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Deviation#

A deviation is a report indicating differences between the actual device or system configuration and the configuration specified in one or more Config CRs managed by SDC.

There are three types of deviations:

  1. UNHANDLED

    • No matching Config CR exists in the system.
    • Treated as a Target-type deviation.
    • SDC only reports these deviations; no corrective action is taken.

  2. NOT-APPLIED

    • A matching Config CR exists, but the actual configuration differs from what is defined in the Config CR.
    • SDC will act on these deviations based on the configured mode: revertive or non-revertive.

  3. OVERRULED

    • A matching Config CR exists, but the actual configuration has been overridden by a higher-priority intent.
    • SDC reports these deviations but does not attempt to change the overriding configuration.

SDC automatically creates a deviation per target CR and one for each config CR. By default when no config CR exists all brownfield configuration is reported as a UNHANDLED deviation per target.

Revertive vs. Non-Revertive Behavior#

  • Revertive mode

SDC will automatically reapply the Config CR when a NOT-APPLIED deviation is detected, restoring the intended configuration.

  • Non-revertive mode

SDC will treat the deviation as part of the active configuration.

To clear a deviation we can select the deviations using the clear deviation logic in kubectl-sdc

kubectl-sdc deviation

To change revertive or non revetive behavior can be done either: - globally: as part of the deployment environment variables of the config-server

        - name: REVERTIVE
          value: "true"

Example:#

kubectl get deviations.config.sdcio.dev 

NAME                                           TYPE     TARGET           DEVIATIONS
deviation.config.sdcio.dev/configset1-core01   config   default/core01   0
deviation.config.sdcio.dev/configset1-edge01   config   default/edge01   0
deviation.config.sdcio.dev/configset1-edge02   config   default/edge02   0
deviation.config.sdcio.dev/core01              target   default/core01   600
deviation.config.sdcio.dev/edge01              target   default/edge01   602
deviation.config.sdcio.dev/edge02              target   default/edge02   602
deviation.config.sdcio.dev/test                config   default/core01   0