Merge pull request #59655 from dims/targetted-check-for-etcd-port

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Check etcd port instead of process name

**What this PR does / why we need it**:

currently the pgrep check does not allow any etcd process to exist
other than the one we intend to start in our scripts. All we need
to know is if the port is free. So let us use netstat to check
if anyone is using that port. We don't really need to know if there
is another instance of etcd is running or not.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

hack/lib/etcd.sh

@@ -27,10 +27,10 @@ kube::etcd::validate() {
     exit 1
   }
 
-  # validate it is not running
-  if pgrep -x etcd >/dev/null 2>&1; then
-    kube::log::usage "etcd appears to already be running on this machine (`pgrep -xl etcd`) (or its a zombie and you need to kill its parent)."
-    kube::log::usage "retry after you resolve this etcd error."
+  # validate etcd port is free
+  if netstat -nat | grep "[\.:]${ETCD_PORT:?} .*LISTEN" >/dev/null 2>&1; then
+    kube::log::usage "unable to start etcd as port ${ETCD_PORT} is in use. please stop the process listening on this port and retry."
+    kube::log::usage "`netstat -nat | grep "[\.:]${ETCD_PORT:?} .*LISTEN"`"
     exit 1
   fi