k8s spec must expose ports or fails with no error

[Hamish]

Developing charms with the operator framework, and juju v2.7.1

Issue:

If you don't expose ports on the container in a k8s spec then there is no error and the pod doesn't get created.

Expected:

Error if the pod won't get created.

Ideal:

Allow for containers to be created with no exposed ports

Test steps:

Without ports:

 - Charm sets spec like below.

self.framework.model.pod.set_spec({
    'containers': [{
        'name': 'no-ports-test',
        'imageDetails': {
            'imagePath': 'busybox'
        },
        'command': ['sh', '-c'],
        'args': ['while(sleep 2); do date; done'],
        'imagePullPolicy': 'IfNotPresent',
    }]
})

 - I see logs like

$ kubectl -n test-k8s logs --tail=100 -f no-ports-test-operator-0
2020-01-29 02:01:38 INFO juju-log handle_event: StartEvent
2020-01-29 02:01:39 DEBUG start Pod.set_spec {"containers": [{"name": "no-ports-test", "imageDetails": {"imagePath": "busybox"}, "command": ["sh", "-c"], "args": ["while(sleep 2); do date; done"], "imagePullPolicy": "IfNotPresent"}]}
2020-01-29 02:01:40 INFO juju-log handle_event: LeaderElectedEvent
2020-01-29 02:01:40 DEBUG leader-elected Pod.set_spec {"containers": [{"name": "no-ports-test", "imageDetails": {"imagePath": "busybox"}, "command": ["sh", "-c"], "args": ["while(sleep 2); do date; done"], "imagePullPolicy": "IfNotPresent"}]}
2020-01-29 02:01:41 INFO juju-log handle_event: ConfigChangedEvent
2020-01-29 02:01:42 DEBUG config-changed Pod.set_spec {"containers": [{"name": "no-ports-test", "imageDetails": {"imagePath": "busybox"}, "command": ["sh", "-c"], "args": ["while(sleep 2); do date; done"], "imagePullPolicy": "IfNotPresent"}]}

No more logs and the pod doesn't get created.

With ports:

 - Charm sets spec like below.

self.framework.model.pod.set_spec({
    'containers': [{
        'name': 'no-ports-test',
        'imageDetails': {
            'imagePath': 'busybox'
        },
        'command': ['sh', '-c'],
        'args': ['while(sleep 2); do date; done'],
        'imagePullPolicy': 'IfNotPresent',
        'ports': [{
            'containerPort': 80,
            'protocol': 'TCP',
        }],
    }]
})

 - I see logs like

$ kubectl -n test-k8s logs --tail=100 -f no-ports-test-operator-0
2020-01-29 02:08:10 INFO juju-log handle_event: StartEvent
2020-01-29 02:08:10 DEBUG start Pod.set_spec {"containers": [{"name": "no-ports-test", "imageDetails": {"imagePath": "busybox"}, "command": ["sh", "-c"], "args": ["while(sleep 2); do date; done"], "imagePullPolicy": "IfNotPresent", "ports": [{"containerPort": 80, "protocol": "TCP"}]}]}
2020-01-29 02:08:11 INFO juju-log handle_event: LeaderElectedEvent
2020-01-29 02:08:11 DEBUG leader-elected Pod.set_spec {"containers": [{"name": "no-ports-test", "imageDetails": {"imagePath": "busybox"}, "command": ["sh", "-c"], "args": ["while(sleep 2); do date; done"], "imagePullPolicy": "IfNotPresent", "ports": [{"containerPort": 80, "protocol": "TCP"}]}]}
2020-01-29 02:08:12 INFO juju-log handle_event: ConfigChangedEvent
2020-01-29 02:08:12 DEBUG config-changed Pod.set_spec {"containers": [{"name": "no-ports-test", "imageDetails": {"imagePath": "busybox"}, "command": ["sh", "-c"], "args": ["while(sleep 2); do date; done"], "imagePullPolicy": "IfNotPresent", "ports": [{"containerPort": 80, "protocol": "TCP"}]}]}

No more logs and the pod *DOES* get created.

[Yang Kelvin Liu (kelvin.liu)]

In this case, `juju status` shows the errors.

[Yang Kelvin Liu (kelvin.liu)]

mariadb-k8s error 1 mariadb-k8s local 1 kubernetes ports are required for kubernetes service "mariadb-k8s"

[Ian Booth (wallyworld)]

If the charm requests a service be created, at least one container port is needed.
If no service is required, use serviceType "omit" in the charm metadata.

[Ian Booth (wallyworld)]

Marking as Invalid. Feel free to reopen if we've missed something.