Document steps for migrating from Ark to Velero

Signed-off-by: Nolan Brubaker <brubakern@vmware.com>

docs/migrating-to-velero.md

@@ -0,0 +1,82 @@
+# Migrating from Heptio Ark to Velero
+
+As of v0.11.0, Heptio Ark has become Velero. This means the following changes have been made:
+
+* The `ark` CLI client is now `velero`.
+* The default Kubernetes namespace and ServiceAccount are now named `velero` (formerly `heptio-ark`).
+* The container image name is now `gcr.io/heptio-images/velero` (formerly `gcr.io/heptio-images/ark`).
+* CRDs are now under the new `velero.io` API group name (formerly `ark.heptio.com`).
+
+
+The following instructions will help you migrate your existing Ark installation to Velero.
+
+# Prerequisites
+
+*  Ark v0.10.x installed. See the v0.10.x [upgrade instructions][1] to upgrade from older versions.
+* `kubectl` installed.
+* `cluster-admin` permissions.
+
+# Migration process
+
+At a high level, the migration process involves the following steps:
+
+* Scale down the `ark` deployment, so it will not process schedules, backups, or restores during the migration period.
+* Create a new namespace (named `velero` by default).
+* Apply the new CRDs.
+* Migrate existing Ark CRD objects, labels, and annotations to the new Velero equivalents.
+* Recreate the existing cloud credentials secret(s) in the velero namespace.
+* Apply the updated Kubernetes deployment and daemonset (for restic support) to use the new container images and namespace.
+* Remove the existing Ark namespace (which includes the deployment), CRDs, and ClusterRoleBinding.
+
+These steps are provided in a script here:
+
+```bash
+kubectl scale --namespace heptio-ark deployment/ark --replicas 0
+ OS=$(uname | tr '[:upper:]' '[:lower:]') # Determine if the OS is Linux or macOS
+ ARCH="amd64"
+
+# Download the velero client/example tarball to and unpack
+curl https://github.com/heptio/velero/releases/download/v0.11.0/velero-v0.11.0-${OS}-${ARCH}.tar.gz --output velero-v0.11.0-${OS}-${ARCH}.tar.gz
+tar xvf velero-v0.11.0-${OS}-${ARCH}.tar.gz
+
+# Create the prerequisite CRDs and namespace
+kubectl apply -f config/common/00-prereqs.yaml
+
+# Download and unpack the crd-migrator tool
+curl https://github.com/vmware/crd-migration-tool/releases/download/v1.0.0/crd-migration-tool-v1.0.0-${OS}-${ARCH}.tar.gz --output crd-migration-tool-v1.0.0-${OS}-${ARCH}.tar.gz
+tar xvf crd-migration-tool-v1.0.0-${OS}-${ARCH}.tar.gz
+
+# Run the tool against your cluster.
+./crd-migrator \
+    --from ark.heptio.com/v1 \
+    --to velero.io/v1 \
+    --label-mappings ark.heptio.com:velero.io,ark-schedule:velero.io/schedule-name \
+    --annotation-mappings ark.heptio.com:velero.io \
+    --namespace-mappings heptio-ark:velero
+
+
+# Copy the necessary secret from the ark namespace
+kubectl get secret --namespace heptio-ark cloud-credentials --export -o yaml | kubectl apply --namespace velero -f -
+
+# Apply the Velero deployment and restic DaemonSet for your platform
+## GCP
+#kubectl apply -f config/gcp/10-deployment.yaml
+#kubectl apply -f config/gcp/20-restic-daemonset.yaml
+## AWS
+#kubectl apply -f config/aws/10-deployment.yaml
+#kubectl apply -f config/aws/20-restic-daemonset.yaml
+## Azure
+#kubectl apply -f config/azure/00-deployment.yaml
+#kubectl apply -f config/azure/20-restic-daemonset.yaml
+
+# Verify your data is still present
+./velero get backup
+./velero get restore
+
+# Remove old Ark data
+kubectl delete namespace heptio-ark
+kubectl delete crds -l component=ark 
+kubectl delete clusterrolebindings -l component=ark
+```
+
+[1]: https://heptio.github.io/velero/v0.10.0/upgrading-to-v0.10