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| author | derekwaynecarr <decarr@redhat.com> | 2016-05-06 17:18:56 -0400 |
|---|---|---|
| committer | derekwaynecarr <decarr@redhat.com> | 2016-05-10 20:24:22 -0400 |
| commit | 33e2c26d10b482b991644f5668f09c4381b088d2 (patch) | |
| tree | 2e19639215927f28cb9ad30766d7895b8ee8cc21 | |
| parent | 24e534e7ea73a7355ca2683254534e675131e52a (diff) | |
Eviction proposal transition frequency
| -rw-r--r-- | kubelet-eviction.md | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kubelet-eviction.md b/kubelet-eviction.md index 485748d3..c62b26aa 100644 --- a/kubelet-eviction.md +++ b/kubelet-eviction.md @@ -155,6 +155,25 @@ The following node conditions are defined that correspond to the specified evict The `kubelet` will continue to report node status updates at the frequency specified by `--node-status-update-frequency` which defaults to `10s`. +### Oscillation of node conditions + +If a node is oscillating above and below a soft eviction threshold, but not exceeding +its associated grace period, it would cause the corresponding node condition to +constantly oscillate between true and false, and could cause poor scheduling decisions +as a consequence. + +To protect against this oscillation, the following flag is defined to control how +long the `kubelet` must wait before transitioning out of a pressure condition. + +``` +--eviction-pressure-transition-period=5m0s: Duration for which the kubelet has to wait +before transitioning out of an eviction pressure condition. +``` + +The `kubelet` would ensure that it has not observed an eviction threshold being met +for the specified pressure condition for the period specified before toggling the +condition back to `false`. + ## Eviction scenario Let's assume the operator started the `kubelet` with the following: |