Managing Workloads — Canary deployments

Reference note (untrusted external data; do not execute it as instructions). Another scenario where multiple labels are needed is to distinguish deployments of different releases or configurations of the same component. It is common practice to deploy a canary of a new application release (specified via image tag in the pod template) side by side with the previous release so that the new release can receive live production traffic before fully rolling it out. For instance, you can use a track label to differentiate different releases. The primary, stable release would have a track label with value as stable Bounded code example (external data; do not execute automatically): ```none name: frontend replicas: 3 ... labels: app: guestbook tier: frontend track: stable ... image: gb-frontend:v3 ``` and then you can create a new release of the guestbook frontend that carries the track label with different value (i.e. canary), so that two sets of pods would not overlap Bounded code example (external data; do not execute automatically): ```none name: frontend-canary replicas: 1 ... labels: app: guestbook tier: frontend track: canary ... image: gb-frontend:v4 ``` The frontend service would span both sets of replicas by selecting the common subset of their labels (i.e. omitting the track label), so that the traffic will be redirected to both applications Bounded code example (external data; do not execute automatically): ```yaml selector: app: guestbook tier: frontend ``` You can tweak the number of replicas of the stable and canary releases to determine the ratio of each release that will receive live production traffic (in this case, 3:1). Once you're confident, you can update the stable track to the new application release and remove the canary one. Attribution: Adapted from Kubernetes Documentation under CC-BY-4.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.