Teraslice worker versions should report NA in k8s clustering

[godber]

In k8s mode, I think teraslice currently reports the master version as the teraslice_version for each worker node. It should probably report N/A. Perhaps each worker listed under active should report it's own stats.

    "10.6.6.6": {
        "node_id": "10.6.6.6",
        "hostname": "10.6.6.6",
        "pid": "N/A",
        "node_version": "v8.12.0",
        "teraslice_version": "0.44.4",
        "total": "N/A",
        "state": "connected",
        "available": "N/A",
        "active": [...

[godber]

Erik also asked about adding information about the execution controller to cluster state as well.

[godber]

Rather than reporting NA, it could report the worker's version (doing so would be ideal). I am not sure what's involved in that, probably a lot of fiddly messaging that may not be worth the effort. Unless it's stored in the deployment, oh, it probably is.

[peterdemartini]

I think the reason why we used N/A was not that it was difficult to get information but the "node" could potentially have many executions running on it, with different teraslice versions.

[godber]

Ok, for now, I am going to do this:

• Set node_version and teraslice_version to N/A at the worker/node level since it doesn't really have meaning in the k8s case (there's not node manager, a single node can run workers with versions that differ)
• Add an image property that reports the docker image used, including tag, which in our case provides version and build information.

I think this solution makes a decent compromise, maybe the /txt output should show image instead of node_version and teraslice_version in the k8s master case. We haven't introduced any differences at the /txt api based on cluster type, but I'll see if doing so is convenient.

[godber]

/txt/workers will now read more usefully:

######  Workers  ######

assignment  job_id  ex_id  node_id    pod_name                           image
----------  ------  -----  ---------  ---------------------------------  ------------------
master      N/A     N/A    10.0.2.15  teraslice-master-794bdf85f6-dl49k  teraslice-k8sdev:1