From 8e490b4251601507ead8f853a2fb0c74431aa280 Mon Sep 17 00:00:00 2001 From: Harry Zhang Date: Sat, 18 Feb 2017 03:06:01 +0800 Subject: [PATCH] Add kubelet eviction in GC doc (#2484) --- docs/admin/garbage-collection.md | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/docs/admin/garbage-collection.md b/docs/admin/garbage-collection.md index a960172426..9717a41dd8 100644 --- a/docs/admin/garbage-collection.md +++ b/docs/admin/garbage-collection.md @@ -42,15 +42,34 @@ to free. Default is 80%. We also allow users to customize garbage collection policy through the following kubelet flags: 1. `minimum-container-ttl-duration`, minimum age for a finished container before it is -garbage collected. Default is 1 minute. +garbage collected. Default is 0 minute, which means any finished container will be garbaged collected. 2. `maximum-dead-containers-per-container`, maximum number of old instances to retain -per container. Default is 2. +per container. Default is 1. 3. `maximum-dead-containers`, maximum number of old instances of containers to retain globally. -Default is 100. +Default is -1, which means there is no global limit. Containers can potentially be garbage collected before their usefulness has expired. These containers can contain logs and other data that can be useful for troubleshooting. A sufficiently large value for -`maximum-dead-containers-per-container` is highly recommended to allow at least 2 dead containers to be +`maximum-dead-containers-per-container` is highly recommended to allow at least 1 dead container to be retained per expected container. A higher value for `maximum-dead-containers` is also recommended for a similar reason. See [this issue](https://github.com/kubernetes/kubernetes/issues/13287) for more details. + + +### Deprecation + +Some kubelet Garbage Collection features in this doc will be replaced by kubelet eviction in the future. + +Including: + +| Existing Flag | New Flag | Rationale | +| ------------- | -------- | --------- | +| `--image-gc-high-threshold` | `--eviction-hard` or `eviction-soft` | existing eviction signals can trigger image garbage collection | +| `--image-gc-low-threshold` | `--eviction-minimum-reclaim` | eviction reclaims achieve the same behavior | +| `--maximum-dead-containers` | | deprecated once old logs are stored outside of container's context | +| `--maximum-dead-containers-per-container` | | deprecated once old logs are stored outside of container's context | +| `--minimum-container-ttl-duration` | | deprecated once old logs are stored outside of container's context | +| `--low-diskspace-threshold-mb` | `--eviction-hard` or `eviction-soft` | eviction generalizes disk thresholds to other resources | +| `--outofdisk-transition-frequency` | `--eviction-pressure-transition-period` | eviction generalizes disk pressure transition to other resources | + +See [kubelet eviction design doc](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/kubelet-eviction.md) for more details.