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docs: Update settings doc to v1beta1 apis (#4778)
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jonathan-innis authored Oct 10, 2023
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Expand Up @@ -6,9 +6,7 @@ description: >
Configure Karpenter
---

There are two main configuration mechanisms that can be used to configure Karpenter: Environment Variables / CLI parameters to the controller and webhook binaries and the `karpenter-global-settings` config-map.

## Environment Variables / CLI Flags
Karpenter surfaces environment variables and CLI parameters to allow you to configure certain global settings on the controllers. These settings are described below.

[comment]: <> (the content below is generated from hack/docs/configuration_gen_docs.go)

Expand All @@ -21,105 +19,37 @@ There are two main configuration mechanisms that can be used to configure Karpen
| KUBE_CLIENT_BURST | \-\-kube-client-burst | The maximum allowed burst of queries to the kube-apiserver (default = 300)|
| KUBE_CLIENT_QPS | \-\-kube-client-qps | The smoothed rate of qps to kube-apiserver (default = 200)|
| LEADER_ELECT | \-\-leader-elect | Start leader election client and gain leadership before executing the main loop. Enable this when running replicated components for high availability. (default = true)|
| LOG_LEVEL | \-\-log-level | Log verbosity level. Can be one of 'debug', 'info', or 'error'|
| MEMORY_LIMIT | \-\-memory-limit | Memory limit on the container running the controller. The GC soft memory limit is set to 90% of this value. (default = -1)|
| METRICS_PORT | \-\-metrics-port | The port the metric endpoint binds to for operating metrics about the controller itself (default = 8000)|
| WEBHOOK_METRICS_PORT | \-\-webhook-metrics-port | The port the webhook metric endpoing binds to for operating metrics about the webhook (default = 8001)|
| WEBHOOK_PORT | \-\-webhook-port | The port the webhook endpoint binds to for validation and mutation of resources (default = 8443)|

[comment]: <> (end docs generated content from hack/docs/configuration_gen_docs.go)

## ConfigMap

Karpenter installs a default configuration via its Helm chart that should work for most. Additional configuration can be performed by editing the `karpenter-global-settings` configmap within the namespace that Karpenter was installed in.

