Thoughts on using Vault as the sole source for Kubernetes secrets?

Hey folks! 👋 As someone who lives and breathes API-driven automation, I've been diving deep into secret management for our Kubernetes clusters. The promise of a single, centralized, and dynamic source of truth for secrets is incredibly appealing—especially when you're trying to orchestrate dozens of microservices and automated workflows.

So, I've been prototyping using **HashiCorp Vault as the *sole* secret source for our K8s workloads**, bypassing native K8s Secrets entirely. The idea is to use the Vault Agent Injector or the Vault CSI Provider to mount secrets directly into pods. This approach seems to offer some major advantages:

* **Dynamic Secrets:** Generate short-lived database credentials or cloud IAM roles on-demand. This is a game-changer for security.
* **Fine-Grained Access Control:** Vault policies are incredibly detailed compared to basic K8s RBAC tied to Secrets.
* **Centralized Auditing & Management:** One log trail for all secret access, everywhere. No more wondering if a secret is also stored in a ConfigMap or hardcoded somewhere.
* **Secret Rotation:** APIs to easily rotate and manage secret lifecycles, which is pretty clunky with native Secrets.

Here's a snippet of the kind of Vault policy I'm talking about for a specific service:

```hcl
path "kv/data/prod/payment-service/*" {
capabilities = ["read"]
}

path "database/creds/payment-role" {
capabilities = ["read"]
}
```

And a fragment of the pod spec annotation for the injector:

```yaml
annotations:
vault.hashicorp.com/agent-inject: "true"
vault.hashicorp.com/role: "payment-service"
vault.hashicorp.com/agent-inject-secret-db-creds: "database/creds/payment-role"
```

However, I'm hitting some real-world complexities and I'd love the community's practical experiences.

* **Bootstrapping Chicken/Egg:** Vault itself needs credentials to run in K8s. How are you handling the initial trust? Using K8s Service Account JWT auth method? Something else?
* **Operational Overhead:** Now you have two critical systems (K8s *and* Vault) to keep highly available. Did this significantly increase your operational burden?
* **Developer Experience:** Did your dev teams struggle with the added layer of abstraction when debugging or developing locally?
* **Disaster Recovery:** If Vault has an outage, do your pods just... stop working? How do you architect for resilience without falling back to static secrets?

I'm all-in on the *theory* of this pattern—it feels like the right, secure, automatable future. But before I advocate for a full rollout, I need to understand the pitfalls and practical trade-offs from those who've walked this path.

What has your journey been like? Was it worth the complexity? Any major "gotchas" you wish you'd known about on day one?