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Home Lab 4

With a Kubernetes cluster up and running, it’s time to bootstrap GitOps so I can automate configuration and deployment of applications.

What we’ll need:
- Istio for a Network Control Interface
- MetalLB for a bare-metal load balancer
- Certmanager to provide certificates for DNS
- Rook Ceph As a Container Storage Interface
- Gitea to provide git, the core to GitOps
- Flux to implement Gitops

Of course, I deployed all of this with Terraform!

Istio

Installing Istio is a bit of an undocumented pain with Terraform, so I had to use the kubectl_manifest resource:

resource "null_resource" "deploy_istio_operator" {
    provisioner "local-exec" {
        command = <<EOT
          # Download the chart because they refuse to actually support this
          git clone https://github.com/istio/istio || true
          helm install istio-operator istio/manifests/charts/istio-operator \
          --kubeconfig "${path.module}/../kubernetes/.kube/config" \
          --set operatorNamespace="istio-operator" \
          --set watchedNamespaces="istio-system"
        EOT
        interpreter = ["bash", "-c"]
    }
    provisioner "local-exec" {
      when = destroy
      command = <<EOT
        helm uninstall istio-operator --kubeconfig "${path.module}/../kubernetes/.kube/config"
      EOT
    }
}

resource "kubectl_manifest" "istio_profile" {
  yaml_body = <<EOT
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
metadata:
  name: istio-control-plane
  namespace: istio-system
spec:
  profile: default
  components:
    base:
      enabled: true
    pilot:
      enabled: true
    cni:
      enabled: true
    istiodRemote:
      enabled: false
    ingressGateways:
      - name: istio-ingressgateway
        enabled: true
    egressGateways:
      - name: istio-egressgateway
        enabled: true
  values:
    cni:
      excludeNamespaces:
       - istio-system
       - kube-system
       - metallb-system
      logLevel: info
  EOT
  depends_on = [
    null_resource.deploy_istio_operator
  ]
}

MetalLB

Similar to Istio, MetalLB has to be installed by generating manifests in-line:

// https://metallb.universe.tf/installation/
resource "null_resource" "install_metal_lb" {
    provisioner "local-exec" {
        command = <<EOT
          # see what changes would be made, returns nonzero returncode if different
          kubectl --kubeconfig ${path.module}/../kubernetes/.kube/config get configmap kube-proxy -n kube-system -o yaml | \
          sed -e "s/strictARP: false/strictARP: true/" | \
          kubectl diff -f - -n kube-system

          # actually apply the changes, returns nonzero returncode on errors only
          kubectl --kubeconfig ${path.module}/../kubernetes/.kube/config get configmap kube-proxy -n kube-system -o yaml | \
          sed -e "s/strictARP: false/strictARP: true/" | \
          kubectl apply -f - -n kube-system

          # Apply
          kubectl --kubeconfig "${path.module}/../kubernetes/.kube/config" apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.6/manifests/namespace.yaml
          kubectl --kubeconfig "${path.module}/../kubernetes/.kube/config" apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.6/manifests/metallb.yaml
          kubectl --kubeconfig "${path.module}/../kubernetes/.kube/config" create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"
        EOT
        interpreter = ["bash", "-c"]
    }
    provisioner "local-exec" {
        when = destroy
        command = <<EOT
           kubectl --kubeconfig ${path.module}/../kubernetes/.kube/config delete namespace metallb-system
        EOT
        interpreter = ["bash", "-c"]
    }
}


resource "local_file" "metallb-config" {
  content = <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: default
      protocol: layer2
      addresses:
      - ${var.LOAD_BALANCER_IP}/32
      avoid-buggy-ips: true
EOF
  filename = "${path.module}/config.yaml"
}

resource "null_resource" "config_metal_lb" {
    provisioner "local-exec" {
        command = <<EOT
           kubectl --kubeconfig "${path.module}/../kubernetes/.kube/config" apply -f ${path.module}/config.yaml
        EOT
        interpreter = ["bash", "-c"]
    }
    depends_on = [
      null_resource.install_metal_lb
    ]
    triggers = {
      "profile_manifest" = local_file.metallb-config.content
    }
}

