[Superseded by ADR-0017] Do not persist Dex

  • Status: superseded by ADR-0017
  • Deciders: Compliant Kubernetes Architecture Meeting
  • Date: 2021-04-29

Technical Story: Reduce Helmfile concurrency for improved predictability

Context and Problem Statement

Dex requires persisting state to perform various tasks such as track refresh tokens, preventing replays, and rotating keys.

What persistence option should we use?

Decision Drivers

  • CRDs add complexity
  • Storage adds complexity

Considered Options

Decision Outcome

Chosen option: "use memory", because it simplified operations with little negative impact.

Positive Consequences

  • Dex brings no additional CRDs, which simplified upgrades.
  • Dex brings no state, which simplified upgrades.

Negative Consequences

  • The authentication flow is disrupted, if Dex is rebooted exactly during an authentication flow. There is no user impact if Dex is restarted after the JWT was issued. Cristian tested this with kubectl and Grafana. Since we will only reboot Dex during maintenance windows, this is unlikely to be an issue in the foreseeable future.

Other Considerations

If Dex becomes a bottleneck and needs replication, or if we want to avoid disrupting authentication flows during operations on Dex, we will have to revisit this ADR.