From e57b86795734c9188d1d42cd906a29a9e926024b Mon Sep 17 00:00:00 2001
From: Sandeep Rajan <srajan@infoblox.com>
Date: Fri, 24 May 2019 10:34:13 -0400
Subject: [PATCH] add coredns migration support to upgrade.sh

---
 cluster/gce/upgrade.sh | 83 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/cluster/gce/upgrade.sh b/cluster/gce/upgrade.sh
index b3460808165..60a7b9d4ae3 100755
--- a/cluster/gce/upgrade.sh
+++ b/cluster/gce/upgrade.sh
@@ -439,6 +439,85 @@ function do-node-upgrade() {
   echo "== Finished upgrading nodes to ${KUBE_VERSION}. ==" >&2
 }
 
+
+function update-coredns-config() {
+  # Get the current CoreDNS version
+  local -r coredns_addon_path="/etc/kubernetes/addons/0-dns/coredns"
+  local -r tmpdir=/tmp
+  local -r download_dir=$(mktemp --tmpdir=${tmpdir} -d coredns-migration.XXXXXXXXXX) || exit 1
+
+  # Get the new installed CoreDNS version
+  echo "Waiting for CoreDNS to update"
+  until [[ $(${KUBE_ROOT}/cluster/kubectl.sh -n kube-system get deployment coredns -o=jsonpath='{$.metadata.resourceVersion}') -ne ${COREDNS_DEPLOY_RESOURCE_VERSION} ]]; do
+     sleep 1
+  done
+  echo "Fetching the latest installed CoreDNS version"
+  NEW_COREDNS_VERSION=$(${KUBE_ROOT}/cluster/kubectl.sh -n kube-system get deployment coredns -o=jsonpath='{$.spec.template.spec.containers[:1].image}' | cut -d ":" -f 2)
+
+  case "$(uname -m)" in
+      x86_64*)
+        host_arch=amd64
+        ;;
+      i?86_64*)
+        host_arch=amd64
+        ;;
+      amd64*)
+        host_arch=amd64
+        ;;
+      aarch64*)
+        host_arch=arm64
+        ;;
+      arm64*)
+        host_arch=arm64
+        ;;
+      arm*)
+        host_arch=arm
+        ;;
+      i?86*)
+        host_arch=x86
+        ;;
+      s390x*)
+        host_arch=s390x
+        ;;
+      ppc64le*)
+        host_arch=ppc64le
+        ;;
+      *)
+        echo "Unsupported host arch. Must be x86_64, 386, arm, arm64, s390x or ppc64le." >&2
+        exit 1
+        ;;
+    esac
+
+  # Download the CoreDNS migration tool
+  echo "== Downloading the CoreDNS migration tool =="
+  wget -P ${download_dir} "https://github.com/coredns/corefile-migration/releases/download/v1.0.2/corefile-tool-${host_arch}" >/dev/null 2>&1
+  chmod +x ${download_dir}/corefile-tool-${host_arch}
+
+  # Migrate the CoreDNS ConfigMap depending on whether it is being downgraded or upgraded.
+  ${KUBE_ROOT}/cluster/kubectl.sh -n kube-system get cm coredns -o jsonpath='{.data.Corefile}' > ${download_dir}/Corefile-old
+
+  if test "$(printf '%s\n' ${CURRENT_COREDNS_VERSION} ${NEW_COREDNS_VERSION} | sort -V | head -n 1)" != ${NEW_COREDNS_VERSION}; then
+     echo "== Upgrading the CoreDNS ConfigMap =="
+     ./corefile-tool-${host_arch} migrate --from ${CURRENT_COREDNS_VERSION} --to ${NEW_COREDNS_VERSION} --corefile ${download_dir}/Corefile-old > ${download_dir}/Corefile
+     ${KUBE_ROOT}/cluster/kubectl.sh -n kube-system create configmap coredns --from-file ${download_dir}/Corefile -o yaml --dry-run | ${KUBE_ROOT}/cluster/kubectl.sh apply -f -
+  else
+     # In case of a downgrade, a custom CoreDNS Corefile will be overwritten by a default Corefile. In that case,
+     # the user will need to manually modify the resulting (default) Corefile after the downgrade is complete.
+     echo "== Applying the latest default CoreDNS configuration =="
+     gcloud compute --project ${PROJECT}  scp --zone ${ZONE} ${MASTER_NAME}:${coredns_addon_path}/coredns.yaml ${download_dir}/coredns-manifest.yaml > /dev/null
+     ${KUBE_ROOT}/cluster/kubectl.sh apply -f ${download_dir}/coredns-manifest.yaml
+  fi
+
+  # clean up
+  rm -rf ${download_dir}
+
+  echo "== The CoreDNS Config has been updated =="
+}
+
+echo "Fetching the previously installed CoreDNS version"
+CURRENT_COREDNS_VERSION=$(${KUBE_ROOT}/cluster/kubectl.sh -n kube-system get deployment coredns -o=jsonpath='{$.spec.template.spec.containers[:1].image}' | cut -d ":" -f 2)
+COREDNS_DEPLOY_RESOURCE_VERSION=$(${KUBE_ROOT}/cluster/kubectl.sh -n kube-system get deployment coredns -o=jsonpath='{$.metadata.resourceVersion}')
+
 master_upgrade=true
 node_upgrade=true
 node_prereqs=false
@@ -580,6 +659,10 @@ if [[ "${node_upgrade}" == "true" ]]; then
   fi
 fi
 
+if [[ "${CLUSTER_DNS_CORE_DNS:-}" == "true" ]]; then
+  update-coredns-config
+fi
+
 echo "== Validating cluster post-upgrade =="
 "${KUBE_ROOT}/cluster/validate-cluster.sh"