Certmanager

Here we have something we can install with Helm:

// Create namespace to deploy into
resource "kubernetes_namespace" "cert-manager" {
  metadata {
    name = "cert-manager"
  }

  lifecycle {
    ignore_changes = [
      metadata[0].labels,
    ]
  }
}


resource "helm_release" "cert-manager" {
  name       = "cert-manager"
  repository = "https://charts.jetstack.io"
  chart      =   "cert-manager"
  namespace = "${kubernetes_namespace.cert-manager.metadata[0].name}"
  set {
    name = "installCRDs"
    value = true
  }
}

Rook-Ceph

Deploying ceph is a multi-part process, and due to their current lack of support for proper helm chart hosting you’ve got to clone the repo…

resource "null_resource" "download_rook_repo" {
    provisioner "local-exec" {
        command = "git clone https://github.com/rook/rook || true"
    }
}

Then you can create a namespace and deploy the chart, using template values of course

// Create namespace to deploy into
resource "kubernetes_namespace" "ceph" {
  metadata {
    annotations = {
      name = "rook-ceph"
    }

    labels = {
      namespace = "rook-ceph"
      istio-injection = "false"
    }

    name = "rook-ceph"
  }
}


data "template_file" "chart-values" {
    template = "${file("${path.module}/values.yaml.tpl")}"
    vars = {
    }
}


resource "helm_release" "rook-operator" {
  name       = "rook-ceph-operator"
  repository = "https://charts.rook.io/release"
  chart      =   "rook-ceph"
  namespace = "${kubernetes_namespace.ceph.metadata[0].name}"
  values = [
    "${data.template_file.chart-values.rendered}"
  ]
}



resource "helm_release" "rook-cluster" {
  name       = "rook-ceph-cluster"
  chart      =   "./rook/cluster/charts/rook-ceph-cluster"
  namespace = "${kubernetes_namespace.ceph.metadata[0].name}"
  values = [
    "${data.template_file.chart-values.rendered}"
  ]
  depends_on = [
    helm_release.rook-operator,
    null_resource.download_rook_repo
  ]
}

Then you can define the storage classes the cluster will use to back containers:

resource "kubectl_manifest" "block-pool" {
   yaml_body = <<EOT
apiVersion: ceph.rook.io/v1
kind: CephBlockPool
metadata:
  name: replicapool
  namespace: rook-ceph
spec:
  failureDomain: host
  replicated:
    size: 3
    # Disallow setting pool with replica 1, this could lead to data loss without recovery.
    # Make sure you're *ABSOLUTELY CERTAIN* that is what you want
    requireSafeReplicaSize: true
    # gives a hint (%) to Ceph in terms of expected consumption of the total cluster capacity of a given pool
    # for more info: https://docs.ceph.com/docs/master/rados/operations/placement-groups/#specifying-expected-pool-size
    #targetSizeRatio: .5
   EOT
   depends_on = [
     helm_release.rook-cluster
   ]
}

resource "kubectl_manifest" "storage-class" {
  yaml_body = <<EOT
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: rook-ceph-block
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
# Change "rook-ceph" provisioner prefix to match the operator namespace if needed
provisioner: rook-ceph.rbd.csi.ceph.com
parameters:
  # clusterID is the namespace where the rook cluster is running
  # If you change this namespace, also change the namespace below where the secret namespaces are defined
  clusterID: rook-ceph # namespace:cluster

  # If you want to use erasure coded pool with RBD, you need to create
  # two pools. one erasure coded and one replicated.
  # You need to specify the replicated pool here in the `pool` parameter, it is
  # used for the metadata of the images.
  # The erasure coded pool must be set as the `dataPool` parameter below.
  #dataPool: ec-data-pool
  pool: replicapool

