chore: adding uds core prerequisites documentation

docs/deployment/prerequisites.md

@@ -0,0 +1,75 @@
+---
+title: UDS Prerequisites
+type: docs
+weight: 4
+---
+
+## UDS installation prerequisites
+
+`UDS Core` could run in any [Kuberentes](https://kubernetes.io/) setup, but sometimes customizations are needed based on environemnts. This is an attempt to document and link to relevant information to aid in setting up your [Kuberentes](https://kubernetes.io/) environment to ensure a successful `UDS Core` installation.  
+
+### RHEL
+---
+#### *ISTIO related changes*
+Solution is to create file `/etc/modules-load.d/istio-iptables.conf` with this content:
+
+```bash
+# These modules need to be loaded on boot so that Istio (as required by
+# UDS Core) runs properly.
+#
+# See also: https://github.com/istio/istio/issues/23009
+
+br_netfilter
+nf_nat
+xt_REDIRECT
+xt_owner
+iptable_nat
+iptable_mangle
+iptable_filter
+```
+
+```bash
+sudo systemctl stop firewalld
+sudo systemctl disable firewalld
+```
+
+### RKE2
+--- 
+* [Installation requirements](https://docs.rke2.io/install/requirements)
+* [Firewalld network conflicts](https://docs.rke2.io/known_issues#firewalld-conflicts-with-default-networking)
+* [Disabling components, such as Ingress which clashes with istio](https://docs.rke2.io/advanced#disabling-server-charts)
+* [Defense Unicorns os prep script for rke2](https://github.com/defenseunicorns/uds-rke2-image-builder/blob/main/packer/scripts/os-prep.sh)
+
+
+### K3S
+---
+* [OS requirements](https://docs.k3s.io/installation/requirements#operating-systems)
+
+
+
+### UDS Core components
+---
+#### UDS Operator
+#### Istio 
+* [Platform requirements](https://istio.io/latest/docs/ops/deployment/platform-requirements/)
+#### Keycloak
+* [Configuration guide](https://www.keycloak.org/keycloak-benchmark/kubernetes-guide/latest/)
+#### Neuvector
+#### Loki
+#### Prometheus
+#### Promtail
+#### Grafana
+#### Authservice
+#### Velero
+#### Metrics Server
+* Optional component and can be added if needed. Most of the provided managed clsuters will provide you a metric server.
+```yaml
+...
+- name: uds-core
+  repository: ghcr.io/defenseunicorns/packages/private/uds/core
+  ref: 0.25.2-unicorn
+  optionalComponents:
+    - metrics-server
+...
+```
+