pin k8s versions with integration tests (#7236)

Fixes #7112

This pins the default integration tests to run on the latest
k3d version by retrieving the latest k3d binary, while also
pinning `helm-deep` to run on `v1.20+` (our min k8s version). T
his way we have integration tests running on both sides
(i.e latest and minimum)

Changes include:

- Update `./bin/k3d` to always retrieve the latest k3d binary and
  use it.
- Update `_test-helpers.sh` to use min version image for `helm-deep`.
  here, we also replace flags that are removed and replaced
  with newer ones with the latest k3d binary.

I've tried to find a GitHub action for K3s, but most of them seem to
be have a had a release while ago, and not goes well with our plan of
somehow getting the latest k8s.

Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>
(cherry picked from commit 5ba7d04)
Signed-off-by: Oliver Gould <ver@buoyant.io>

Author: Pothulapati

bin/_test-helpers.sh

@@ -215,6 +215,7 @@ check_linkerd_binary() {
 
 check_cluster() {
   check_if_k8s_reachable
+  kubectl version
   check_if_l5d_exists
 }
 
@@ -229,6 +230,18 @@ cleanup_cluster() {
   exit_on_err 'error removing existing Linkerd resources'
 }
 
+setup_min_cluster() {
+  local name=$1
+  export helm_path="$bindir"/helm
+
+  test_setup
+  if [ -z "$skip_cluster_create" ]; then
+    "$bindir"/k3d cluster create "$@"  --image +v1.20
+    image_load "$name"
+  fi
+  check_cluster
+}
+
 setup_cluster() {
   local name=$1
   export helm_path="$bindir"/helm
@@ -304,20 +317,20 @@ image_load() {
 
 start_test() {
   local name=$1
-  local config=(--no-hostip --k3s-server-arg '--disable=local-storage,metrics-server')
+  local config=(--k3s-arg '--disable=local-storage,metrics-server@server:0')
 
   case $name in
     cluster-domain)
-      config=("$name" "${config[@]}" --no-lb --k3s-server-arg --cluster-domain=custom.domain --k3s-server-arg '--disable=servicelb,traefik')
+      config=("$name" "${config[@]}" --no-lb --k3s-arg --cluster-domain=custom.domain --k3s-arg '--disable=servicelb,traefik@server:0')
       ;;
     cni-calico-deep)
-      config=("$name" "${config[@]}" --no-lb --k3s-server-arg --write-kubeconfig-mode=644 --k3s-server-arg --flannel-backend=none --k3s-server-arg --cluster-cidr=192.168.0.0/16 --k3s-server-arg '--disable=servicelb,traefik')
+      config=("$name" "${config[@]}" --no-lb --k3s-arg --write-kubeconfig-mode=644 --k3s-arg --flannel-backend=none --k3s-arg --cluster-cidr=192.168.0.0/16 --k3s-arg '--disable=servicelb,traefik@server:0')
       ;;
     multicluster)
       config=("${config[@]}" --network multicluster-test)
       ;;
     *)
-      config=("$name" "${config[@]}" --no-lb --k3s-server-arg '--disable=servicelb,traefik')
+      config=("$name" "${config[@]}" --no-lb --k3s-arg '--disable=servicelb,traefik@server:0')
       ;;
   esac
 
@@ -330,7 +343,11 @@ start_test() {
 
 start_single_test() {
   name=$1
-  setup_cluster "$@"
+  if [ "$name" == "helm-deep" ]; then
+    setup_min_cluster "$@"
+  else
+    setup_cluster "$@"
+  fi
   if [ -n "$cleanup_docker" ]; then
     rm -rf image-archives
     docker system prune --force --all

bin/k3d

@@ -2,11 +2,9 @@
 
 set -eu
 
-k3dversion=v4.4.5
-
 bindir=$( cd "${0%/*}" && pwd )
 targetbin=$( cd "$bindir"/.. && pwd )/target/bin
-k3dbin=$targetbin/.k3d-$k3dversion
+k3dbin=$targetbin/.k3d
 
 if [ ! -f "$k3dbin" ]; then
   if [ "$(uname -s)" = Darwin ]; then
@@ -24,7 +22,7 @@ if [ ! -f "$k3dbin" ]; then
   fi
 
   mkdir -p "$targetbin"
-  curl -sfL -o "$k3dbin" https://github.com/rancher/k3d/releases/download/$k3dversion/k3d-$os-$arch
+  curl -sfL -o "$k3dbin" https://github.com/rancher/k3d/releases/latest/download/k3d-$os-$arch
   chmod +x "$k3dbin"
 fi