Create & update Installation folder _index.md

Remove the following sections to be included in the Bootstrap section later as per fluxcd#1560

Generic Git Server
GitHub
GitLab
BitBucket
AWS CodeCommit
Azure DevOps
Google Cloud Source

Signed-off-by: mehak151 <[email protected]>

content/en/flux/installation/_index.md

@@ -0,0 +1,308 @@
+---
+title: "Installation"
+description: "Flux install, bootstrap, upgrade and uninstall documentation."
+weight: 30
+---
+
+This guide walks you through setting up Flux to
+manage one or more Kubernetes clusters.
+
+## Prerequisites
+
+You will need a Kubernetes cluster that matches one of the following versions:
+
+| Kubernetes version | Minimum required |
+|--------------------|------------------|
+| `v1.24`            | `>= 1.24.0`      |
+| `v1.25`            | `>= 1.25.0`      |
+| `v1.26`            | `>= 1.26.0`      |
+| `v1.27` and later  | `>= 1.27.1`      |
+
+{{% alert color="info" title="Kubernetes EOL" %}}
+Note that Flux may work on older versions of Kubernetes e.g. 1.19,
+but we don't recommend running [EOL versions](https://endoflife.date/kubernetes)
+in production nor do we offer support for these versions.
+{{% /alert %}}
+
+## Install the Flux CLI
+
+The Flux CLI is available as a binary executable for all major platforms,
+the binaries can be downloaded from GitHub
+[releases page](https://github.com/fluxcd/flux2/releases).
+
+{{< tabpane text=true >}}
+{{% tab header="Homebrew" %}}
+
+With [Homebrew](https://brew.sh) for macOS and Linux:
+
+```sh
+brew install fluxcd/tap/flux
+```
+
+{{% /tab %}}
+{{% tab header="bash" %}}
+
+With [Bash](https://www.gnu.org/software/bash/) for macOS and Linux:
+
+```sh
+curl -s https://fluxcd.io/install.sh | sudo bash
+```
+
+{{% /tab %}}
+{{% tab header="yay" %}}
+
+With [yay](https://github.com/Jguer/yay) (or another [AUR helper](https://wiki.archlinux.org/title/AUR_helpers)) for Arch Linux:
+
+```sh
+yay -S flux-bin
+```
+
+{{% /tab %}}
+{{% tab header="nix" %}}
+
+With [nix-env](https://nixos.org/manual/nix/unstable/command-ref/nix-env.html) for NixOS:
+
+```sh
+nix-env -i fluxcd
+```
+
+{{% /tab %}}
+{{% tab header="Chocolatey" %}}
+
+With [Chocolatey](https://chocolatey.org/) for Windows:
+
+```powershell
+choco install flux
+```
+
+{{% /tab %}}
+{{< /tabpane >}}
+
+To configure your shell to load `flux` [bash completions](./cmd/flux_completion_bash.md) add to your profile:
+
+```sh
+. <(flux completion bash)
+```
+
+[`zsh`](./cmd/flux_completion_zsh.md), [`fish`](./cmd/flux_completion_fish.md),
+and [`powershell`](./cmd/flux_completion_powershell.md)
+are also supported with their own sub-commands.
+
+A container image with `kubectl` and `flux` is available on DockerHub and GitHub:
+
+* `docker.io/fluxcd/flux-cli:<version>`
+* `ghcr.io/fluxcd/flux-cli:<version>`
+
+## Bootstrap
+
+Using the `flux bootstrap` command you can install Flux on a
+Kubernetes cluster and configure it to manage itself from a Git
+repository.
+
+If the Flux components are present on the cluster, the bootstrap
+command will perform an upgrade if needed. The bootstrap is
+idempotent, it's safe to run the command as many times as you want.
+
+The Flux component images are published to DockerHub and GitHub Container Registry
+as [multi-arch container images](https://docs.docker.com/docker-for-mac/multi-arch/)
+with support for Linux `amd64`, `arm64` and `armv7` (e.g. 32bit Raspberry Pi)
+architectures.
+
+If your Git provider is **AWS CodeCommit**, **Azure DevOps**, **Bitbucket Server**, **GitHub** or **GitLab** please
+follow the specific bootstrap procedure:
+
+* [AWS CodeCommit](./bootstrap/aws-code-commit.md#flux-installation-for-aws-codecommit)
+* [Azure DevOps](./bootstrap/azure.md#flux-installation-for-azure-devops)
+* [Bitbucket Server and Data Center](./bootstrap/bitbucket.md#bitbucket-server-and-data-center)
+* [GitHub.com and GitHub Enterprise](./bootstrap/github.md#github-and-github-enterprise)
+* [GitLab.com and GitLab Enterprise](./bootstrap/gitlab.md#gitlab-and-gitlab-enterprise)
+
+## Bootstrap with Terraform
+
+The bootstrap procedure can be implemented with Terraform using the Flux provider published on
+[registry.terraform.io](https://registry.terraform.io/providers/fluxcd/flux).
+The provider offers a Terraform resource called
+[flux_bootstrap_git](https://registry.terraform.io/providers/fluxcd/flux/latest/docs/resources/bootstrap_git)
+that can be used to bootstrap Flux in the same way the Flux CLI does it.
+
+Example of Git HTTPS bootstrap:
+
+```hcl
+provider "flux" {
+  kubernetes = {
+    config_path = "~/.kube/config"
+  }
+  git = {
+    url  = var.gitlab_url
+    http = {
+      username = var.gitlab_user
+      password = var.gitlab_token
+    }
+  }
+}
+
+resource "flux_bootstrap_git" "this" {
+  path                   = "clusters/my-cluster"
+  network_policy         = true
+  kustomization_override = file("${path.module}/kustomization.yaml")
+}
+```
+
+For more details on how to use the Terraform provider
