration:
juju:
charm: hsscharm
initial-config-primitive:
- seq: '1'
name: config
parameter:
- name: ssh-hostname
value: <rw_mgmt_ip>
- name: ssh-username
value: nornetpp
- name: ssh-password
value:
- seq: '2'
name: prepare-cassandra-hss-build
parameter:
- name: hss-git-repository
value: https://github.com/OPENAIRINTERFACE/openair-cn-cups.git
- name: hss-git-commit
value: develop
- seq: '3'
name: configure-cassandra
parameter:
- name: cassandra-server-ip
value: 172.16.6.129
...

Juju log:
2019-11-18 10:26:06 DEBUG update-status Traceback (most recent call last):
2019-11-18 10:26:06 DEBUG update-status File "/var/lib/juju/agents/unit-simulamet-oai-epc-b-hss-aa-0/charm/hooks/update-status", line 22, in
2019-11-18 10:26:06 DEBUG update-status main()
2019-11-18 10:26:06 DEBUG update-status File "/usr/local/lib/python3.5/dist-packages/charms/reactive/init.py", line 74, in main
2019-11-18 10:26:06 DEBUG update-status bus.dispatch(restricted=restricted_mode)
2019-11-18 10:26:06 DEBUG update-status File "/usr/local/lib/python3.5/dist-packages/charms/reactive/bus.py", line 390, in dispatch
2019-11-18 10:26:06 DEBUG update-status _invoke(other_handlers)
2019-11-18 10:26:06 DEBUG update-status File "/usr/local/lib/python3.5/dist-packages/charms/reactive/bus.py", line 359, in _invoke
2019-11-18 10:26:06 DEBUG update-status handler.invoke()
2019-11-18 10:26:06 DEBUG update-status File "/usr/local/lib/python3.5/dist-packages/charms/reactive/bus.py", line 181, in invoke
2019-11-18 10:26:06 DEBUG update-status self._action(*args)
2019-11-18 10:26:06 DEBUG update-status File "/var/lib/juju/agents/unit-simulamet-oai-epc-b-hss-aa-0/charm/reactive/hsscharm.py", line 197, in configure_cassandra
2019-11-18 10:26:06 DEBUG update-status cassandraServerIP = action_get('cassandra-server-ip')
2019-11-18 10:26:06 DEBUG update-status File "/usr/local/lib/python3.5/dist-packages/charmhelpers/core/hookenv.py", line 82, in wrapper
2019-11-18 10:26:06 DEBUG update-status res = func(*args, **kwargs)
2019-11-18 10:26:06 DEBUG update-status File "/usr/local/lib/python3.5/dist-packages/charmhelpers/core/hookenv.py", line 974, in action_get
2019-11-18 10:26:06 DEBUG update-status action_data = json.loads(subprocess.check_output(cmd).decode('UTF-8'))
2019-11-18 10:26:06 DEBUG update-status File "/usr/lib/python3.5/subprocess.py", line 626, in check_output
2019-11-18 10:26:06 DEBUG update-status **kwargs).stdout
2019-11-18 10:26:06 DEBUG update-status File "/usr/lib/python3.5/subprocess.py", line 708, in run
2019-11-18 10:26:06 DEBUG update-status output=stdout, stderr=stderr)
2019-11-18 10:26:06 DEBUG update-status subprocess.CalledProcessError: Command '['action-get', 'cassandra-server-ip', '--format=json']' returned non-zero exit status 1
2019-11-18 10:26:06 ERROR juju.worker.uniter.operation runhook.go:113 hook "update-status" failed: exit status 1

The issue appears in 100% of the cases, i.e. I can reliably reproduce it. Also, trying to manually invoke the funtion (i.e.: juju run-action simulamet-oai-epc-b-hss-aa/0 configure-cassandra cassandra-server-ip=1.2.3.4) leads to the same issue.

Note, that my VNF applies the Juju charm as part of the VDU configuration. I am not sure whether this is important for the issue.

[dreibh]

I noticed probably the same failure in another part of my charm, this time with "action-fail" returning status 1. That is, probably the issue is not the handling of parameters but some problem with the state of the Juju instance?

[dreibh]

The container for controlling the VDU seems to use juju version 2.3.7, i.e. action-get is /var/lib/juju/tools/2.3.7-xenial-amd64/action-get . Could the Juju version in the container be the problem? I am using an OSM Release SIX setup.

[dreibh]

When checking the contents of the Juju container for the VDU, I noticed the following:

• The APT packages are up-to-date, i.e. "apt dist-upgrade" does not find anything to upgrade.
• "pip list --outdated --format=freeze" however shows a list of packages which are not up-to-date.

So, I tried to update the Python packages:
apt install -y pkg-config libcurl4-openssl-dev libcairo2-dev libssl-dev libgirepository1.0-dev
pip list --outdated --format=freeze | grep -v '^-e' | cut -d = -f 1 | xargs -n1 pip install -U

This leaves 4 packages are installed by apt-get, which pip cannot upgrade:

pip list --outdated

Package Version Latest Type

---

blinker 1.3 1.4 sdist
pycurl 7.43.0 7.43.0.3 sdist
pygobject 3.20.0 3.34.0 sdist
pyserial 3.0.1 3.4 wheel

So, may be the Python installation inside the container needs a look whether there is some incompatibility between "apt-get"-installed and "pip"-installed packages?

However, this does not solve my issue with "action-get". After upgrading the packages, I tried to run my configuration commands again => same problem.

[AdamIsrael]

Would you be willing to share the charm layer you've written with me? It'll be easier to debug if I can look at your code as a whole. If so, you can email it to me at adam.israel@canonical.com. I'm currently at the OSM F2F/Hackfest #8 but I'll take a look as soon as I can.