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Add Circle CI questions
In addition to a couple of k8s questions.
This commit is contained in:
abregman
@@ -12,7 +12,9 @@
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- [Deployments](#deployments)
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- [Troubleshooting Deployments](#troubleshooting-deployments)
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- [Scheduler](#scheduler)
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- [Node Affinity](#node-affinity)
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- [Labels and Selectors](#labels-and-selectors)
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- [Node Selector](#node-selector)
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- [Taints](#taints)
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## Setup
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@@ -537,6 +539,45 @@ spec:
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Note: if you don't have a node1 in your cluster the Pod will be stuck on "Pending" state.
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</b></details>
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### Node Affinity
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<details>
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<summary>Using node affinity, set a Pod to schedule on a node where the key is "region" and value is either "asia" or "emea"</summary><br><b>
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`vi pod.yaml`
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```yaml
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affinity:
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nodeAffinity:
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requiredDuringSchedlingIgnoredDuringExecution:
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nodeSelectorTerms:
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- matchExpressions:
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- key: region
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operator: In
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values:
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- asia
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- emea
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```
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</b></details>
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<details>
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<summary>Using node affinity, set a Pod to never schedule on a node where the key is "region" and value is "neverland"</summary><br><b>
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`vi pod.yaml`
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```yaml
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affinity:
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nodeAffinity:
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requiredDuringSchedlingIgnoredDuringExecution:
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nodeSelectorTerms:
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- matchExpressions:
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- key: region
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operator: NotIn
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values:
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- neverland
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```
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</b></details>
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## Labels and Selectors
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<details>
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@@ -557,6 +598,38 @@ Note: if you don't have a node1 in your cluster the Pod will be stuck on "Pendin
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`k get deploy -l env=prod,type=web`
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</b></details>
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### Node Selector
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<details>
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<summary>Apply the label "hw=max" on one of the nodes in your cluster</summary><br><b>
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`kubectl label nodes some-node hw=max`
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</b></details>
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<details>
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<summary>reate and run a Pod called `some-pod` with the image `redis` and configure it to use the selector `hw=max`</summary><br><b>
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```
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kubectl run some-pod --image=redis --dry-run=client -o yaml > pod.yaml
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vi pod.yaml
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spec:
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nodeSelector:
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hw: max
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kubectl apply -f pod.yaml
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```
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</b></details>
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<details>
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<summary>Explain why node selectors might be limited</summary><br><b>
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Assume you would like to run your Pod on all the nodes with with either `hw` set to max or to min, instead of just max. This is not possible with nodeSelectors which are quite simplified and this is where you might want to consider `node affinity`.
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</b></details>
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## Taints
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<details>
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@@ -566,7 +639,36 @@ Note: if you don't have a node1 in your cluster the Pod will be stuck on "Pendin
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</b></details>
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<details>
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<summary>Create a taint on one of the nodes in your cluster with key of "app" and value of "web" and effect of "NoSchedule"</summary><br><b>
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<summary>Create a taint on one of the nodes in your cluster with key of "app" and value of "web" and effect of "NoSchedule". Verify it was applied</summary><br><b>
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`k taint node minikube app=web:NoSchedule`
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`k describe no minikube | grep -i taints`
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</b></details>
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<details>
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<summary>You applied a taint with <code>k taint node minikube app=web:NoSchedule</code> on the only node in your cluster and then executed <code>kubectl run some-pod --image=redis</code>. What will happen?</summary><br><b>
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The Pod will remain in "Pending" status due to the only node in the cluster having a taint of "app=web".
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</b></details>
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<details>
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<summary>You applied a taint with <code>k taint node minikube app=web:NoSchedule</code> on the only node in your cluster and then executed <code>kubectl run some-pod --image=redis</code> but the Pod is in pending state. How to fix it?</summary><br><b>
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`kubectl edit po some-pod` and add the following
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```
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- effect: NoSchedule
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key: app
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operator: Equal
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value: web
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```
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Exit and save. The pod should be in Running state now.
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</b></details>
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<details>
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<summary>Remove an existing taint from one of the nodes in your cluster</summary><br><b>
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`k taint node minikube app=web:NoSchedule-`
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</b></details>
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@@ -48,6 +48,7 @@ What's your goal?
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- [Istio](#istio)
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- [Controllers](#controllers)
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- [Scheduler](#scheduler-1)
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- [Node Affinity](#node-affinity)
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- [Taints](#taints)
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- [Scenarios](#scenarios)
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@@ -79,6 +80,8 @@ What's your goal?
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|Name|Topic|Objective & Instructions|Solution|Comments|
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|--------|--------|------|----|----|
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| Labels and Selectors 101 | Labels, Selectors | [Exercise](exercises/labels_and_selectors/exercise.md) | [Solution](exercises/labels_and_selectors/solution.md)
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| Node Selectors | Labels, Selectors | [Exercise](exercises/node_selectors/exercise.md) | [Solution](exercises/node_selectors/solution.md)
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### Scheduler
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@@ -2475,6 +2478,57 @@ spec:
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Note: if you don't have a node1 in your cluster the Pod will be stuck on "Pending" state.
