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PriorityClass
es in Gardener Clusters
Gardener makes use of PriorityClass
es to improve the overall robustness of the system.
In order to benefit from the full potential of PriorityClass
es, the gardenlet manages a set of well-known PriorityClass
es with fine-granular priority values.
All components of the system should use these well-known PriorityClass
es instead of creating and using separate ones with arbitrary values, which would compromise the overall goal of using PriorityClass
es in the first place.
The gardenlet manages the well-known PriorityClass
es listed in this document, so that third parties (e.g., Gardener extensions) can rely on them to be present when deploying components to Seed and Shoot clusters.
The listed well-known PriorityClass
es follow this rough concept:
- Values are close to the maximum that can be declared by the user. This is important to ensure that Shoot system components have higher priority than the workload deployed by end-users.
- Values have a bit of headroom in between to ensure flexibility when the need for intermediate priority values arises.
- Values of
PriorityClass
es created on Seed clusters are lower than the ones on Shoots to ensure that Shoot system components have higher priority than Seed components, if the Seed is backed by a Shoot (ManagedSeed
), e.g.coredns
should have higher priority thangardenlet
. - Names simply include the last digits of the value to minimize confusion caused by many (similar) names like
critical
,importance-high
, etc.
Garden Clusters
When using the gardener-operator
for managing the garden runtime and virtual cluster, the following PriorityClass
es are available:
PriorityClass
es for Garden Control Plane Components
Name | Priority | Associated Components (Examples) |
---|---|---|
gardener-garden-system-critical | 999999550 | gardener-operator , gardener-resource-manager , istio |
gardener-garden-system-500 | 999999500 | virtual-garden-etcd-events , virtual-garden-etcd-main , virtual-garden-kube-apiserver , gardener-apiserver |
gardener-garden-system-400 | 999999400 | virtual-garden-gardener-resource-manager , gardener-admission-controller , Extension Admission Controllers |
gardener-garden-system-300 | 999999300 | virtual-garden-kube-controller-manager , vpa-admission-controller , etcd-druid , nginx-ingress-controller |
gardener-garden-system-200 | 999999200 | vpa-recommender , vpa-updater , gardener-scheduler , gardener-controller-manager , gardener-dashboard , terminal-controller-manager , gardener-discovery-server , Extension Controllers |
gardener-garden-system-100 | 999999100 | fluent-operator , fluent-bit , gardener-metrics-exporter , kube-state-metrics , plutono , vali , prometheus-operator , alertmanager-garden , prometheus-garden , blackbox-exporter , prometheus-longterm |
Seed Clusters
PriorityClass
es for Seed System Components
Name | Priority | Associated Components (Examples) |
---|---|---|
gardener-system-critical | 999998950 | gardenlet , gardener-resource-manager , istio-ingressgateway , istiod |
gardener-system-900 | 999998900 | Extensions, reversed-vpn-auth-server |
gardener-system-800 | 999998800 | dependency-watchdog-endpoint , dependency-watchdog-probe , etcd-druid , vpa-admission-controller |
gardener-system-700 | 999998700 | vpa-recommender , vpa-updater |
gardener-system-600 | 999998600 | alertmanager-seed , fluent-operator , fluent-bit , plutono , kube-state-metrics , nginx-ingress-controller , nginx-k8s-backend , prometheus-operator , prometheus-aggregate , prometheus-cache , prometheus-seed , vali |
gardener-reserve-excess-capacity | -5 | reserve-excess-capacity (ref) |
PriorityClass
es for Shoot Control Plane Components
Name | Priority | Associated Components (Examples) |
---|---|---|
gardener-system-500 | 999998500 | etcd-events , etcd-main , kube-apiserver |
gardener-system-400 | 999998400 | gardener-resource-manager |
gardener-system-300 | 999998300 | cloud-controller-manager , cluster-autoscaler , csi-driver-controller , kube-controller-manager , kube-scheduler , machine-controller-manager , terraformer , vpn-seed-server |
gardener-system-200 | 999998200 | csi-snapshot-controller , csi-snapshot-validation , cert-controller-manager , shoot-dns-service , vpa-admission-controller , vpa-recommender , vpa-updater |
gardener-system-100 | 999998100 | alertmanager-shoot , plutono , kube-state-metrics , prometheus-shoot , blackbox-exporter , vali , event-logger |
Shoot Clusters
PriorityClass
es for Shoot System Components
Name | Priority | Associated Components (Examples) |
---|---|---|
system-node-critical (created by Kubernetes) | 2000001000 | calico-node , kube-proxy , apiserver-proxy , csi-driver , egress-filter-applier |
system-cluster-critical (created by Kubernetes) | 2000000000 | calico-typha , calico-kube-controllers , coredns , vpn-shoot , registry-cache |
gardener-shoot-system-900 | 999999900 | node-problem-detector |
gardener-shoot-system-800 | 999999800 | calico-typha-horizontal-autoscaler , calico-typha-vertical-autoscaler |
gardener-shoot-system-700 | 999999700 | blackbox-exporter , node-exporter |
gardener-shoot-system-600 | 999999600 | addons-nginx-ingress-controller , addons-nginx-ingress-k8s-backend , kubernetes-dashboard , kubernetes-metrics-scraper |