+please see the [Flux docs on registry.terraform.io](https://registry.terraform.io/providers/fluxcd/flux/latest/docs).
+
+## Customize Flux manifests
+
+You can customize the Flux components before or after running bootstrap.
+
+Assuming you want to customise the Flux controllers before they get deployed on the cluster,
+first you'll need to create a Git repository and clone it locally.
+
+Create the file structure required by bootstrap with:
+
+```sh
+mkdir -p clusters/my-cluster/flux-system
+touch clusters/my-cluster/flux-system/gotk-components.yaml \
+    clusters/my-cluster/flux-system/gotk-sync.yaml \
+    clusters/my-cluster/flux-system/kustomization.yaml
+```
+
+Add patches to `kustomization.yaml`:
+
+```yaml
+apiVersion: kustomize.config.k8s.io/v1
+kind: Kustomization
+resources: # manifests generated during bootstrap
+  - gotk-components.yaml
+  - gotk-sync.yaml
+
+patches: # customize the manifests during bootstrap
+  - target:
+      kind: Deployment
+      labelSelector: app.kubernetes.io/part-of=flux
+    patch: |
+      # strategic merge or JSON patch
+```
+
+Push the changes to main branch:
+
+```sh
+git add -A && git commit -m "init flux" && git push
+```
+
+And run the bootstrap for `clusters/my-cluster`:
+
+```sh
+flux bootstrap git \
+  --url=ssh://git@<host>/<org>/<repository> \
+  --branch=main \
+  --path=clusters/my-cluster
+```
+
+To make further amendments, pull the changes locally,
+edit the `kustomization.yaml` file, push the changes upstream
+and rerun bootstrap or let Flux upgrade itself.
+
+Checkout the [bootstrap cheatsheet](../cheatsheets/bootstrap) for various examples of how to customize Flux.
+
+### Multi-tenancy lockdown
+
+Assuming you want to lock down Flux on multi-tenant clusters,
+add the following patches to `clusters/my-cluster/flux-system/kustomization.yaml`:
+
+```yaml
+apiVersion: kustomize.config.k8s.io/v1
+kind: Kustomization
+resources:
+  - gotk-components.yaml
+  - gotk-sync.yaml
+patches:
+  - patch: |
+      - op: add
+        path: /spec/template/spec/containers/0/args/0
+        value: --no-cross-namespace-refs=true
+    target:
+      kind: Deployment
+      name: "(kustomize-controller|helm-controller|notification-controller|image-reflector-controller|image-automation-controller)"
+  - patch: |
+      - op: add
+        path: /spec/template/spec/containers/0/args/-
+        value: --no-remote-bases=true
+    target:
+      kind: Deployment
+      name: "kustomize-controller"
+  - patch: |
+      - op: add
+        path: /spec/template/spec/containers/0/args/0
+        value: --default-service-account=default
+    target:
+      kind: Deployment
+      name: "(kustomize-controller|helm-controller)"
+  - patch: |
+      - op: add
+        path: /spec/serviceAccountName
+        value: kustomize-controller
+    target:
+      kind: Kustomization
+      name: "flux-system"
+```
+
+With the above configuration, Flux will:
+
+- Deny cross-namespace access to Flux custom resources, thus ensuring that a tenant can't use another tenant's sources or subscribe to their events.
+- Deny accesses to Kustomize remote bases, thus ensuring all resources refer to local files, meaning only the Flux Sources can affect the cluster-state.
+- All `Kustomizations` and `HelmReleases` which don't have `spec.serviceAccountName` specified, will use the `default` account from the tenant's namespace.
+  Tenants have to specify a service account in their Flux resources to be able to deploy workloads in their namespaces as the `default` account has no permissions.
+- The flux-system `Kustomization` is set to reconcile under a service account with cluster-admin role,
+  allowing platform admins to configure cluster-wide resources and provision the tenant's namespaces, service accounts and RBAC.
+
+To apply these patches, push the changes to the main branch and run `flux bootstrap`.
+
+## Dev install
+
+For testing purposes you can install Flux without storing its manifests in a Git repository:
+
+```sh
+flux install
+```
+
+Or using kubectl:
+
+```sh
+kubectl apply -f https://github.com/fluxcd/flux2/releases/latest/download/install.yaml
+```
+
+Then you can register Git repositories and reconcile them on your cluster:
+
+```sh
+flux create source git podinfo \
+  --url=https://github.com/stefanprodan/podinfo \
+  --tag-semver=">=4.0.0" \
+  --interval=1m
+
+flux create kustomization podinfo-default \
+  --source=podinfo \
+  --path="./kustomize" \
+  --prune=true \
+  --validation=client \
+  --interval=10m \
+  --health-check="Deployment/podinfo.default" \
+  --health-check-timeout=2m \
+  --target-namespace=default
+```
+
+You can register Helm repositories and create Helm releases:
+
+```sh
+flux create source helm bitnami \
+  --interval=1h \
+  --url=https://charts.bitnami.com/bitnami
+
+flux create helmrelease nginx \
+  --interval=1h \
+  --release-name=nginx-ingress-controller \
+  --target-namespace=kube-system \
+  --source=HelmRepository/bitnami \
+  --chart=nginx-ingress-controller \
+  --chart-version="5.x.x"
+```