apply-ordering.md

Apply ordering

kapp includes builtin rules to make sure certain changes are applied in particular order:

• CRDs and namespaces (predefined change-groups.kapp.k14s.io/crds and change-groups.kapp.k14s.io/namespaces groups) are created before most resources
• CRDs are deleted last (after CRs)

Additionally kapp allows to customize order of changes via following resource annotations:

• kapp.k14s.io/change-group annotation to group one or more resource changes into arbitrarily named group. Example: apps.big.co/db-migrations.
• kapp.k14s.io/change-rule annotation to control when resource change should be applied (created, updated, or deleted) relative to other changes. You can specify multiple change rules by suffixing each annotation with a .x where x is some number (e.g. kapp.k14s.io/change-rule.1).

kapp.k14s.io/change-rule format is as follows: (upsert|delete) (after|before) (upserting|deleting) <name>. For example:

• kapp.k14s.io/change-rule: "upsert after upserting apps.big.co/db-migrations"
• kapp.k14s.io/change-rule: "delete before upserting apps.big.co/service"

Example

Following example shows how to run job/migrations, start and wait for deployment/app, and finally job/app-health-check.

kind: ConfigMap
metadata:
  name: app-config
  annotations: {}
#...
---
kind: Job
metadata:
  name: migrations
  annotations:
    kapp.k14s.io/change-group: "apps.big.co/db-migrations"
#...
---
kind: Service
metadata:
  name: app
  annotations:
    kapp.k14s.io/change-group: "apps.big.co/deployment"
#...
---
kind: Ingress
metadata:
  name: app
  annotations:
    kapp.k14s.io/change-group: "apps.big.co/deployment"
#...
---
kind: Deployment
metadata:
  name: app
  annotations:
    kapp.k14s.io/change-group: "apps.big.co/deployment"
    kapp.k14s.io/change-rule: "upsert after upserting apps.big.co/db-migrations"
#...
---
kind: Job
metadata:
  name: app-health-check
  annotations:
    kapp.k14s.io/change-rule: "upsert after upserting apps.big.co/deployment"
#...