  # (optional) mapOptions is a comma-separated list of map options.
  # For krbd options refer
  # https://docs.ceph.com/docs/master/man/8/rbd/#kernel-rbd-krbd-options
  # For nbd options refer
  # https://docs.ceph.com/docs/master/man/8/rbd-nbd/#options
  # mapOptions: lock_on_read,queue_depth=1024

  # (optional) unmapOptions is a comma-separated list of unmap options.
  # For krbd options refer
  # https://docs.ceph.com/docs/master/man/8/rbd/#kernel-rbd-krbd-options
  # For nbd options refer
  # https://docs.ceph.com/docs/master/man/8/rbd-nbd/#options
  # unmapOptions: force

  # RBD image format. Defaults to "2".
  imageFormat: "2"

  # RBD image features. Available for imageFormat: "2". CSI RBD currently supports only `layering` feature.
  imageFeatures: layering

  # The secrets contain Ceph admin credentials. These are generated automatically by the operator
  # in the same namespace as the cluster.
  csi.storage.k8s.io/provisioner-secret-name: rook-csi-rbd-provisioner
  csi.storage.k8s.io/provisioner-secret-namespace: rook-ceph # namespace:cluster
  csi.storage.k8s.io/controller-expand-secret-name: rook-csi-rbd-provisioner
  csi.storage.k8s.io/controller-expand-secret-namespace: rook-ceph # namespace:cluster
  csi.storage.k8s.io/node-stage-secret-name: rook-csi-rbd-node
  csi.storage.k8s.io/node-stage-secret-namespace: rook-ceph # namespace:cluster
  # Specify the filesystem type of the volume. If not specified, csi-provisioner
  # will set default as `ext4`. Note that `xfs` is not recommended due to potential deadlock
  # in hyperconverged settings where the volume is mounted on the same node as the osds.
  csi.storage.k8s.io/fstype: ext4
# uncomment the following to use rbd-nbd as mounter on supported nodes
# **IMPORTANT**: If you are using rbd-nbd as the mounter, during upgrade you will be hit a ceph-csi
# issue that causes the mount to be disconnected. You will need to follow special upgrade steps
# to restart your application pods. Therefore, this option is not recommended.
#mounter: rbd-nbd
allowVolumeExpansion: true
reclaimPolicy: Delete
  EOT
  depends_on = [
     kubectl_manifest.block-pool
   ]
}

resource "kubectl_manifest" "filesystem" {
   yaml_body = <<EOT
apiVersion: ceph.rook.io/v1
kind: CephFilesystem
metadata:
  name: cephfs
  namespace: rook-ceph
spec:
  metadataPool:
    replicated:
      size: 3
  dataPools:
    - replicated:
        size: 3
  preserveFilesystemOnDelete: true
  metadataServer:
    activeCount: 1
    activeStandby: true
   EOT
   depends_on = [
     helm_release.rook-cluster
   ]
}

resource "kubectl_manifest" "storage-class-fs" {
  yaml_body = <<EOT
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: rook-cephfs
provisioner: rook-ceph.cephfs.csi.ceph.com # driver:namespace:operator
parameters:
  # clusterID is the namespace where operator is deployed.
  clusterID: rook-ceph # namespace:cluster

  # CephFS filesystem name into which the volume shall be created
  fsName: cephfs

  # Ceph pool into which the volume shall be created
  # Required for provisionVolume: "true"
  pool: cephfs-data0

  # The secrets contain Ceph admin credentials. These are generated automatically by the operator
  # in the same namespace as the cluster.
  csi.storage.k8s.io/provisioner-secret-name: rook-csi-cephfs-provisioner
  csi.storage.k8s.io/provisioner-secret-namespace: rook-ceph # namespace:cluster
  csi.storage.k8s.io/controller-expand-secret-name: rook-csi-cephfs-provisioner
  csi.storage.k8s.io/controller-expand-secret-namespace: rook-ceph # namespace:cluster
  csi.storage.k8s.io/node-stage-secret-name: rook-csi-cephfs-node
  csi.storage.k8s.io/node-stage-secret-namespace: rook-ceph # namespace:cluster

