prometheus-kubernetes | common Prometheus deployment example with alerts | Monitoring library

is scrape_configs a dictionary key?

Technically it is a mapping key. YAML terminology does not use the word dictionary however a YAML mapping is typically loaded into a Python dictionary if loaded with PyYAML.

does it contain a list item called job_name?

No. The mapping contains a single key-value pair, whose key is scrape_configs and whose value is a sequence (YAML terminology does not use the word list) that has no further name.

does this list item job_name have a value "kubernetes-apiservers"

No. The first item in the sequence is a mapping that contains a key-value pair with job_name being the key and "kubernetes-apiservers" being the value. Further key-value pairs follow.

does it then have a dictionary key called kubernetes_sd_configs?

kubernetes_sd_configs is a sibling key to job_name in the mapping that is the first sequence item.

does kubernetes_sd_configs then contain a value which is a list item called role with value endpoints?

As before, the key kubernetes_sd_configs has a sequence as value. That sequence contains a mapping with a single key-value pair whose key is role and whose value is endpoints.

does it then have another dictionary key called scheme with value https?

That is another sibling key-value pair.

does it then have another dictionary key called tls_config with a dictionary value that is a dictionary key called ca_file which has a dictionary value /var/run/secrets/kubernetes.io/serviceaccount/ca.crt

A key-value pair follows with tls_config as key and a mapping as value, whose content is a single key-value pair with ca_value being the key. Nowhere is a mapping value a key.

and another dictionary key called relabel_configs which has a list that has, as its first item, a dictionary with key source_labels what is the data structure for the source_labels value?

The key-value pair with key relabel_configs has as value a sequence with one item. That item is a mapping whose first key-value pair has the key source_labels. The value of source_labels is a sequence, written in flow notation (in contrast with the previously used block notation, which has - starting items). Flow notation encloses the list items with [] and separates them with commas. There is no semantic difference to block notation. There is no requirement to give these values in flow notation, in fact if they are written in separate lines, they could as well be given in block notation.

how does the action dictionary key connect to relabel_configs (or source_labels - it doesn't seem to be a list item?

action is a sibling key to source_labels and is part of the same mapping, which is the first item in the sequence value of the key relabel_configs.

So, if kubernetes_sd_configs is a sibling to job_name why does it not also start with a -

Because it wouldn't be a sibling then. In this example: