v1alpha2 doesn't work TF.estimator for TF <= 1.6 ; need to add environment:cloud to TF_CONFIG

[jlewi]

See kubeflow/kubeflow#1283

On TF <= 1.6 if you try to use the estimator API with a master the job hangs with

The error is the same "tensorflow:Waiting for model to be ready.  Ready_for_local_init_op:  Variables not initialized:"

The TF_CONIFG looks

TF_CONFIG={"cluster":{"master":["trainer-tfjob2-master-0.default.svc.cluster.local:2222"]},"task":{"type":"master","index":0}}

Its missing Environment which is used in TF 1.6 See here
https://github.com/tensorflow/tensorflow/blob/r1.6/tensorflow/contrib/learn/python/learn/estimators/run_config.py#L146

TF 1.8 doesn't use Environment but it looks like it expects the Chief type.
https://github.com/tensorflow/tensorflow/blob/r1.8/tensorflow/python/estimator/run_config.py#L489

See here:
https://github.com/kubeflow/tf-operator/blob/master/pkg/trainer/replicas.go#L72

[gaocegege]

Could we close the issue? I think we fixed it in #766