  # (optional) The driver can use either ceph-fuse (fuse) or ceph kernel client (kernel)
  # If omitted, default volume mounter will be used - this is determined by probing for ceph-fuse
  # or by setting the default mounter explicitly via --volumemounter command-line argument.
  # mounter: kernel
reclaimPolicy: Delete
allowVolumeExpansion: true
mountOptions:
  # uncomment the following line for debugging
  #- debug
  EOT
  depends_on = [
     kubectl_manifest.filesystem
   ]
}

Gitea

Again, this is something we can install with Helm! This is actually a workload though and it’ll be our first. So we’re going to use the Gitea deployment to declare our storage classes and test our certificate/DNS/Load Balancing configuration.

Gitea doesn’t play nice with Istio, so there’s a little workaround I had to find to get there. This may be something I contribute to in the future.

Create certificates

// Generate a tls private key
resource "tls_private_key" "gitea-ca-key" {
  algorithm   = "ECDSA"
  ecdsa_curve = "P384"
}

// Generate a CA cert
resource "tls_self_signed_cert" "ca-cert" {
  key_algorithm   = "ECDSA"
  private_key_pem = tls_private_key.gitea-ca-key.private_key_pem

  subject {
    common_name  = "salmon.sec"
    organization = "Salmonsec"
  }
  // One year
  validity_period_hours = 8760

  allowed_uses = [
    "key_encipherment",
    "digital_signature",
    "server_auth",
    "cert_signing"
  ]
  is_ca_certificate = true
}

resource "local_file" "ca_cert" {
  content = tls_self_signed_cert.ca-cert.cert_pem
  filename = "Root_CA.pem"
}


# Generate a Kubernetes secret with the Git credentials
resource "kubernetes_secret" "ca-key-pair-gitea" {
  metadata {
    name      = "ca-key-pair-gitea"
    namespace = "istio-system"
  }

  data = {
    "tls.crt" = "${tls_self_signed_cert.ca-cert.cert_pem}"
    "tls.key" = "${tls_private_key.gitea-ca-key.private_key_pem}"
  }
}

resource "kubectl_manifest" "issuer" {
  yaml_body = <<EOT
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: selfsigned-issuer
  namespace: istio-system
spec:
  ca:
    secretName: ca-key-pair-gitea
  EOT
}

resource "kubectl_manifest" "certificate" {
  yaml_body = <<EOT
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: gitea-cert
  namespace: istio-system
spec:
  # Secret names are always required.
  secretName: self-signed-gitea-tls
  duration: 2160h # 90d
  renewBefore: 360h # 15d
  commonName: git.salmon.sec
  dnsNames:
  - git.salmon.sec
  issuerRef:
    name: selfsigned-issuer
  EOT
}

Define chart templated values:

#ingress:
#  enabled: true
#  hosts:
#    - git.salmon.sec
#  tls:
#    - secretName: self-signed-gitea-tls
#      hosts:
#        - git.salmon.sec
persistence:
  enabled: true
  size: 10Gi
  storageClass: rook-ceph-block
postgresql:
  persistence:
    size: 10Gi
    storageClass: rook-ceph-block
  volumePermissions:
    enabled: true
  service:
    annotations:
      networking.istio.io/exportTo: "."
gitea:
  admin:
    username: ${PACKER_SUDO_USER}
    password: ${PACKER_SUDO_PASS}
    email: "${PACKER_SUDO_USER}@${EMAIL_DOMAIN}"

Then deploy the chart:

