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Fixed layout issue in the consolidation section #277

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Fixed layout issue in the consolidation section #277

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18 changes: 15 additions & 3 deletions content/karpenter/050_karpenter/consolidation.md
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Expand Up @@ -7,7 +7,6 @@ draft: false

{{% notice info %}}
Please note: this EKS and Karpenter workshop version is now deprecated since the launch of Karpenter v1beta, and has been updated to a new home on AWS Workshop Studio here: **[Karpenter: Amazon EKS Best Practice and Cloud Cost Optimization](https://catalog.us-east-1.prod.workshops.aws/workshops/f6b4587e-b8a5-4a43-be87-26bd85a70aba)**.

This workshop remains here for reference to those who have used this workshop before, or those who want to reference this workshop for running Karpenter on version v1alpha5.
{{% /notice %}}

Expand Down Expand Up @@ -133,7 +132,9 @@ The log does also show something interesting lines that refer to `Cordon` and `D
{{% /expand %}}

#### 2) What should happen when we move to just 3 replicas ?
{{%expand "Click here to show the answer" %}}

{{%expand "Click here to show the answer" %}}

To scale up the deployment run the following command:

```
Expand All @@ -151,11 +152,12 @@ Karpenter logs will show the sequence of events on the output, similar to the on
2022-09-05T08:37:38.649Z INFO controller.termination Deleted node {"commit": "b157d45", "node": "ip-192-168-15-83.eu-west-1.compute.internal"}
```


{{% /expand %}}

#### 3) Increase the replicas to 10. What will happen if we change the provisioner to support both `on-demand` and `spot` ?

{{%expand "Click here to show the answer" %}}

To scale up the deployment bach to 10 ,run the following command:

```
Expand All @@ -165,6 +167,7 @@ kubectl scale deployment inflate --replicas 10
There should not be any surprise here, like in previous cases a new **2xlarge** node might be selected to place the extra 7 pods. Note, the provisioned instance type can depend on available spot capacity.

To apply the change to the provisioner, we will re-deploy the default provisioner, this time using both `on-demand` and `spot`. Run the following command

```
cat <<EOF | kubectl apply -f -
apiVersion: karpenter.sh/v1alpha5
Expand Down Expand Up @@ -225,7 +228,10 @@ Karpenter logs should show a sequence of events similar to the one below.
2022-09-05T08:57:06.000Z INFO controller.termination Deleted node {"commit": "b157d45", "node": "ip-192-168-8-39.eu-west-1.compute.internal"}
```

{{% /expand %}}

#### 4) Scale the `inflate` service to 3 replicas, what should happen ?

{{%expand "Click here to show the answer" %}}

Run the following command to set the number of replicas to 3.
Expand All @@ -237,9 +243,11 @@ kubectl scale deployment inflate --replicas 3
For spot nodes, Karpenter only uses the **Deletion** consolidation mechanism. It will not replace a spot node with a cheaper spot node. Spot instance types are selected with the `price-capacity-optimized` strategy and often the cheapest spot instance type is not launched due to the likelihood of interruption. Consolidation would then replace the spot instance with a cheaper instance negating the `price-capacity-optimized` strategy entirely and increasing interruption rate.

Effectively no changes will happen at this stage with your cluster.

{{% /expand %}}

#### 5) What other scenarios could prevent **Consolidation** events in your cluster ?

{{%expand "Click here to show the answer" %}}

There are a few cases where requesting to deprovision a Karpenter node will not work. These include **Pod Disruption Budgets** and pods that have the **do-not-evict** annotation set.
Expand All @@ -254,16 +262,20 @@ There are other cases that Karpenter will consider when consolidating. Consolida
* or some other scheduling restriction that couldn’t be fulfilled.

Finally, Karpenter consolidation will not attempt to consolidate a node that is running pods that are not owned by a controller (e.g. a ReplicaSet). In general we cannot assume that these pods would be recreated if they were evicted from the node that they are currently running on.

{{% /expand %}}

#### 6) Scale the replicas to 0.

{{%expand "Click here to show the answer" %}}

In preparation for the next section, scale replicas to 0 using the following command.

```
kubectl scale deployment inflate --replicas 0
```

{{% /expand %}}

## What Have we learned in this section:

Expand Down