Label terminology

(This is broadly based on the k8s label document)

Labels are made up of key/value pairs.

For querying, a label_selector is used.

Label Keys

Label keys are made up of an (optional) prefix, and name. If a prefix is present, it is separated from the name by a /.

• without a prefix: release
• with a prefix: example.com/release

Label key prefix

• Length restriction: 0-253 characters
• Character restriction: DNS subdomain format (series of subdomain labels separated by .)
• Valid examples:
  • beeblebrox
  • example.com
  • foo.bar.baz.somewhere.over.the.rainbow.capi.land
  • (literally empty)
• Invalid examples:
  • .fun
  • dope.
  • foo..bar
  • @#$(@(
  • this.is.entirely.too.long.of.a.prefix.so.there.you.have.it.like.super.long.omg.it.repeats.this.is.entirely.too.long.of.a.prefix.so.there.you.have.it.like.super.long.omg.it.repeats.this.is.entirely.too.long.of.a.prefix.so.there.you.have.it.like.super.long

Label key name

• Length restriction: 1-63 characters
• Character restriction: alphanumeric with -, _, and . allowed. Must begin and end with alphanumeric.
• Valid examples:
  • release_v1_duh
  • Production-cluster
  • billing.system.1234.foo
• Invalid examples:
  • 1Direction
  • yoooooooooooooooooooooooooooooooooooooooooooThisIsLikeTooLongBrah
  • Datacenter-US-1
  • Something~Or

Label Values

• Length restriction: 0-63 characters
• Character restriction: alphanumeric with -, _, and . allowed. Must begin and end with alphanumeric.
• Valid examples:
  • environment_v7_ultra
  • (literally empty)
  • Current-version
  • state.county.wa.king
• Invalid examples:
  • 98Degrees
  • heyyoooooooooooooooooooooooooooooooooooooooooooWayTooLongMadame
  • Lets.count.to.10
  • Legend~~Of&&The##Forbidden@@Characters

Label Selectors

Each label_selector consists of one or more requirements, separated by a comma.