// Create namespace to deploy into
resource "kubernetes_namespace" "gitea" {
  metadata {
    annotations = {
      name = "gitea"
    }

    labels = {
      namespace = "gitea"
      istio-injection = "enabled"
    }

    name = "gitea"
  }
}


data "template_file" "chart-values" {
    template = "${file("${path.module}/values.yaml.tpl")}"
    vars = {
        PACKER_SUDO_USER = "${var.PACKER_SUDO_USER}"
        PACKER_SUDO_PASS = "${var.PACKER_SUDO_PASS}"
        EMAIL_DOMAIN = "salmon.sec"
        HOST = "git.salmon.sec"
    }
}

resource "helm_release" "gitea" {
  name       = "gitea"
  repository = "https://dl.gitea.io/charts"
  chart      =   "gitea"
  version = "2.2.5"
  namespace = "${kubernetes_namespace.gitea.metadata[0].name}"
  values = [
    "${data.template_file.chart-values.rendered}"
  ]
  //depends_on = [
   // kubectl_manifest.gitea-pvc,
    //kubectl_manifest.gitea-pvc-postgres
  //]
}

resource "null_resource" "timeout" {
  provisioner "local-exec" {
    command = "sleep 30"
  }
}

resource "kubectl_manifest" "secret-patch" {
   yaml_body = <<EOT
apiVersion: v1
data:
  init_gitea.sh: 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
kind: Secret
metadata:
  name: gitea-init
  namespace: gitea
type: Opaque
   EOT
   depends_on = [
     null_resource.timeout
   ]
}

Notice the weird hack around init_gitea, see the issue referenced above to understand why that’s happening…
1

Flux

Flux actually has a terraform resource declaration, so installing it is amazingly easy!

// Create namespace to deploy into
resource "kubernetes_namespace" "flux_system" {
  metadata {
    name = "flux-system"
  }

  lifecycle {
    ignore_changes = [
      metadata[0].labels,
    ]
  }
}

# Generate manifests
data "flux_install" "main" {
  target_path    = "manifests/flux"
  network_policy = false
}

# Split multi-doc YAML with
# https://registry.terraform.io/providers/gavinbunney/kubectl/latest
data "kubectl_file_documents" "apply" {
  content = data.flux_install.main.content
}

# Convert documents list to include parsed yaml data
locals {
  apply = [ for v in data.kubectl_file_documents.apply.documents : {
      data: yamldecode(v)
      content: v
    }
  ]
}

# Apply manifests on the cluster
resource "kubectl_manifest" "apply" {
  for_each   = { for v in local.apply : lower(join("/", compact([v.data.apiVersion, v.data.kind, lookup(v.data.metadata, "namespace", ""), v.data.metadata.name]))) => v.content }
  depends_on = [kubernetes_namespace.flux_system]
  yaml_body = each.value
}

Add sync so it will pull manifests from a repo I’ll create next time ;)

# Generate manifests
data "flux_sync" "main" {
  target_path = "clusters/testing"
  url         = "https://git.salmon.sec/matt/birtast"
  branch = "master"
  name = "birtast"
}

# Split multi-doc YAML with
# https://registry.terraform.io/providers/gavinbunney/kubectl/latest
data "kubectl_file_documents" "sync" {
  content = data.flux_sync.main.content
}

# Convert documents list to include parsed yaml data
locals {
  sync = [ for v in data.kubectl_file_documents.sync.documents : {
      data: yamldecode(v)
      content: v
    }
  ]
}

# Apply manifests on the cluster
resource "kubectl_manifest" "sync" {
  for_each   = { for v in local.sync : lower(join("/", compact([v.data.apiVersion, v.data.kind, lookup(v.data.metadata, "namespace", ""), v.data.metadata.name]))) => v.content }
  depends_on = [kubernetes_namespace.flux_system]
  yaml_body = each.value
}

# Generate a Kubernetes secret with the Git credentials
resource "kubernetes_secret" "main" {
  depends_on = [kubectl_manifest.apply]

  metadata {
    name      = data.flux_sync.main.secret
    namespace = data.flux_sync.main.namespace
  }

  data = {
    username = var.PACKER_SUDO_USER
    password = var.PACKER_SUDO_PASS
    caFile = "${file("../gitea/Root_CA.pem")}"
  }
}

Awesome, now my cluster is all Bootstrapped for GitOps and will automatically pull manifests from ‘birtast’ of my Git cluster!

Directory
$ cd content && tree