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: karpenter-global-settings
namespace: karpenter
data:
# The maximum length of a batch window. The longer this is, the more pods we can consider for provisioning at one
# time which usually results in fewer but larger nodes.
batchMaxDuration: 10s
# The maximum amount of time with no new pending pods that if exceeded ends the current batching window. If pods arrive
# faster than this time, the batching window will be extended up to the maxDuration. If they arrive slower, the pods
# will be batched separately.
batchIdleDuration: 1s
# Role to assume for calling AWS services.
aws.assumeRoleARN: arn:aws:iam::111222333444:role/examplerole
# Duration of assumed credentials in minutes. Default value is 15 minutes. Not used unless aws.assumeRole set.
aws.assumeRoleDuration: 15m
# Cluster CA bundle for nodes to use for TLS connections with the API server. If not set, this is taken from the controller's TLS configuration.
aws.clusterCABundle: "LS0tLS1..."
# [REQUIRED] The kubernetes cluster name for resource discovery
aws.clusterName: karpenter-cluster
# The external kubernetes cluster endpoint for new nodes to connect with. If not specified, will discover the cluster endpoint using DescribeCluster API
aws.clusterEndpoint: https://00000000000000000000000000000000.gr7.us-west-2.eks.amazonaws.com
# The default instance profile to use when provisioning nodes
aws.defaultInstanceProfile: karpenter-instance-profile
# If true, then instances that support pod ENI will report a vpc.amazonaws.com/pod-eni resource
aws.enablePodENI: "false"
# Indicates whether new nodes should use ENI-based pod density. DEPRECATED: Use `.spec.kubeletConfiguration.maxPods` to set pod density on a per-provisioner basis
aws.enableENILimitedPodDensity: "true"
# If true, then assume we can't reach AWS services which don't have a VPC endpoint
# This also has the effect of disabling look-ups to the AWS pricing endpoint
aws.isolatedVPC: "false"
# The VM memory overhead as a percent that will be subtracted
# from the total memory for all instance types
aws.vmMemoryOverheadPercent: "0.075"
# aws.interruptionQueueName is disabled if not specified. Enabling interruption handling may
# require additional permissions on the controller service account. Additional permissions are outlined in the docs
aws.interruptionQueueName: karpenter-cluster
# Global tags are specified by including a JSON object of string to string from tag key to tag value
aws.tags: '{"custom-tag1-key": "custom-tag-value", "custom-tag2-key": "custom-tag-value"}'
# Reserved ENIs are not included in the calculations for max-pods or kube-reserved
# This is most often used in the VPC CNI custom networking setup https://docs.aws.amazon.com/eks/latest/userguide/cni-custom-network.html
aws.reservedENIs: "1"
```
### Feature Gates
Karpenter uses [feature gates](https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/#feature-gates-for-alpha-or-beta-features). You can add a feature gate's ConfigKey to the `karpenter-global-settings` ConfigMap above with the desired value.

| Feature | Default | Config Key | Stage | Since | Until |
|---------|---------|---------------------------|-------|---------|-------|
| Drift | false | featureGates.driftEnabled | Alpha | v0.21.0 | |
Karpenter uses [feature gates](https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/#feature-gates-for-alpha-or-beta-features) You can enable the feature gates through the `--feature-gates` CLI environment variable or the `FEATURE_GATES` environment variable in the Karpenter deployment. For example, you can configure drift by setting the following CLI argument: `--feature-gates Drift=true`.

| Feature | Default | Stage | Since | Until |
|---------|---------|-------|---------|---------|
| Drift | false | Alpha | v0.21.x | v0.32.x |
| Drift | true | Beta | v0.33.x | |

### Batching Parameters

The batching parameters control how Karpenter batches an incoming stream of pending pods. Reducing these values may trade off a slightly faster time from pending pod to node launch, in exchange for launching smaller nodes. Increasing the values can do the inverse. Karpenter provides reasonable defaults for these values, but if you have specific knowledge about your workloads you can tweak these parameters to match the expected rate of incoming pods.

For a standard deployment scale-up, the pods arrive at the QPS setting of the `kube-controller-manager`, and the default values are typically fine. These settings are intended for use cases where other systems may create large numbers of pods over a period of many seconds or minutes and there is a desire to batch them together.

#### `batchIdleDuration`

The `batchIdleDuration` is the period of time that a new pending pod extends the current batching window. This can be increased to handle scenarios where pods arrive slower than one second part, but it would be preferable if they were batched together onto a single larger node.

This value is expressed as a string value like `10s`, `1m` or `2h45m`. The valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`.

#### `batchMaxDuration`
#### Batch Idle Duration

The `batchMaxDuration` is the maximum period of time a batching window can be extended to. Increasing this value will allow the maximum batch window size to increase to collect more pending pods into a single batch at the expense of a longer delay from when the first pending pod was created.
The batch idle duration duration is the period of time that a new pending pod extends the current batching window. This can be increased to handle scenarios where pods arrive slower than one second part, but it would be preferable if they were batched together onto a single larger node.

This value is expressed as a string value like `10s`, `1m` or `2h45m`. The valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`.

### AWS Parameters

#### `aws.tags`

Global tags are applied to __all__ AWS infrastructure resources deployed by Karpenter. These resources include:

- Launch Templates
- Volumes
- Instances

Tags are specified by including a JSON object of string to string from tag key to tag value.
#### Batch Max Duration

```yaml
aws.tags: '{"custom-tag1-key": "custom-tag-value", "custom-tag2-key": "custom-tag-value"}'
```
The batch max duration is the maximum period of time a batching window can be extended to. Increasing this value will allow the maximum batch window size to increase to collect more pending pods into a single batch at the expense of a longer delay from when the first pending pod was created.

{{% alert title="Note" color="primary" %}}
Since you can specify tags at the global level and in the `AWSNodeTemplate` resource, if a key is specified in both locations, the `AWSNodeTemplate` tag value will override the global tag.
{{% /alert %}}
This value is expressed as a string value like `10s`, `1m` or `2h45m`. The valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`.

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