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</b></details>
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#### Node Affinity
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<details>
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<summary>Using node affinity, set a Pod to schedule on a node where the key is "region" and value is either "asia" or "emea"</summary><br><b>
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`vi pod.yaml`
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```yaml
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affinity:
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nodeAffinity:
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requiredDuringSchedlingIgnoredDuringExecution:
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nodeSelectorTerms:
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- matchExpressions:
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- key: region
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operator: In
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values:
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- asia
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- emea
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```
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</b></details>
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<details>
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<summary>Using node affinity, set a Pod to never schedule on a node where the key is "region" and value is "neverland"</summary><br><b>
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`vi pod.yaml`
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```yaml
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affinity:
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nodeAffinity:
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requiredDuringSchedlingIgnoredDuringExecution:
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nodeSelectorTerms:
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- matchExpressions:
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- key: region
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operator: NotIn
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values:
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- neverland
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```
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</b></details>
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<details>
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<summary>True of False? Using the node affinity type "requiredDuringSchedlingIgnoredDuringExecution" means the scheduler can't schedule unless the rule is met</summary><br><b>
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True
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</b></details>
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<details>
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<summary>True of False? Using the node affinity type "preferredDuringSchedlingIgnoredDuringExecution" means the scheduler can't schedule unless the rule is met</summary><br><b>
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False. The scheduler tries to find a node that meets the requirements/rules and if it doesn't it will schedule the Pod anyway.
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</b></details>
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## Taints
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<details>
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@@ -2484,9 +2538,38 @@ Note: if you don't have a node1 in your cluster the Pod will be stuck on "Pendin
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</b></details>
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<details>
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<summary>Create a taint on one of the nodes in your cluster with key of "app" and value of "web" and effect of "NoSchedule"</summary><br><b>
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<summary>Create a taint on one of the nodes in your cluster with key of "app" and value of "web" and effect of "NoSchedule". Verify it was applied</summary><br><b>
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`k taint node minikube app=web:NoSchedule`
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`k describe no minikube | grep -i taints`
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</b></details>
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<details>
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<summary>You applied a taint with <code>k taint node minikube app=web:NoSchedule</code> on the only node in your cluster and then executed <code>kubectl run some-pod --image=redis</code>. What will happen?</summary><br><b>
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The Pod will remain in "Pending" status due to the only node in the cluster having a taint of "app=web".
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</b></details>
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<details>
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<summary>You applied a taint with <code>k taint node minikube app=web:NoSchedule</code> on the only node in your cluster and then executed <code>kubectl run some-pod --image=redis</code> but the Pod is in pending state. How to fix it?</summary><br><b>
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`kubectl edit po some-pod` and add the following
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```
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- effect: NoSchedule
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key: app
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operator: Equal
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value: web
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```
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Exit and save. The pod should be in Running state now.
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</b></details>
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<details>
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<summary>Remove an existing taint from one of the nodes in your cluster</summary><br><b>
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`k taint node minikube app=web:NoSchedule-`
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</b></details>
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<details>
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12
topics/kubernetes/exercises/node_selectors/exercise.md
Normal file
12
topics/kubernetes/exercises/node_selectors/exercise.md
Normal file
@@ -0,0 +1,12 @@
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# Node Selectors
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## Objectives
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1. Apply the label "hw=max" on one of the nodes in your cluster
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2. Create and run a Pod called `some-pod` with the image `redis` and configure it to use the selector `hw=max`
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3. Explain why node selectors might be limited
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## Solution
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Click [here](solution.md) to view the solution
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29
topics/kubernetes/exercises/node_selectors/solution.md
Normal file
29
topics/kubernetes/exercises/node_selectors/solution.md
Normal file
@@ -0,0 +1,29 @@
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# Node Selectors
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## Objectives
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1. Apply the label "hw=max" on one of the nodes in your cluster
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2. Create and run a Pod called `some-pod` with the image `redis` and configure it to use the selector `hw=max`
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3. Explain why node selectors might be limited
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## Solution
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Click [here](solution.md) to view the solution
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1. `kubectl label nodes some-node hw=max`
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2.
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```
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kubectl run some-pod --image=redis --dry-run=client -o yaml > pod.yaml
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vi pod.yaml
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spec:
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nodeSelector:
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hw: max
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kubectl apply -f pod.yaml
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```
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3. Assume you would like to run your Pod on all the nodes with with either `hw` set to max or to min, instead of just max. This is not possible with nodeSelectors which are quite simplified and this is where you might want to consider `node affinity`.
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@@ -6,12 +6,8 @@
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2. Create a taint on one of the nodes in your cluster with key of "app" and value of "web" and effect of "NoSchedule"
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1. Explain what it does exactly
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2. Verify it was applied
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3. Run a Pod that will be able to run on the node on which you applied the taint
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## Solution
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Click [here](solution.md) to view the solution.
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1. `kubectl describe no minikube | grep -i taints`
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2. `kubectl taint node minikube app=web:NoSchedule`
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1. Any resource with "app=web" key value will not be scheduled on node `minikube`
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2. `kubectl describe no minikube | grep -i taints`
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Click [here](solution.md) to view the solution.
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30
topics/kubernetes/exercises/taints_101/solution.md
Normal file
30
topics/kubernetes/exercises/taints_101/solution.md
Normal file
@@ -0,0 +1,30 @@
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# Taints 101
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## Objectives
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1. Check if one of the nodes in the cluster has taints (doesn't matter which node)
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2. Create a taint on one of the nodes in your cluster with key of "app" and value of "web" and effect of "NoSchedule"
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1. Explain what it does exactly
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2. Verify it was applied
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## Solution
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1. `kubectl describe no minikube | grep -i taints`
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2. `kubectl taint node minikube app=web:NoSchedule`
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1. Any resource with "app=web" key value will not be scheduled on node `minikube`
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2. `kubectl describe no minikube | grep -i taints`
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3.
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```
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kubectl run some-pod --image=redis
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kubectl edit po some-pod
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```
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```
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- effect: NoSchedule
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key: app
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operator: Equal
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value: web
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```
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Save and exit. The Pod should be running.
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Reference in New Issue
Block a user