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Sunil Singh
70 lines
2.7 KiB
Markdown
70 lines
2.7 KiB
Markdown
---
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title: Working with Taints and Tolerations
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---
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<head>
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<link rel="canonical" href="https://ranchermanager.docs.rancher.com/integrations-in-rancher/logging/taints-and-tolerations"/>
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</head>
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"Tainting" a Kubernetes node causes pods to repel running on that node.
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Unless the pods have a `toleration` for that node's taint, they will run on other nodes in the cluster.
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[Taints and tolerations](https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/) can work in conjunction with the `nodeSelector` [field](https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#nodeselector) within the `PodSpec`, which enables the *opposite* effect of a taint.
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Using `nodeSelector` gives pods an affinity towards certain nodes.
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Both provide choice for the what node(s) the pod will run on.
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- [Default Implementation in Rancher's Logging Stack](#default-implementation-in-ranchers-logging-stack)
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- [Adding NodeSelector Settings and Tolerations for Custom Taints](#adding-nodeselector-settings-and-tolerations-for-custom-taints)
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## Default Implementation in Rancher's Logging Stack
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By default, Rancher taints all Linux nodes with `cattle.io/os=linux`, and does not taint Windows nodes.
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The logging stack pods have `tolerations` for this taint, which enables them to run on Linux nodes.
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Moreover, most logging stack pods run on Linux only and have a `nodeSelector` added to ensure they run on Linux nodes.
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This example Pod YAML file shows a nodeSelector being used with a toleration:
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```yaml
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apiVersion: v1
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kind: Pod
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# metadata...
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spec:
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# containers...
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tolerations:
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- key: cattle.io/os
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operator: "Equal"
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value: "linux"
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effect: NoSchedule
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nodeSelector:
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kubernetes.io/os: linux
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```
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In the above example, we ensure that our pod only runs on Linux nodes, and we add a `toleration` for the taint we have on all of our Linux nodes.
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You can do the same with Rancher's existing taints, or with your own custom ones.
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## Adding NodeSelector Settings and Tolerations for Custom Taints
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If you would like to add your own `nodeSelector` settings, or if you would like to add `tolerations` for additional taints, you can pass the following to the chart's values.
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```yaml
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tolerations:
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# insert tolerations...
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nodeSelector:
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# insert nodeSelector...
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```
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These values will add both settings to the `fluentd`, `fluentbit`, and `logging-operator` containers.
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Essentially, these are global settings for all pods in the logging stack.
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However, if you would like to add tolerations for *only* the `fluentbit` container, you can add the following to the chart's values.
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```yaml
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fluentbit_tolerations:
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# insert tolerations list for fluentbit containers only...
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```
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