Kubernetes batch system can't pick up config from a pod's service account

[adamnovak]

The config loading method we're using to connect to Kubernetes, as described in the module's README, only works when your credentials come from a config file. When they come from a pod's service account, kubectl finds them automatically, but the kubernetes module needs you to manually call a differnet utility method (config.load_incluster_config()) instead.

See:

• Example: https://github.com/kubernetes-client/python/blob/master/examples/in_cluster_config.py

• Implementation/utility method docs: https://github.com/kubernetes-client/python-base/blob/4c1ab55553fa7d0479bd5b270c2b303cb056dd4b/config/incluster_config.py

• Kubernetes issue: Examples show off load_kube_config() as the Right Way to set up the module, but an attempt at load_incluster_config() is also required to match the behavior of kubectl and work form inside pods kubernetes-client/python#1005

┆Issue is synchronized with this Jira Task
┆Issue Number: TOIL-449