docs: Clarify conceptual docs around Exists operator

[jonathan-innis]

Fixes #6058

Description

Clarify some details around the Exists operator that caused confusion inside of the conceptual docs.

How was this change tested?

make presubmit

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[netlify]

✅ Deploy Preview for karpenter-docs-prod ready!

Name	Link
🔨 Latest commit	3135a47
🔍 Latest deploy log	https://app.netlify.com/sites/karpenter-docs-prod/deploys/6625a5c7ceeef80008056bb6
😎 Deploy Preview	https://deploy-preview-6070--karpenter-docs-prod.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[coveralls]

Pull Request Test Coverage Report for Build 8776363486

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.02%) to 81.963%

---

Files with Coverage Reduction	New Missed Lines	%
pkg/providers/amifamily/ami.go	1	90.32%

Totals
Change from base Build 8769944868:	-0.02%
Covered Lines:	5394
Relevant Lines:	6581

---

💛 - Coveralls

[Nuru]

@jonathan-innis Thank you for this clarification.

I still find the statement "you can isolate pods onto different nodes based on their values" a bit ambiguous with regard to pods that do not have node selectors/affinities. In the example given, you are assured that Team A pods and Team B pods are assigned different nodes, but you are not assured that other pods are not also assigned to those nodes, so the Team pods are not as isolated as one may desire.

How about changing the alert:

If a workload matches the NodePool but doesn't specify a label, Karpenter will generate a random label for the node.

To something like:

Note that by themselves, the node labels do not exclude workloads. If a workload matches the NodePool but doesn't specify a node selector or affinity, it can be assigned to any node, including the team-a or team-b nodes in the above example. If there is not an existing labeled node with capacity for the pod, Karpenter will launch a new node with a randomly generated value for the required label key.

[jigisha620]

LGTM